BENGUELA CURRENT LARGE MARINE
ECOSYSTEM PROGRAMME
(BCLME)
A regional commitment to the sustainable integrated management
of the Benguela Current Large Marine Ecosystem
by Angola, Namibia and South Africa
TRANSBOUNDARY DIAGNOSTIC ANALYSIS
(TDA)
UNDP
WINDHOEK, OCTOBER 1999
TABLE OF CONTENTS
Page
Background and Introduction
*
The Benguela: a unique environment
1
*
Fragmented management: a legacy of the
2
colonial and political past
*
The need for international action
2
*
The success story of BENEFIT
3
*
The emerging BCLME Programme
5
*
What has been achieved
5
*
Towards a sustainable future: the next steps
7
Users Guide to the Transboundary Diagnostic Analysis
9
*
Definitions and TDA objective
9
*
Design of the TDA
9
(a) Level One: Synthesis
9
(b) Level Two: Specifics
10
*
More
information
10
BCLME Transboundary Diagnostic Analysis
11
*
Geographic scope and ecosystem boundaries
12
*
Level One: Synthesis
14
*
Level Two: Overview
15
*
Analysis Tables and Explanatory Notes
17
* Synthesis Matrix
A: Sustainable management and
Utilization
of
resources
B: Assessment of Environmental variability,
ecosystem impacts and improvement of
predictability
C: Maintenance of ecosystem health and
management
of
pollution
Supporting Documents
*
Report on First Regional BCLME Workshop
*
Report on Second Regional BCLME Workshop
*
Thematic Reports 1-6
BACKGROUND AND INTRODUCTION
The Benguela: A Unique Environment
The Benguela Current Large Marine Ecosystem (BCLME) is situated along the coast of south western
Africa, stretching from east of the Cape of Good Hope in the south equatorwards to the Angola Front
which is situated near the northern geopolitical boundary of Angola (see Fig.1). It encompasses one of
the four major coastal upwelling ecosystems of the world which lie at the eastern boundaries of the
oceans. Like the Humboldt, California and Canary systems, the Benguela is an important centre of
marine biodiversity and marine food production. The BCLME's distinctive bathymetry, hydrography,
chemistry and trophodynamics combine to make it one of the most productive ocean areas in the
world, with a mean annual primary productivity of 1.25grams of carbon per square metre per year -
about six times higher than the North Sea ecosystem. This high level of primary productivity of the
BCLME supports an important global reservoir of biodiversity and biomass of zooplankton, fish, sea
birds and marine mammals, while near-shore and off-shore sediments hold rich deposits of precious
minerals (particularly diamonds), as well as oil and gas reserves. The natural beauty of the coastal
regions, many of which are still pristine by global standards, have also enabled the development of
significant tourism in some areas. Pollution from industries and poorly planned and managed coastal
developments and near-shore activities is, however, resulting in a rapid degradation of vulnerable
coastal habitats.
The Namib Desert which forms the landward boundary of a large part of the BCLME is one of the
oldest deserts in the world, predating the commencement of persistent upwelling in the Benguela (12
million years before present) by at least 40 million years. The upwelling system in the form in which
we know it today is about 2 million years old. The principal upwelling centre in the Benguela which is
situated near Lüderitz in southern Namibia, is the most concentrated and intense found in any
upwelling regime. What also makes the Benguela upwelling system so unique in the global context is
that it is bounded at both northern and southern ends by warm water systems, viz. the
tropical/equatorial Eastern Atlantic and the Indian Ocean's Agulhas Current respectively. Sharp
horizontal gradients (fronts) exist at these boundaries of the upwelling system, but these display
substantial variability in time and in space - at times pulsating in phase and at others not. Interaction
between the BCLME and the adjacent ocean systems occurs over thousands of kilometers. For
example, much of the BCLME, in particular off Namibia and Angola, is naturally hypoxic - even
anoxic - at depth as a consequence of subsurface flow southwards from the tropical Atlantic. This is
compounded by depletion of oxygen from more localised biological decay processes. There are also
teleconnections between the Benguela and processes in the North Atlantic and Indo-Pacific Oceans
(e.g. El Niño). Moreover, the southern Benguela lies at a major choke point in the "Global Climate
Conveyor Belt" whereby on time scales of decades to centuries warm surface waters move from the
Pacific via the Indian Ocean through into the North Atlantic. (The South Atlantic is the only ocean in
which there is a net transport of heat towards the equator!). As a consequence not only is the
Benguela at a critical location in terms of the global climate system, but it is also potentially extremely
vulnerable to any future climate change or increasing variability in climate.
Centuries before the arrival in southern Africa of the first European explorers and settlers, indigenous
coastal peoples harvested intertidal and near-shore marine life. Commercial exploitation in the
BCLME commenced in the first part of the seventeenth century with the harvesting of fur seals and
was followed by extensive whaling operations in the eighteenth and nineteenth centuries. Commercial
trawling started around 1900 and commercial purse-seine fishing for sardine some 50 years later.
Fisheries expanded rapidly in the 1960s and 1970s during a period when there was heavy exploitation
of resources by foreign fleets - resulting in the severe depletion and collapse of several fish stocks.
Superimposed on this fishing pressure was the impact of the inherent natural environmental ecosystem
variability and change. Together with the other factors mentioned in the following paragraphs, this has
made the sustainable use and management of BCLME living resources difficult.
1
Fragmented Management: A Legacy of the Colonial and Political Past
Following the establishment of European settlements at strategic coastal locations where victuals and
water could be procured to supply fleets trading with the East Indies, the potential wealth of the
African continent became apparent. This resulted in the great rush for territories and the colonisation
of the continent - mostly during the nineteenth century. Boundaries between colonies were hastily
established, often arbitrary and generally with little regard for indigenous inhabitants and natural
habitats. Colonial land boundaries in the Benguela region were established at rivers (Cunene, Orange).
Not only were the languages and cultures of the foreign occupiers different (Portuguese, German,
English, Dutch) but so were the management systems and laws which evolved in the three now
independent and democratic countries of the region - Angola, Namibia and South Africa. Moreover,
not only were the governance frameworks very different, but a further consequence of European
influence was the relative absence of inter-agency (or inter-ministerial) frameworks for management
of the marine environment and its resources and scant regard for sustainability. To this day mining
concessions, oil/gas exploration, fishing rights and coastal development have taken place with little or
no proper integration or regard for other users. For example, exploratory wells have been sunk in
established fishing grounds and the well-heads (which stand above of the sea bed) subsequently
abandoned. Likewise the impact of habitat alterations due to mining activities and ecosystem
alteration (including biodiversity impacts) due to fishing have not been properly assessed.
Prior to the coming into being of the United Nations Convention on the Law of the Sea and
declaration and respecting of sovereign rights within individual countries' Exclusive Economic (or
Fishing) Zones, there was an explosion of foreign fleets fishing off Angola, Namibia and South Africa
during the 1960s and 1970s - an effective imperialism and colonisation by mainly First World
countries of the BCLME, and the rape of its resources. This period also coincided with liberation
struggles in all three countries, and associated civil wars. In the case of Namibia, over whom the
mandate by South Africa was not internationally recognised, there was an added problem in that prior
to independence in 1990, an EEZ could not be proclaimed. In an attempt to control the foreign
exploitation of Namibia's fish resources, the International Commission for the South-east Atlantic
Fisheries (ICSEAF) was established, but this proved to be relatively ineffectual at husbanding the fish
stocks. In South Africa prior to 1994, environmental issues and sustainable management were low on
the political agenda. Moreover, the legacy of the past has resulted in a marked gradient in capacity
from south to north in the region. Consequences of the civil wars have been the human population
migration to the coast, localised pressure on marine and coastal resources (e.g. destruction of coastal
forests and mangroves), and severe pollution of some embayments.
While mineral exploration and extraction and developments in the coastal zones obviously occur
within the geographic boundaries of the three countries, i.e. within the EEZs, and can to a large degree
be independently managed by each of the countries, mobile living marine resources do not respect the
arbitrary geographic borders. This has obvious implications for the sustainable use of these resources,
particularly so in the case of straddling and shared fish stocks.
Thus the legacy of the colonial and political past is that the management of resources in the greater
Benguela area has not been integrated within countries or within the region. The real challenge of the
BCLME will be to develop a viable joint and integrative mechanism for the sustainable environmental
management of the region as a whole, i.e. at the ecosystem level.
The Need for International Action
In the BCLME the issue of sustainable ecosystem management under conditions of environmental
variability and uncertainty within a developing regional context presents an ideal opportunity for the
international community to provide material assistance to enable the three countries, via a joint
2
partnership, to establish and implement the appropriate framework for management actions. Countries
such as Norway and Germany are already providing much needed expertise and assistance through the
coordinated regional BENEFIT mechanism (discussed in the next section), but there is a clear need for
greater international involvement to enable the region, for example, to repair the damage done by the
ravages of gross over-exploitation of fish resources by foreign fleets in the 1960s, 1970s and 1980s.
As has been previously mentioned there exists a sharp capacity gradient (human and infrastructure)
from south to north in the BCLME, and while there is a very obvious willingness in the region to
share knowledge, expertise and facilities with those who are more disadvantaged, international
commitment from the GEF (Global Environmental Facility) International Waters Programme towards
capacity and institutional strengthening, and integrated management will greatly help accelerate this
process.
As has been noted, the mobile components of the BCLME do not respect the arbitrary geopolitical
(country) boundaries. Several fish stock straddle or are shared between the countries or otherwise
migrate through the Benguela. Actions by one country, e.g. over-exploitation or habitat destruction, of
their part of a migrating or shared resource could in effect negatively impact on one or both
neighbouring countries. Joint management and protection of shared stocks is one of the few available
options to the countries bordering the BCLME. In this manner, a better sense of ownership of the
regions' resources can be attained, and "owners" tend to protect their property more so than those
enjoying a free service. There is thus a strong need for harmonising legal and policy objectives and for
developing common strategies for resource surveys, and investment in sustainable ecosystem
management for the benefit of all the people in the Benguela region. Only concerted regional action
and enablement from the international community to develop regional agreements, and legal
frameworks and assessment/implementation strategies will in the longer term protect the biological
diversity of the greater Benguela.
While shared living resources present the most obvious case for co-management, there are many
activities and issues which can benefit from expertise and management structures developed and
implemented in individual countries. These include inter alia mining, declining coastal water quality
(pollution abatement and control, oil spill clean-up technology) oil/gas extraction, coastal zone
development, tourism and eco-tourism development, mitigation of the effects of introduced species
(aliens) and harmful algal blooms - which can also have system-wide impacts.
The BCLME Programme, which builds on existing regional capacity and goodwill, could serve as a
blueprint for the design and implementation of LME initiatives in other upwelling regions and
elsewhere in the developing world. Moreover, the BCLME Programme will address key regional
environmental variability issues that are expected to make a major contribution towards understanding
global fluctuations in the marine environment, including climate change.
The Success Story of BENEFIT
In April 1997 a major regional cooperative initiative was launched jointly by Angola, Namibia and
South Africa together with foreign partners "to develop the enhanced science capacity required for the
optimal and sustainable utilization of living resources of the Benguela ecosystem by (a) improving
knowledge and understanding of the dynamics of important commercial stocks, their environment and
linkages between the environmental processes and the stock dynamics, and (b) building appropriate
human and material capacity for marine science and technology in the countries bordering the
Benguela ecosystem". This BENEFIT (BENguela-Environment-Fisheries-Interaction & Training)
Programme evolved out of a Workshop/Seminar on "Fisheries Resource Dynamics in the Benguela
Current Ecosystem" held in Swakopmund in mid-1995 which was hosted by the Namibian Ministry of
Fisheries and Marine Resources in partnership with the Norwegian Agency for Development Co-
operation (NORAD), the German Organisation for Technical Co-operation (GTZ) and the
Intergovernmental Oceanographic Commission (IOC) of UNESCO. BENEFIT was developed in the
region by Angola, Namibia and South Africa and is jointly managed and directed by the three
3
countries. BENEFIT has attracted substantial incremental support from overseas countries and
international donor agencies. It remains, however, essentially a regional "self help" initiative, and has
been endorsed by the Southern African Development Community (SADC) and accepted as a SADC
programme. It is providing a unique opportunity for development of partnerships within and beyond
the southern African region in science and technology to promote optimum utilization of natural
resources and thereby greater food security in the region.
BENEFIT has been planned in two five-year phases (1997-2002, 2002-2007). The science and
technology component of BENEFIT has three foci, viz resource dynamics, the environment (of the
resources) and linkages between resources and the environment. These foci are increasing knowledge
of resource dynamics through improved research on the resources and their variable environment. The
capacity development component of the Programme is being addressed through a suite of task-
orientated framework activities to (a) build human capacity, particularly in areas of greatest need and
greatest historical disadvantage, (b) develop, enhance and maintain regional infrastructure and
cooperation, and (c) to make the countries in the region and the region as a whole more self-sufficient
in science and technology. The BENEFIT Secretariat is based in Namibia, while management
meetings are held on a rotating basis in Angola, Namibia and South Africa.
The launch of BENEFIT in April 1997 coincided with two major research cruises/surveys of the
Angola-Benguela Front which focused on fisheries and environment. (This front is situated west of
Angola and is thought to play an important role as a permeable internal "boundary" within the
BCLME, and demarcates the northern extent of pronounced coastal upwelling). During the past two
years BENEFIT increasingly gathered momentum with funding for priority projects being allocated
and real progress in human capacity development being made. Some recent achievements are briefly
as follows:
*
Several reports and scientific/technical papers have been published on the results of the 1997
Angola-Benguela Front surveys, and several regional scientists and technicians received hands
on training at sea, in the laboratory and in data analysis
*
A German sponsored BENEFIT Training Course was conducted in Namibia in 1997 and a
number of regional scientists received subsequent further training in Germany and in Norway
*
Fifteen fisheries and fisheries-environment (incremental) projects have been approved for
funding in 1999
*
Two training workshops have taken place (1998 and 1999) and a BENEFIT Training Plan to
complement the Science Plan is under development this year
*
In the first half of 1999 over 50 persons from the broad SADC region have been trained
during three BENEFIT cruises, including a 40-day survey of resources and the environment
which extended between Cape Town and Luanda, primarily funded by the African
Development Bank and The World Bank.
In addition to the above, strong links have been built between BENEFIT and three parallel (but
distinctly different) programmes, viz South Africa's established and internationally acclaimed
Benguela Ecology Programme (BEP), ENVIFISH (a three year European Union funded project
between seven EU states and Angola, Namibia and South Africa which focuses primarily on the
application of satellite data in environment-fisheries research and management, and which
commenced in October 1998) and VIBES (a bilateral French-South African initiative which focuses
on the variability of pelagic fish resources in the Benguela and the environment and spatial aspects of
the system - which also commenced in 1998). In all of these initiatives the emphasis is on science of
technology per se, and not on the much-needed transboundary management issues.
BENEFIT and related activities provide clear evidence of the desire and capability of Angola,
Namibia and South Africa to work together to solve common problems in the Benguela region in
partnership with the international community. This can form a strong base on which to develop
integrated management structures.
4
The Emerging BCLME Programme
The seed for the BCLME Programme was sown at the Workshop/Seminar on Fisheries Resource
Dynamics in the Benguela Current Ecosystem held in Swakopmund, Namibia, in May/June 1995 - the
same meeting which laid the foundation for BENEFIT. However, whereas BENEFIT focuses on
science and technology as applied to fisheries and the fish environment and science capacity
development, the focus of the BCLME Programme is different. In contrast to BENEFIT, the Benguela
Current LME programme is a broad based multi-sectoral initiative aimed at sustainable integrated
management of the Benguela Current ecosystem as a whole. It will focus on a number of key sectors
including fisheries and environmental variability, sea-bed mining, oil and gas exploration and
production, coastal zone management, ecosystem health and socio-economics and governance.
Transboundary management issues, environmental protection and capacity strengthening will be of
primary concern to the BCLME programme.
Inspired by the 1995 Workshop/Seminar and the progress being made on sustainable management of
other LMEs - the Black Sea LME in particular - and in order to develop a viable action plan to ensure
the sustainable management of the greater Benguela ecosystem, the three countries bordering the
Benguela (Angola, Namibia and South Africa) requested support from the Global Environmental
Facility, GEF, a fund established in 1991 under the management of The World Bank, the United
Nations Development Programme (UNDP) and the United Nations Environmental
Programme(UNEP)). An embryonic GEF/PDF Block B Grant application was developed by a small
group in late 1995, subsequently refined with the assistance of UNDP staff, and submitted to the GEF.
Following grant approval, US$344000 was made available by the GEF in 1998 to enable the
development of a comprehensive project proposal including the necessary instruments such as the
synthesis and assessment of information on the BCLME (contained in six comprehensive Thematic
Reports), a Transboundary Diagnostic Analysis (this document), Strategic Action Programme, and
Project Brief.
What Has Been Achieved?
Following the approval of the PDF Block B Grant a small Management Committee was established,
with members being appointed to represent the governments of the three countries, UNDP and some
donors. A Project Coordinator was appointed, based in Windhoek, Namibia, with logistical,
administrative and infrastructure support provided by the Namibian Ministry of Fisheries and Marine
Resources (as implementing agency) and administrative assistance by the UNDP Office in Windhoek.
In July 1998 the First Regional BCLME Workshop was held in Cape Town, which was followed by a
formal meeting of key stakeholders. The Workshop was attended by approximately 100 regional and
international experts and stakeholders representing a broad cross-section of the public and private
sectors in Angola, Namibia and South Africa. The following inter alia were among the organisations
in the three countries represented at the workshop:
From Angola: Ministry of Fisheries, Ministry of Environmental Affairs, Ministry of Science and
Technology, Augostino Neto University, TEXACO, National Oil Company(SONANGOL),
National Fishing Industry, Swedish International Development Agency (SIDA)
From Namibia: Ministry of Environment and Tourism, Ministry of Fisheries and Marine Resources,
Ministry of Agriculture Water and Rural Development, Ministry of Works Transport and
Communication, Ministry of Trade and Industry, Ministry of Mines and Energy,
NAMPORT, Meteorogical Service, BENEFIT Secretariat, Southern African Development
Community (SADC), Desert Research Foundation, National Petroleum Corporation of
Namibia (NAMCOR), Shell Exploration Namibia, Lalandii, UNDP, Namibian Minerals
Corporation (NAMCO), German Organisation for Technical Co-operation (GTZ).
From South Africa: Department of Environmental Affairs and Tourism, Department of Mineral and
Energy Affairs, National Parks Board, Cape Nature Conservation, Western Cape Provincial
5
Administration, Northern Cape Provincial Administration, SA Pelagic Fishing Industry
Association, SA Deep Sea Trawling Industry Association, University of Cape Town, Port
Nolloth Sea Farms, Eco-Africa, University of the Western Cape, SOEKOR, CSIR,
PORTNET, Ocean Diamond Mining, South-east Coast Inshore Fishing Association, Tuna
and Linefish Association, De Beers Marine, various consultancies.
(For further particulars and details of international participants, refer to Workshop documentation)
The workshop which was moderated by an independent international facilitator, generated a wealth of
information and ideas relevant to the development of a viable BCLME Programme. The objectives of
the Workshop were to identify issues and problems/constraints in the Benguela, to attempt to prioritise
these and propose possible solutions, to forge consensus among the various stakeholders and role-
players, to develop an implementable work plan and a mechanism for consultation and cooperation.
The success and output of this First Workshop can be gauged by the content of the Workshop Report
which is appended as a supporting document. At the Workshop keynote addresses were delivered on
other LMEs (Yellow Sea, Baltic, Bay of Bengal, Gulf of Guinea), the LME concept, International
Waters and the GEF and on various aspects of the Benguela per se viz the environment, fisheries, oil
and gas industries, mining, coastal zone management and pollution. These overviews provided useful
inputs for the subsequent group discussions from which the consensus on problems and priorities
emerged. The Stakeholders Meeting held after conclusion of the Workshop addressed issues such as
communication, the budget, donor involvement, studies/consultancies, project coordination and the
workplan.
Subsequent to the First Regional Workshop, consultants were appointed to prepare comprehensive
syntheses and assessments of information on the BCLME. This resulted in the production of six
Thematic Reports ("Integrated Overviews") on:
* Fisheries
*
Oceanography and Environmental Variability
* Diamond
Mining
* Coastal
Environments
*
Off-shore Oil and Gas Exploration/Production
*
Socio-economics of Some Key Maritime Industries
A Second Regional BCLME Workshop was held at Okahanjo near Windhoek, Namibia, during April
1999. At this Workshop the thematic reports were briefly reviewed. These syntheses, together with the
output from the First Workshop, served as a basis for the development of a draft Transboundary
Diagnostic Analysis (TDA). Many of those who had attended the First Regional BCLME Workshop
participated in the Second Workshop, and this provided a fair balance across the various stakeholders
in the three countries. Although there were necessarily fewer participants(40) all were either
acknowledged regional experts on the BCLME representing the main stakeholders or otherwise
international LME experts (refer to the Report of the Second Regional Workshop for more
comprehensive information). At the Workshop the participants divided into three groups to address
the three major issues in the BCLME, viz (1) utilization of resources, (2) environmental variability
and (3) ecosystem health and pollution. A breakdown of the sectoral and stakeholders involvement in
each of these three groups is appended at the back of this document. Excellent progress was made at
the Workshop thanks to quality of the leadership provided by the facilitator, the guidance by the
international representatives of UNDP-GEF and NOAA (LME concept) and the spirit of cooperation
and goodwill of the participants. The essential elements for the TDA were formulated (and prioritised)
as per the path: issues> problems> causes> impact> uncertainties> socio-economic consequences>
transboundary consequences> activities/solutions> priority> outputs> costs. This consensus
Workshop product forms the basis for the present TDA. Prior to the conclusion of the Workshop, the
framework for the Strategic Action Plan was defined and a Work Plan to finalise the BCLME project
development phase was formulated.
6
A small task team was appointed to draft a TDA document based on the output of the Second
Regional BCLME Workshop. The draft TDA was circulated to the members of the BCLME
Management Committee for comment in July 1999, and was revised so as to comply with GEFSEC
requirements and endorsed as a meeting of the Management Committee held in Cape Town on 30
September - 1 October 1999.
Towards a Sustainable Future: The Next Steps
What was clear by the end of the Second Regional Workshop was that an enormous amount of
goodwill, information and ideas has been generated within the region relevant to the sustainable
management of the Benguela Current ecosystem. This bodes well for the future and provides a strong
foundation, not only to develop a really viable LME approach to the Benguela Current region, but also
to provide a blueprint for how "convex" or open system LMEs should be developed internationally.
This contrasts the approaches for the existing predominantly "concave" or closed system LMEs that
have already been developed: In other words, sustainable integrated management of a highly variable
open-boundary ecosystem.
Correcting decades of over-exploitation of resources in the Benguela ecosystem and fragmented
management actions (the consequence of the colonial/political past and greed) will require a
substantial co-ordinated effort during the next decade, to be followed by sustained action on a
permanent basis. A task of this magnitude will require careful planning not only by the government
agencies in the three countries bordering the Benguela Current, but also by all the other stakeholders.
There already exists the willingness on the part of the key players to collaborate to achieve this
objective, but the real challenge will be to develop systems and structures that take cognisance of the
naturally highly variable and potentially fragile nature of the BCLME and its coastal environments
within the context of a changing society and world. The many issues and problems, as well as possible
solutions, have been identified and prioritised in the Transboundary Diagnostic Analysis tables. The
resolve of the governments of Angola, Namibia and South Africa to correct the wrongs of the past and
move forward with a new vision to ensure that the BCLME can be sustainably utilized and enjoyed by
future generations for the benefit of all is embodied in the elements of the Strategic Action Plan. This
Plan is much more than just a piece of paper: It is a pragmatic, workable framework and unambiguous
statement of common goals and objectives and the means of their achievement. Success will depend
on thorough implementation of the principles, commitments and actions embodied in the Plan, both
explicit and implicit.
In the TDA synthesis and analysis tables a number of major transboundary problems in the BCLME
have been identified. These include inter alia, non optimal harvesting of living resources, uncertainty
regarding ecosystem status and yields in a highly variable environment, deterioration in water quality,
habitat destruction and alteration, loss of biotic integrity and threat to biodiversity, harmful algal
blooms, introduction of alien species and inadequate regional capacity (human and infrastructure).
Over-arching generic actions which are needed to address these transboundary problems must focus
on capacity strengthening and training, policy development and harmonisation, and development of
regional collaboration or networking in respect of surveys and assessment of the ecosystem status.
These actions are appropriate within the context of a GEF project and it is envisaged that the role of
the GEF in the implementation phase of the BCLME Programme will take the form of institution
building, strengthening capacity needed in the region to facilitate integrated management, and sharing
the costs of the actions with the three governments and donors. The GEF should be catalytic in helping
to leverage sustainable (long term) funding and mobilise private sector funding. Through such a
process it is anticipated that, following the conclusion of the GEF funded BCLME component, the
necessary capacity and institutional structures and sustainable funding will be available in the region
to ensure the on-going integrated management of the BCLME. Specific actions in which the GEF will
play a role will include inter alia:
*
development of appropriate transboundary frameworks and mechanisms at regional, national
and local levels for consultation, coordination and cooperation
7
*
development of institutional capacities of the key agencies and institutions in the region that
contribute to the integrated sustainable management of the BCLME
*
effective ecosystem assessment and development of an early warning system for ecosystem
change
*
actions to fill the gaps in our understanding of the BCLME, its functioning, and the factors
which affect it (biophysical, social, economic and political)
*
harmonization of policies and legislation relating to activities affecting BCLME
*
increased external support for activities to minimise and mitigate the negative impacts of
development (mining, urbanisation, tourism development, resource exploitation) through the
promotion of sustainable approaches and the use of appropriate tools
*
measures to improve sustainable resource management
*
measures to protect biological diversity
*
quantification of the role of BCLME as a source/sink of CO2 and clarification of the role of
BCLME as a targeted early warning site for global change.
This is seen as compatible with the three elements of the GEF-funded International Waters activities
to meet incremental costs of:
1.
assisting groups of countries better understand the environmental concerns of their
international waters and work collaboratively to address them
2.
building capacity of existing institutions, or through new institutional arrangements, to utilize
a more comprehensive approach for addressing transboundary water-related environmental
concerns, and
3.
implementing sustainable measures that address priority transboundary environmental
concerns.
Policies, structures and actions developed during the implementation phase of the BCLME
Programme, i.e. over the next five years, must by the end of the period be self-sustainable in the
region. To achieve this it is essential that mechanisms be in place to encourage, indeed ensure, a
substantial degree of co-financing of activities. This can best be done by involving and developing
partnerships with maritime and coastal industries, the international community and present and future
beneficiaries, i.e. all those who have a stake in the long-term health and viability of the Benguela as a
LME.
8
USERS GUIDE TO THE TRANSBOUNDARY DIAGNOSTIC ANALYSIS (TDA)
Definitions and TDA Objective
A Transboundary Diagnostic Analysis is a scientific and technical assessment, through which the
water-related environmental issues and problems of a region are identified and quantified, their causes
analysed and their impacts, both environmental and economic, assessed. The analysis involves the
identification of causes and impacts (and uncertainties associated with these) at national, regional and
global levels, and the socio-economic, political and institutional context within which they occur. The
identification of the causes should, where appropriate, specify sources, locations and sectors. The
TDA assessment should indicate which elements are clearly transboundary in character and list and
prioritise activities or solutions to address the issue/problem and the root causes.
Within the context of the TDA, transboundary environmental issues include inter alia:
*
regional/national issues with transboundary causes/sources
*
transboundary issues with national causes/sources
*
national issues that are common to at least two of the countries and that require a common
strategy and collective action to address
*
issues that have transboundary elements or implications (e.g. fishery practices on
biodiversity/ecosystem resilience).
The objective of the Benguela Current TDA is to provide, on the basis of clearly established evidence,
structured information relating to the degradation and changing state of the Benguela Current LME, to
scale the relative importance of the causes and sources of the transboundary water-related problems,
and to elucidate practical preventative and remedial actions to ensure the sustainable integrated
management of this unique environment. The TDA provides the technical basis for the development
of a Strategic Action Plan (SAP), and the Project Brief, for the BCLME within the International
Waters Area of the GEF.
Design of the TDA
Comprehensive information about the status of the BCLME, the principal issues and problems, their
causes and impacts, generated at the First Regional BCLME Workshop in mid-1998 and through a
suite of Thematic Reports subsequently prepared by regional/international experts was examined at
the Second Regional BCLME Workshop (April 1999), synthesised and then condensed into a series of
analytical tables. These are presented in this document.
The current TDA has been designed at two operational levels. These are as follows:
(a)
Level One: Synthesis: The issues and perceived main transboundary problems, root causes
and areas where action is proposed
This level, consisting of a Synthesis Matrix and some explanatory text about the transboundary
characteristics of the BCLME serves as a logistical "map" for the TDA. It considers the main issues
and major perceived environmental problems which must be addressed for the sustainable integrated
management of the BCLME. It examines the transboundary elements of the problems (i.e. elements
shared by at least two of the three countries) and then relates them to their major underlying
institutional, societal or global root causes. In all cases the root causes are common to a large number
of problems and require changes to the role given to environmental issues within the priorities of the
governments and the public in general. The matrix identifies three generic areas (issues) where
proposals for action can be formulated, viz utilization of resources, environmental variability and
pollution/ecosystem health. For each of these generic areas a number of more specific issues ("sub-
9
issues") are identified. These are extensively developed at the next level of the TDA. A simplified
version of the Synthesis Matrix is given in Fig.2.
(b)
Level Two: Specifics: Comprehensive information on the issues, sub-issues, problems,
causes, impacts, uncertainties, socio-economic consequences, the perceived solutions,
priorities, outputs and costs
Working on the basis of the issues and major problems perceived in Level One, the tables and text
which comprise Level Two examine the nature of the specific problems identified as contributors to
ecosystem degradation and change in the Benguela Current region. They examine the management
uncertainties (in the case of environmental variability, the uncertainty of the variability per se) and
knowledge gaps which need to be filled. They present priority practical and implementable proposals
for inclusion in the BCLME SAP and the cost of the required international action where possible.
Finally the series of tables identify the outputs (products) which should be obtained through the
successful implementation of the action and lists the stakeholders for each problem and action area
identified. Explanatory text is provided for each sub-issue table.
More Information
Readers requiring more information about the BCLME, present state of knowledge about ecosystem
structure and functioning, its complexity, ecosystem status, ongoing work and principal management
problems are referred to the following:
*
Report on the First Regional BCLME Workshop (73pp)
*
Report on the Second Regional BCLME Workshop (72pp)
*
Background Papers for the First Regional BCLME Workshop
*
Synthesis and Assessment of Information on the BCLME: Thematic Reports 1-6
*
Proceedings of the International Symposium on Environmental Variability in the South-east
Atlantic, March/April 1998 (approx 600pp)
*
Proceedings of the Workshop on Environmental Variability, Environmental Monitoring and
Environmental Strategic Planning, April 1998 (28pp)
*
The Benguela and Comparable Ecosystems (South African Journal of Marine Science, Vol.5,
1987: 957pp)
*
Benguela Trophic Functioning (South African Journal of Marine Science, Vol.12, 1992:
(1108pp)
* Benguela
Dynamics
(South African Journal of Marine Science, Vol.19, 1999: 512pp)
10
BCLME TRANSBOUNDARY DIAGNOSTIC ANALYSIS
Geographic Scope & Ecosystem Boundaries
Conducting a comprehensive transboundary analysis is only possible if the entire LME, including all
inputs to the system, is covered in the study. In the case of the Benguela, which is a very open system
where the environmental variability is predominantly remotely forced, this should then include the
tropical Atlantic sensu latu, the Agulhas Current (and its link with the Indo-Pacific) the Southern
Ocean and the drainage basins of all major rivers which discharge into the greater Benguela Current
region including the Congo River. Clearly such an approach is impracticable, and more realistic and
pragmatic system boundaries have to be defined in order to develop and implement a viable ecosystem
management framework. The principal external and internal system boundaries are shown in Fig.1.
*
Landward boundary: With the exception of the Congo River, the main impact of discharges
from rivers flowing into the South-east Atlantic tends to be episodic in nature, i.e. in terms of
significant transboundary concerns, these are limited to extreme flood events. (Their drainage
basins nevertheless do include a major part of the southern African hinterland). The Congo
River, however, exerts an influence which can be detected over thousands of kilometers of the
South Atlantic and drains much of Central Africa. From a practical poing of view, it is quite
beyond the scope of the BCLME to attempt to include the development of any management
structures for a river such as the Congo. With respect to land sources of pollution in the
BCLME (excluding the Congo River area), these are only really significant in the proximity of
the principal port-cities, e.g. Cape Town, Luanda, Walvis Bay, and the effects are generally
very localised. Nevertheless, some of the problems experienced in these areas are common in
nature and could be addressed through similar remedial actions. Like coastal development,
their impacts generally do not have a transboundary character. (Pollution from ships, major oil
spills, introduction of alien species and associated harmful algal blooms, etc. are, in contrast,
transboundary concerns). From a BCLME perspective, the landward boundary can thus, for all
practical purposes, be taken as the high water mark at the coast. Specific allowances can be
made in some areas on a case by case basis (e.g. during episodic flooding from the Orange and
Cunene Rivers which are situated at the country boundaries of South Africa-Namibia and
Namibia-Angola respectively).
*
Western boundary: The Benguela Current is generally defined as the integrated equatorward
flow in the upper layers of the ocean in the South-east Atlantic between the coast and the
00meridian. The BCLME Programme will accordingly use 00 as the western boundary, but for
practical management purposes the focus will be on the areas over which the three countries
have some jurisdiction, i.e. their Exclusive Economic Zones which extend 200 nautical miles
seawards from the land.
*
Southern/eastern boundary: The upwelling area of the BCLME extends around the Cape of
Good Hope, seasonally as far east as Port Elizabeth. This extreme southern part of the
ecosystem is substantially influenced by the Agulhas Current, its Retroflection (turning back)
and leakage of Indian Ocean water into the Atlantic south of the continent. As the variability
of the BCLME is very much a function of the complex ocean processes occurring in the
Agulhas Current - Retroflection area, this will be taken as the southern boundary with 270E
longitude (near Port Elizabeth), being at the extreme eastern end.
*
Northern boundary: While the Angola-Benguela Front (more correctly a series of fronts)
comprises the northern extent of the main coastal upwelling zone, upwelling can occur
seasonally along the entire coast of Angola. There are, in any event, strong linkages between
the behaviour of the Angola-Benguela Front (and the oceanography of the area to the south of
it) and processes occurring off Angola, especially the Angola Dome and the Angola Current.
Unless these are considered as an integral part of the BCLME, it will not be feasible to evolve
11
a sustainable integrated management approach for the Benguela. Moreover, there is a well-
defined front at about 50S, viz the Angola Front which is apparent at sub-surface depths. It is
this front which is the true boundary between the Benguela part of the South Atlantic and the
tropical/equatorial Gulf of Guinea system. A northern boundary at 50S would thus encompass
the Angola Dome, the coastal Angola Current and the area in which the main oxygen
minimum forms and the full extent of the upwelling system in the South-east Atlantic. A
pragmatic northern boundary is thus at 50S latitude, which is in the vicinity of the northern
boundary of Angola (Cabinda) and the southern extent of the Gulf of Guinea Large Marine
Ecosystem(GOGLME). Strong links will need to be built between the BCLME and the
GOGLME (and other initiatives in the tropical Atlantic) in order to develop an eventual
holistic approach to the management of the South-east Atlantic Ocean.
Level One: Synthesis: The Issues and Perceived Main Transboundary Problems, Root Causes
and Areas where Action is Proposed
Seven perceived major transboundary problems have been identified. These are listed below, together
with a short description of the transboundary characteristics of each of them. The Synthesis Matrix or
"logistical map" and Fig.2 which then follow the description encapsulate the essence of the TDA.
They highlight the transboundary elements and root causes associated with each problem and
schematically show how the proposed actions serve to address the causes and help solve the problems:
Problem (i): Decline in BCLME commercial fish stocks and non-optimal harvesting of living
resources
Transboundary Characteristics: Country boundaries do not coincide with ecosystem sub-boundaries;
most of the regions' important harvested resources are shared between countries, or move across
national boundaries at times. Over-harvesting of a species in one country can therefore lead to
depletion of that species in another, and in changes to the ecosystem as a whole. Moreover, many
resource management difficulties are common to all the countries.
Problem (ii): Uncertainty regarding ecosystem status and yields in a highly variable environment
Transboundary Characteristics: The Benguela environment is highly variable and the ecosystem is
naturally adapted to this. However, sustained large scale environmental events such as Benguela
Niños, episodic hypoxia/anoxia, Agulhas intrusions and changes in winds, affect the ecosystem as a
whole, compounding the negative effects of fishing. These events and changes generally have their
origin and cause outside of the BCLME, but are of such a scale that the impacts occur in ther
international water areas of all three countries i.e. the changes propagate across external BCLME
boundaries and internal geopolitical boundaries. The poor ability to predict the events and change
limits the capacity to manage effectively system wide. In addition the BCLME is believed to play a
significant role in global ocean and climate processes and may be an important site for the early
detection of global climate change.
Problem (iii): Deterioration in water quality - chronic and catastrophic
Transboundary Characteristics: Although most impacts of chronic deterioration in water quality are
localised (national issues), they are common to all of the countries and require collective action to
address. Moreover, chronic pollution can favour the development of less desirable species, and result
in species migration. Catastrophic events (major oil spills, maritime accidents) can impact across
country boundaries, requiring co-operative management and sharing of clean-up equipment and
manpower.
Problem (iv): Habitat destruction and alteration, including inter alia modification of seabed and
coastal zone and degradation of coastscapes
Transboundary Characteristics: Although most impacts may appear localised, habitat alteration or
loss due to fishing and mining can cause migration of fauna and system-wide ecosystem change.
Uncertainties exist about the regional cumulative impact on benthos resulting from mining and
associated sediment re-mobilisation. Moreover, certain mining activities are conducted close to
12
national boundaries and negative consequences may be transmitted across into the adjacent country's
EEZ. Inadequately planned coastal developments result in degradation of coastscapes and reduce the
regional value of tourism.
Problem (v): Loss of biotic integrity (changes in community composition, species and diversity,
introduction of alien species, etc.) and threat to biodiversity/endangered and vulnerable species
Transboundary Characteristics: Most harvested fish species are shared between countries and
straddle geopolitical boundaries. Past over-exploitation of targeted fish species has altered the
ecosystem as a whole, impacting at all levels, including on top predators and reducing the gene pool.
Some species, e.g. African penguin, are threatened or endangered. Exotic species have been
introduced into the Benguela. (This is recognised as a global transboundary problem).
Problem (vi): Inadequate human and infrastructure capacity to assess the health of the ecosystem as a
whole (resources and environment, and variability thereof)
Transboundary Characteristics: There is inadequate capacity, expertise and ability, in the region to
monitor and assess adequately the shared living resources and system-wide environmental variability.
Moreover, there is unequal distribution of this capacity between the three countries.
Problem (vii): Harmful algal blooms (HABs)
Transboundary Characteristics: HABs occur in all three countries, who face similar problems in
terms of impacts and management, and which require collective regional action to address.
13
Benguela Current Transboundary Diagnostic Analysis
Transboundary Diagnostic Analysis
(TDA)
LEVEL ONE
Synthesis Matrix
14
SYNTHESIS MATRIX
Perceived Major Problem
Transboundary Elements
Major Root
Activity
Causes
Areas
Decline in BCLME
Most of the regions important
1,2,3,4,5,6,7 A,B
(C)
commercial fish stocks
harvested resources are shared
and non-optimal
between countries, or move
harvesting of living
across national boundaries at
resources
times, requiring joint
management effort
Uncertainty regarding
Environmental
1,2,3,7 A,B,C
ecosystem status and
variability/change impacts on
yields in a highly variable
ecosystem as a whole, and
environment
poor predictive ability limits
effective management. The
BCLME may also be important
to global climate change
Deterioration in water
While most impacts are
2,3,4,5,7 C
quality - chronic and
localised, the problems are
catastrophic
common to all three countries
and require collective action to
address
Habitat destruction and
Uncertainties exist about the
2,3,5,6,7 A,C
(B)
alteration, including inter
regional cumulative impact
alia modification of seabed from mining on benthos and
and coastal zone and
ecosystem effect of fishing.
degradation of coastscapes Degradation of coastscapes
reduce regional value of
tourism
Loss of biotic integrity*
Fishing has altered the
1,3,5,6 A,C
(B)
and threat to biodiversity/
ecosystem as a whole, reduced
endangered and
the gene pool, and caused
vulnerable species
some species to become
endangered or threatened.
*Changes in community
Introduced alien species are a
composition, species
global transboundary problem
diversity, introduction of
alien species etc.
Inadequate capacity to
There is inadequate capacity in 1,2,5,7 A,B,C
assess ecosystem health
the region to assess the shared
(resources and
resources and the system-wide
environment, and
environmental variability, and
variability thereof)
unequal distribution of the
capacity between countries
Harmful algal blooms
HABs are a common problem
1,2,3,6,7 A,B,C
(HABs)
in all three countries and
require collective action to
address
Level Two: Action Areas: An Overview of Specific Transboundary Problems, Causes, Impacts,
Actions Required and Anticipated Outputs
In Level One: Synthesis, three broad action areas were identified in order to address the perceived
major BCLME problems and the main root causes of these problems. The action areas correspond to
the three main issues in the BCLME, namely utilization of resources, environmental variability, and
ecosystem health and pollution. For each action area a set of more specific actions was specified in the
Synthesis Matrix. These specific actions were formulated collectively through consensus among
stakeholders at the Second Regional BCLME Workshop to identify the specific problems associated
with each main issue. These have been prioritised and the outputs or solutions emanating from the
specific actions have been listed and costed. The essential information has been summarised in the set
of analysis tables which follow. These tabular summaries are necessarily brief - often in point form -
and where additional clarification has been deemed necessary, this has been provided following each
table in the form of explanatory notes.
What is not immediately apparent from the Level Two tables which were developed by consensus at
the Second Workshop is that there are a number of generic actions which cut across the specific
actions within each of the three broad action areas, and indeed even between the broad action areas.
For the sake of completeness the essence of this alternative but complementary approach is as follows:
Action Area A: Sustainable management and utilization of resources
Generic Actions:
* Capacity strengthening and training
Joint surveys and assessments of shared resources and intercalibration
Policy harmonization and integrated management
Co-financing with private sector/industry
Development of new industries (e.g. mariculture, tourism)
Action Area B: Assessment of environmental variability, ecosystem impacts and improvement of
predictability
Generic Actions:
* Capacity strengthening and training re transboundary concerns
Regional networking and international linking
Development of regional early warning system, assessment and
prediction capability (including re-assessments) and joint response
policies
Cross-cutting demonstration projects
Action Area C: Improvement of ecosystem health and management of pollution
Generic Actions:
* Capacity strengthening and training
Policy harmonization, and development
Development of regional framework for assessment
Establishment of effective surveillance and enforcement agencies
Development of stakeholder participation structures
What emerges quite clearly from the above approach is that generic actions, such as capacity
strengthening and training, the development of regional collaboration or networking in respect of
surveys and assessments, and policy development and harmonization, are over-arching actions. These
are obvious priorities for GEF support.
15
Benguela Current Transboundary Diagnostic Analysis
Transboundary Diagnostic Analysis
(TDA)
LEVEL TWO
Analysis Tables and Explanatory Notes
Note: The numbering of these tables corresponds with the action areas identified in the Level One
Synthesis Matrix
16
BENGUELA CURRENT LARGE MARINE ECOSYSTEM
PROGRAMME
TRANSBOUNDARY DIAGNOSTIC ANALYSIS TABLES
TABLE A 1-5
Sustainable Management and Utilization of Resources
A1
Facilitation of Optimal Harvesting of Living Resources
A2
Assessment of Mining and Drilling Impacts and Policy Harmonization
A3
Responsible Development of Mariculture
A4
Protection of Vulnerable Species and Habitats
A5
Assessment of Non-Harvested Species and their Role in the Ecosystem
TABLE B 1-3
Assessment of Environmental Variability, Ecosystem Impacts and
Improvement
of
Predictability
B1
Reducing Uncertainty and Improving Predictability
B2
Capacity Strengthening and Training
B3
Management of Consequences of Harmful Algal Blooms
TABLE C1-5
Maintenance of Ecosystem Health and Management of Pollution
C1
Improvement of Water Quality
C2
Prevention and Management of Oil Spills
C3
Reduction of Marine Litter
C4
Retardation/Reversal of Habitat Destruction/Alteration
C5
Conservation
of
Biodiversity
17
Main Root Cause
1 Complexity of ecosystem and high degree of
·
Changing state of the Benguela
variability (resources and environment)
·
Inadequate information and understanding
·
Difficulty in monitoring and assessment
·
Poor predictability
·
Colonial/political past
2 Inadequate capacity development (human and
infrastructure) and training
·
Institutional downsizing and braindrain
·
Limited inter-country exchange (training)
·
Regionally incompatible laws and regulations
3 Poor legal framework at the regional and
national levels
·
Ineffective environmental laws and regulations
·
Inadequate compliance and enforcement (over
4 Inadequate implementation of available
fishing, pollution)
regulatory instruments
·
Indifference and poor communication
·
Posts not filled (some inappropriately)
5
·
Inadequate intersectoral coordination
Inadequate planning at all levels
·
Poorly planned coastal developments
·
Limited time horizon of planners
·
Rapid urbanisation and informal settlements
·
Lack of awareness and public apathy
6 Insufficient public involvement
·
Conflicts about rights of access
·
Low country GDPs
7 Inadequate financial mechanisms and support
·
Ineffective economic instruments
·
Insufficient funding for infrastructure and
management; poor salaries
Areas Where Action is Proposed
A Sustainable management and utilization of
·
Facilitation of optimal harvesting of living resources
resources
·
Assessment of mining and drilling impacts and policy
harmonization
·
Responsible development of mariculture
·
Protection of vulnerable species and habitats
·
Assessment of non-harvested species and role
B Assessment of environmental variability,
·
Reducing uncertainty and improving predictability
ecosystem impacts and improvement of
·
Capacity strengthening and training
predictability
·
Management of consequence of harmful algal blooms
C Maintenance of ecosystem health and
·
Improvement of water quality
·
Prevention and management of oil spills
management of pollution
·
Reduction of marine litter
·
Retardation/reversal of habitat destruction/alteration
·
Conservation of biodiversity
19
GENERIC ROOT CAUSES
Inadequate capacity
Poor legal
Inadequate
Inadequate planning
Insufficient public
development (human
implementation of
at all levels
involvement
framework at the
and infrastructure)
regional and national
available regulatory
and training
levels
instruments
Complexity of
Inadequate financial
MAJOR TRANSBOUNDARY PROBLEMS
ecosystem and high
mechanisms and
degree of variability
support
·
Decline in BCLME commercial fish stocks and non-
optimal harvesting of living resources
·
Uncertainty regarding ecosystem status and yields in a
highly variable environment
·
Deterioration in water quality - chronic and catastrophic
·
Habitat destruction and alteration, including inter alia
modifications of seabed and coastal zone and
degradation of coastscapes
·
Loss of biotic integrity and threat to biodiversity
·
Inadequate capacity to assess ecosystem health
· Harmful algal blooms
Sustainable
Assessment of
Maintenance of
management and
environmental
ecosystem health
utilization of
variability,
and management of
resources
ecosystem impacts
pollution
and improvement of
predictability
20
AREAS WHERE ACTION IS REQUIRED
Fig 2 Major transboundary problems, generic root causes and areas requiring action
TABLES A: SUSTAINABLE MANAGEMENT AND UTILIZATION OF RESOURCES
TABLE A1: FACILITATION OF OPTIMAL HARVESTING OF LIVING RESOURCES
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-
TRANS-
ACTIVITIES/
PRIORITY
INCRE-
ANTICIPATED
UNCERTAINTIES
ECONOMIC
BOUNDARY
SOLUTIONS
MENTAL
OUTPUTS
CONSEQUENCES
CONSEQUENCES
COST (5y)
A1. Non optimal
· Fishing
· High by-catch
· Irreversible
· Variable and
· Most harvested
· Provision of
1
$ 500 000
· Optimal
harvesting of
overcapacity
& undersize
ecosystem change
uncertain job
resources are
information:
sustainable
living resources:
· Inadequate
catch
· Biodiversity
market
shared between
to facilitate
resource
Non optimal
tools
· Fisheries
Change
· Loss of national
countries or cross
regional
utilization
harvesting
· Non-
impacting
· Habitat destruction
revenue
national borders.
assessments
· Improved
includes over
sustainable
productivity
· Collapse of
· Lack of food
Over fishing in
of shared
forecasting
harvesting, such as
utilization of
cycle
commercially
security: artisanal
one country can
resources
· Establishment
overfishing, as
resources
· Ecosystem
important stocks
/industrial
cause depletion in
and
1
of a regional
well as wastage
· Lack of
change
· Erosion of
neighbour country.
ecosystem
$ 2 000 000
forum
through dumping
collaborative
· Resource
sustainable
· Common problems
impacts.
1
· Prevention of
of bycatch and the
assessment
depletion
livelihoods
· Shared solutions
· Joint surveys
$ 400 000
irresistable
catching and
and
· Human
· Missed
and
ecosystem
dumping of under-
monitoring
population
opportunities
assessments
change
size fish. It also
· Inadequate
movements
(under-utilization
· Gathering
1
includes not taking
information
(local &
& wastage)
and
$ 400 000
advantage of
· Inadequate
regional)
· Loss of
calibration of
resources with the
management
· Large variation
competitive edge
baseline
potential to offer
· Inadequate
in landings
on global
information
sustainable
control
· Variation in
markets
· Analysis of
2
development
·
$ 1 000 000
Lack of
food supply for
socioeconom
opportunities (e.g.
birds, seals etc.
ic
seaweed, some
collaborative
·
consequence
1
invertebrates).
management
Conflict (e.g.
$ 800 000
of shared
artisanal vs.
s for the
This often results
whole
from a lack of
resources
commercial vs.
ecosystem
technology or
· International
recreational;
conflict with
· Assessment
knowledge of the
policy on
of potential
opportunities
seal
mining)
of new
available.
harvesting
· Exploding seal
resources
population
· Establish a
· Competition for
regional
exploited
forum for
resources
stock
assessment,
ecosystem
assessment
and annual
advice
21
A1 EXPLANATORY NOTES. PROBLEM: NON-OPTIMAL HARVESTING OF LIVING RESOURCES
Causes
·
Fishing overcapacity Too many fishers, too many boats, excess processing capacity.
·
Inadequate tools for assessment Currently available tools for assessment do not always produce effective results, data for assessment are not equally available and are not in a uniform format.
Assessment tools that are available are not applied equally within the region, and fishing methods are not sufficiently selective.
·
Non-sustainable utilization of resources due to overfishing, high bycatch, catches of small fish and non-targeted species. This is a tradition in worldwide fisheries management.
·
Lack of collaborative assessment and monitoring there is no effective mechanism within the region to ensure that collaborative assessment takes place.
·
Inadequate information the biology of all harvested and potentially harvested species is not always well known. In the latter, some groups with economic potential, such as seaweeds and some
invertebrates, are very poorly known within the region.
·
Inadequate management management due to insufficient information, vulnerable to pressure from industry, over-riding socioeconomic and political pressures. Lack of informed advice
sometimes results in ill-advised management decisions.
·
Inadequate control even when assessments and quotas are used to manage fisheries, the control and enforcement mechanisms are often lacking
·
Lack of collaborative management of shared resources.
·
International policy on seal harvesting Conservation pressure on national governments prevents utilization of seals, and contributed to the increase in seal populations, with implications for
other components of the ecosystem.
Impacts
·
Resource depletion This is an obvious effect of over-harvesting, a depletion of the resource below optimal levels.
·
High bycatch & undersize fish catch This reduces the productivity of fisheries, and may lead to ecosystem change (uncertainty) and decreased yields.
·
Fisheries impacting productivity cycle The depletion of, for example, a grazer such as pilchard from the system could cause the diversion of production into eutrophication with subsequent
sulfur eruptions that might kill off zooplankton grazers and further shift the system out of balance. Changes in the system could reduce yields in other ways too, e.g. changes that favour large
gelatinous plankton. Recruitment fisheries result in productivity and yields that are less than what they could be under better management.
·
Ecosystem change Over-harvesting of ecologically important species may change the nature of the ecosystem, such as diverting productivity into decompositional pathways that may lead to
increases in frequency/intensity of anoxic event (S.Afr. J. Mar Sci. 12)
·
Human population migration (local & regional) Declines in opportunities in resource harvesting at the coast leads to increased migration into cities, and the expansion of urban poverty,
exacerbated by large slumps in catches.(BCLME Thematic Report 6)
·
Large variation in landings results should be precautionary approach leading to reduced levels of over-harvesting. Regularity of employment, reliability of markets, etc. all suffer when
variation is great.
·
Variation of food supply for birds, seals etc. Humans and other organisms compete for food. Over-harvesting of resources by humans may lead to a decrease in food supply available to
seabirds, seals, and other marine organisms that may themselves be important as tourism resources (S.Afr. J. Mar Sci. 12).
·
Conflict (e.g. artisanal vs. commercial vs. recreational) Artisanal, recreational and commercial fishers often compete for the same resources. Conflicts among these sectors may increase when
resource become depleted.
·
Exploding seal population.
·
Competition for exploited resources harvesting of pelagic resources has had a huge impact on food availability for other top predators.
Risks/uncertainty
·
Irreversible ecosystem change The degree to which changes that take place in the ecosystem (as a result of over-harvesting) are reversible, is not known.
·
Biodiversity change Changes in biodiversity (genetic, species, ecosystem) may occur as a result of the over-harvesting of resources, but the lack of good baseline data makes this difficult to
assess. Hence we do not know the degree to which overfishing affects biodiversity.
·
Habitat destruction The degree to which over-harvesting affects habitat through impacts on dominant species, or directly through impacts of the harvesting technology (e.g. bottom trawls) is
unknown. Baseline data are lacking.
·
Actions in one country can cause collapse of a shared commercially important stock(eg. Collapse of Benguela hake stock in 1970s as result of gross overfishing by foreign fleats)
22
Socioeconomic consequences
·
Financial & job numbers Over-harvesting of resources reduces the number of jobs and the financial gain accruing to coastal communities. Jobs lost in one country may result in an increase in
job opportunities in another country due to changes in employment opportunities.
·
Loss of national revenue If resources are over-harvested, or if opportunities to developing new resources on a sustainable basis are missed, then the contribution of those resources to the
national revenue base is reduced.
·
Lack of food Security (artisanal/industrial) artisanal fishers depend on fisheries resources directly for protein; over-harvesting by the industrial sector may erode the food security of coastal
artisanal fishers and their families. Loss of jobs in the industrial sector may also increase poverty, and decrease food security.
·
Erosion of Sustainable livelihoods livelihoods of coastal people may often depend on activities that are based on assets (e.g. fish resources) that are harvested by other sectors. Over-
harvesting of those assets, either by coastal dwellers themselves or by industrial harvesting, may erode the livelihoods of coastal people, and bring about increased urban migration and increases
in urban poverty and the spreading of poverty-related diseases.
·
Missed opportunities (under-utilization & wastage) There may be many opportunities for the novel utilization of marine resources. Examples include drugs from both inshore and deep-water
invertebrates, as well as drugs and other low-volume, high-value products from seaweeds. A coordinated regional assessment of such resources and coordinated development could bring
regional benefits in this area.
·
Competitive edge on global markets Lost markets are difficult to regain, could have global impacts (retain dominating role in hake market, regain role in fishmeal market). Increases or
reductions in yields in one area may impact upon another area (country), resulting in market competition among the BCLME countries. To retain a competitive edge in rapidly changing
markets, stability of the throughput and quality enhancement that comes with that stability are essential.
Transboundary consequences
·
Most of the regions important harvested resources are shared between countries(i.e. stradle national boundaries), or move across national boundaries at times. (See Oceanogr. Mar Biol. Ann.
Rev. Vol 25, pp 353 505, and also BLCME Thematic Report 1). Over-harvesting of a species in one country can therefore lead to depletion of that species in another, and in changes to the
ecosystem as a whole. (For example the collapse of the Namibian sardine in the 1970's followed the collapse of the sardine in South African waters)
·
Inappropriate management of regional resources endangers sustainability of resources and consistency of catches, and leads to sub-optimal use. Lower food production, loss of jobs & national
revenue, and increase reliance on foreign aid.
·
Potential irreversible changes in nature of ecosystem due to depletion of widely distributed ecologically important species. (S.Afr. J. Mar. Sci 12)
·
Movement of vessels and humans across borders in response to depletion of resources. Increased local and regional conflicts. (Refer to ICSEAF reports)
·
Depletion and/or large-scale distributional shifts in predator species in response to reduced prey abundance. (see S.Afr. J. Mar. Sci 12) For example there is evidence that Namibian seals
population was severly depleted and some animals migrated into Angola and South African waters following the 1995 Benguela Niño.
Activities/solutions
·
Co-financing with industry Co-financing from the fishing industry and other donors is a priority for effective management.
·
Provision of information to facilitate regional assessments of shared resources. This will be argumented by BENEFIT ouputs(co-financed). A structure should be established to conduct
regional stock assessments, ecosystem assessments, evaluate resource-environmental linkages, and facilitate post-harvest technology.
·
Joint surveys & assessments Carried out cooperatively will help produce enhanced management and optimal utilization. These joint surveys will be offered as a 5-year demonstration of the
benefits to the individual nations of joint transboundary assessments.
·
Gathering and calibration of baseline information - This should be done on resources, potential resources before harvest, as well as ecosystems.
·
Cooperative analysis of socioeconomic consequences - Analyses of the socioeconomic consequences of non-optimal and improved use of resources should be done with a view to appropriate
intervention within the framework of improving sustainable livelihoods.
·
Cooperative training - Cooperative training will be essential to generate regional capacity needed to address the transboundary issues, and to promote sustainable intergrated management.
Cooperative training targeted at communities will so be necessary. Training in management, enforcement, and the creation of new opportunities.
·
Cooperative assessment of potential new transboundary resources. Many biological resources and potential new resources in both offshore and inshore areas are common to the BCLME, and
assessments should be conducted cooperatively.
Priority
·
Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those activites which address transboundary problems requiring incremental funding are listed.
23
Anticipated outputs
·
Optimal resource utilization This is the most obvious output from the suggested solutions; there will be a reduction in the exploitation level of resources that are deemed to be over-harvested
so that stocks can be rebuilt to optimum levels, and an increase in the benefit to coastal communities from the improved utilisation of resources.
·
Improved forecasting Joint assessment will enable improve predictions of sustainable resource-harvest levels.
·
Establish regional structure This regional structure will be responsible for producing annual stock assessment reports, annual ecosystem reports, and provide advice or suggestions of resource
harvesting levels, and other matters related to resource use, particularly fisheries.
· Training packages on management, enforcement, and opportunity creation all at the regional level to advance the concept of susatinable intergrated management of the BLCME.
24
TABLE A2: ASSESSMENT OF MINING AND DRILLING IMPACTS AND POLICY HARMONIZATION.
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-ECONOMIC
TRANS-
ACTIVITIES/
PRIORITY
INCRE-
ANTICIPATED
UNCERTAINTIES
CONSEQUENCES
BOUNDARY
SOLUTIONS
MENTAL
OUTPUTS
CONSEQUENCES
COST
(5y)
A2. Mining and
· Pipelines
· Habitat destruction
· Cumulative impacts
· Financial &
· hree countries
· Policy
1
$ 100 000
· Environmental
drilling impacts:
· Drilling &
· Seabed modification
· Effects on benthos
employment benefits
share common
harmonizatio
management
Exploration for
dredging
· Coastal soil, beach,
· Change of bio-
· -ve: exclusion
problems
n
2
[$ 100
plan
oil and gas and
· Seismic
intertidal and subtidal
diversity
+ve: reserves
· Cumulativects
· Enhanced
000]
· Integrated
minerals such as
exploration
profile destruction
· Cost/ benefit
· Reduced artisanal
impacts are
consultation
management
diamonds is
· Conflicts (fish,
fisheries
unknown but may
sectoral and
· Solution to
expanding
diamonds, gas)
· Coastal tourism
be substantial
regional
1
capacity
throughout the
· Behaviour of
· Onshore development · Shared solutions
· Cumulative
$ 500 000
problem
Benguela. This
resources
· Effects on coastal
impact
[$ 500
involves drilling,
· Mortality of larvae
communities, post-
assessment
000]
dredging and
mining
for BCLME
industry
seismic
exploration.
There is
substantial oil
extraction in
northern Angola
(Cabinda) while
the development
of oil/gas fields
(with pipelines)
are planned
further south
(e.g. Namibia).
Capped
wellheads
hamper fishing
while drill
cuttings and
hydrocarbon
spills impact on
the environment.
Extensive
diamond mining
is being
conducted using
dredging
equipment along
the coasts of and
continental
shelves of
Namibia and
South Africa.
Ecosystem
effects of these
activities are not
fully known.
25
26
A2 EXPLANATORY NOTES. PROBLEM: MINING AND DRILLING IMPACTS
Causes
·
Pipelines
·
Drilling & dredging
·
Seismic exploration
Impacts
· Habitat destruction Habitat destruction from drilling may be localized, but dredging for diamonds
disrupts large areas of seabed, disturbs the sediments and changes the particle size distribution. The
impact of this on benthos and other resources, particularly fisheries resources, needs to be assessed
and mitigated if necessary.
· Seabed modification Seabed modification, related to habitat destruction, may impact on the
exploitation of other resources; for example, pipelines and wellheads and their potential impact on
availability of bottom areas to trawl fishing.
· Coastal soil, beach, intertidal and subtidal profile destruction. Coastal mining moves the coastal soils,
alters the beach profile and destroys coastal vegetation, and intertidal and subtidal habitats.
· Conflicts (fish, diamonds, oil & gas). Conflicts may arise between different sectors. Appropriate
strategies are needed to decrease the potential for conflict, and to resolve conflicts that arise (e.g.
lobster / diamond, fishing / oil).
· Behaviour (e.g. scaring of mammals and fish during seismic surveys) & mortality (e.g. mortality of
larvae) of resources Fish migrating away from, and fish larvae being killed by activities.
Risks/uncertainty
· Cumulative impacts The cumulative impacts of lots of smaller impacts from mining, as well as the
cumulative effects over time, are unknown, but may be significant within the context of the
ecosystem.
· Effects on benthos The effects of mining on benthic communities are uncertain.
· Change of biodiversity It is not known whether mining impacts lead to a reduction in biodiversity in
the mined areas
· Cost/benefit Costs and benefits to the environment from mining and drilling in this perspective are
unknown.
Socioeconomic consequences
· Negative: Exclusion zones around mining operations, wellheads on Agulhas Bank
Positive: Reserves A negative effect of mining is the closure of large areas of coastline, restricting
access to living resources by coastal dwellers or potential dwellers. A positive effect is that exclusion
zones could act as biotic reserves.
· Reduced artisanal fisheries - This is a negative effect of the exclusion, as well as the impact of
mining-related coastal activities.
· Coastal tourism The closure of large areas of coast reduces the potential for tourism development in
affected areas.
· Onshore development Onshore development increases opportunities for jobs, but also modifies
habitats through construction and pollution. In addition, coastal migration, urbanization and poverty
may be an impact where open towns are adjacent to mining areas.
· Effects on coastal communities post mining - Mines eventually close, leaving former mine workers
without obvious sources of sustainable employment.
Transboundary consequences
· Mining activities occur in all three countries (see BCLME Thematic Reports 3 and 5). Most of the
impacts are localized but uncertainty exists regarding cumulative impacts of oil/gas and diamond
27
mining which added to impacts of fishing and pollution could be significant, especially regarding
benthos. As such as assessment of the cumulative impacts of mining/drilling is a prerequisite for
sustainable intergrated management of the BCLME.
· The mining industry in RSA, Namibia and Angola undertake EIA's for all projects. The oil/gas and
diamond industry in RSA and Namibia are working together to consolidate baseline information.
This results in an apreciable level of co-financing.
· All three countries share common problems. For example, conflicts between resource users and lack
of post mining opportunities.
· Regulation of mining activities needs to be standardized within the region.
Activities/solutions
·
Policy harmonization - Cooperative harmonization of mining policies, particularly related to shared
resources and cumulative impacts and their mitigation, will be needed.
·
Cumulative impact assessment for BCLME (industry co-funding) - An overall impact assessment of
the mining industry is needed.
·
Enhanced consultation (sectoral & regional) is needed to reduce impacts of mining and ensure
benefits accrue and conflicts are reduced.
·
Cooperative training will be needed for the effective management of mining impacts, as well as
developing activities following cessation of mining.
Priority
·
Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those
activities which address transboundary problems requiring incremental funding are listed.
28
Anticipated outputs
· Environmental management plan An overall environmental management plan for the whole BCLME will be produced, including management
plans for mitigating mining and other impacts.
· Integrated management will be the output of the above plan.
· Solution to capacity problem This will be the result of training to improve assessment and management capacity with respect to the
transboundary isues.
· Regional training packages on managing mining impacts, community development following mine closure
29
TABLE A3. RESPONSIBLE DEVELOPMENT OF MARICULTURE
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-
TRANS-
ACTIVITIES/
PRIORITY
INCRE-
ANTICIPATED
UNCERTAINTIES
ECONOMIC
BOUNDARY
SOLUTIONS
MENTAL
OUTPUTS
CONSEQUENCES
CONSEQUENCES
COST
(5y)
A3. Mariculture is
· Inadequate
· Threat to
· Environmental
· Employment &
· Biological
· Undertake
1
$ 300 000
· Report on
under-developed but
policy
biodiversity
variability
sustainable
invasion to
socioeconomic and
socioeconomic
this is rapidly changing:
· Differential
· Diseases
· Market uncertainty
livelihoods
adjacent country
feasibility
assessment
Mariculture has the
regional
· Conflict over
· Feasibility
· Revenue
by alien species
assessment as
· Feasibility report
potential throughout the
policy -
space/markets
· Potential growth
· Threat to
basis for and
· Harmonised
Benguela region to
policies
· Eutrophication
industry
biodiversity
harmonisation of
policy and
provide labour-intensive
differ in the
· Common
national policy and
regional policy
employment, protein
three
problems, shared
develop regional
· Training
and foreign currency
countries
solutions
policy to mitigate
package
from export of high
· Space
against potential
value products. The
· Lack of
problems and
responsible
information
promote
development of a
responsible
mariculture industry is
development of
hampered by lack of
moriculture in
information and
BCLME
capacity and lack of
harmonised/regional
policy.
Ecosystem effects of
mariculture
developments are
uncertain; for example
introduction of exotic
species and
transboundary
consequences thereof.
A3 EXPLANATORY NOTES. PROBLEM: MARICULTURE REQUIRES RESPONSIBLE DEVELOPMENT
Causes
· Introduction of exotics Mariculture may use exotic species, which can create threats to biodiversity & ecosystem function.
· Inadequate policy While some countries have policies in place, others do not. Policy may not be enacted even where it exists, although at least
Namibia apparently has a good policy that is about to be enacted.
· Differential regional policy Policies differ among the three BCLME countries. It will be necessary to harmonize policies to minimize
transboundary effects of mariculture.
· Space The coastline of the region experiences mostly a high energy wave climate. This means that sheltered water space needed for mariculture
is limited, and other sectors also make use of sheltered water, including ports, fisheries and tourism. This results in conflict with other sectors.
· Lack of information. One of the reasons mariculture is poorly developed in the region is lack of information and lack of capacity. This is
particularly true when it comes to the use of mariculture to develop and broaden the livelihoods of coastal communities.
30
Impacts
· Threat to biodiversity The introduction of exotic species for mariculture purposes may threaten indigenous biodiversity by displacing indigenous
species.
· Diseases Introduction of species for mariculture may spread disease, and cause other unwanted side effects.
· Conflict over space/markets Conflicts among sectors for limited sheltered water space are common. Transboundary conflicts over markets may
occur, and countries without clear policies may be denied certain markets.
· Eutrophication is a consequence of uncontrolled development of feed-based mariculture systems. Such development must occur only within the
confines of strictly enforced guidelines.
Risks/uncertainty
· Environmental variability This creates uncertainty about the suitability of the limited sheltered water space for mariculture.
· Market uncertainty Means that the development of mariculture carries high risk for potential entrepreneurs
· Feasibility The feasibility of mariculture is not known for many potential species.
· Threat to biodiversity, introduction and spread of diseases.
Socioeconomic consequences
· Employment & sustainable livelihoods Mariculture has the potential to allow the broadening of the livelihoods of coastal communities if
developed with a sustainable community development policy
· Revenue Revenue may accrue not only to entrepreneurs but also to local communities and to the national revenue base. However, the latter will
be small due to the limited water space available.
· Potential growth industry Mariculture is one of the few industries based on living resources that has growth potential. There is very limited
capacity for the expansion of harvesting from the wild. Clear sight must be kept of the limited space availability though.
Transboundary consequences
· Mariculture is underdeveloped in all three countries and is being activity promoted throughout the region in view of its economic and employment
potential. Co-operative transboundary activities that promote the responsible development of mariculture will minimise negative enviromental
consequences and also help reduce pressure on traditionally (over) harvested resources.
· Differences in policy among countries in the BCLME could lead to conflicts(e.g. as a result spread of disease from one country to another, alien
species invasion of the ecosystem from a country point source, market conflicts etc), and differential development of the mariculture industry.
Harmonization of policy will reduce the potential harmful effects of differential development.
· The introduction of exotic species into the region for mariculture, by any one country, has the potential to lead to transboundary biological
invasions of the target organism or other species accidentally introduced with it. Such invasions have the potential to be a threat to the biodiversity
of the BCLME as a whole.
31
Activities/solutions
· Socioeconomic assessment of potential A full socioeconomic assessment needs to be conducted into the ability of mariculture to contribute to
regional economy and the improvement in the living conditions of coastal communities.
· Feasibility assessment The feasibility of mariculture for particular species in certain areas of the region needs to be assessed, and the best species
for development need to be chosen on the basis of this assessment.
· Formulate harmonized policy for the region Crucial if the negative effects of one country's policy on the economic potential of another are to be
precluded.
· Training Training will be needed, particularly in terms of promoting community-based mariculture, as well as the overall management of
mariculture in the region.
Priority
·
Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those activities which address transboundary problems
requiring incremental funding are listed.
Anticipated outputs
·
Report on socioeconomic assessment will include advice for action, particularly targeted at communities
·
Feasibility report - will include advice on recommended species and areas for regional initiatives
·
Policy statement - should look at overall and community potential
·
Training package aimed at managers, communities and potential entrepreneurs.
32
TABLE A4. PROTECTION OF VULNERABLE SPECIES AND HABITATS
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-
TRANS-
ACTIVITIES/
PRIORITY
INCRE-
ANTICIPATED
UNCERTAINTI
ECONOMIC
BOUNDARY
SOLUTIONS
MENTAL
OUTPUTS
ES
CONSEQUENCE
CONSEQUENCES
COST (5y)
S
A4. Threats to vulnerable
· Salt
· Threat to
· None given
· Tourism
· Most vulnerable
· Assessment of
1
$ 500 000
· Ecosystem
species: Human impact
production
global
species occur
status of
status
on the ecosystem by way
· Population
biodiversity
throughout the
vulnerable
assessment and
of fishing, increasing
migration to
of coastal
region or migrate
species and
report
pressure on the coastal
coast
birds
between countries.
habitats - both
zone, pollution etc. has
· Pollution
· Ecosystem
National activitiies
those which
impacted negatively on
· Reduction of
change
have
are shared
components of the
prey through
· Loss of
transboundary
between
system, in particular top
fishing
wetlands
consequences.
countries and
predators such as coastal
· Historical
· Population
· Common
those which
birds, e.g. penguins and
harvesting
reduction
Problems, shared
play a key
gannets.
· Competition
· Competition
solutions.
role in whole
for space &
for exploited
ecosystem.
Vulnerability of habitats:
prey (seals,
resources
Several habitats, in
birds, humans)
particular coastal habitats
have been perturbed or
lost as a consequence of
development and other
human impacts, e.g. loss
of wetlands, destruction
of mangroves, lagoons,
etc. These have
transboundary
consequences and may
be significant globally.
A4 EXPLANATORY NOTES. PROBLEM: THREATS TO VULNERABLE SPECIES AND VULNERABILITY OF HABITATS
Causes
· Salt production Changes to wetlands and lagoons
· Population migration to coast especially mangroves. This is a worldwide trend. Logical consequence is a threat to habitats and resources that are
attractive to tourists.
· Pollution Impacts on threatened populations, especially penguins.
· Reduction of prey through fishing Humans catch fish that are the food of seals & seabirds, reducing food available for them, and can lead to
breeding failures in some years as an example.
· Historical harvesting Especially penguins & gannets, particularly eggs and guano. This is one of the reasons these populations are in a depressed
state.
· Competition for space & prey (seals, birds, humans) Seals & seabirds compete with one another for food and breeding space. Both are in
competition for food and space with human populations.
33
Impacts
· Threat to global biodiversity of coastal birds eg. African penguins, bank cormorants. Various sciencific publications by R.J.M Crawford and co-
workers refer - also see BCLME Thematic Reports 1-5 for overviews and references to changes documented in the BCLME.
· Ecosystem change. Various sciencific publications by R.J.M Crawford and co-workers refer - also see BCLME Thematic Reports 1-5 for
overviews and references to changes documented in the BCLME
· Loss of wetlands. Various sciencific publications by R.J.M Crawford and co-workers refer - also see BCLME Thematic Reports 1-5 for
overviews and references to changes documented in the BCLME
· Population reduction This has happened to several resources.
·
Competition for exploited resources Harvesting of pelagic resources has had a huge impact on food availability for other top predators.
Risks/uncertainty
· None were identified.
Transboundary consequences
· Most vulnerable species, including several endemics, occur throughout the region and in some cases internationally. Some vulnerable habitats
occur regionally (e.g. wetlands and lagoons), others in one country (e.g. mangroves), but many are of importance to migratory species. Therefore
the consequences of any actions, whether national, regional or international, will have direct transboundary consequences and may be of
significance globally.
· National policies to enable protection of vulnerable species and habitats need standardization throughout the region.
Socioeconomic consequences
· Tourism Marine mammals, seabirds, turtles & vulnerable habitats (e.g. wetlands) contribute extensively to tourism.
Activities/solutions
· Assessment of status of vulnerable species and habitats Work has started in some countries, but a holistic regional study is sought.
Priority
· Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those transboundary activities whihc address
transboundary problems requiring incremental funding are listed
Anticipated outputs
· Ecosystem report A report on the status of the ecosystem, and the impacts of human activities on the relationships among non-consumptive
resources, together with management advice.
34
TABLE A5. ASSESSMENT OF NON-HARVESTED SPECIES AND THEIR ROLE IN THE ECOSYSTEM.
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-
TRANS-BOUNDARY
ACTIVITIES/
PRIORITY
COST (5y
ANTICIPATED
UNCERTAINTIES
ECONOMIC
CONSEQUENCES
SOLUTIONS
OUTPUTS
CONSEQUENCES
A5. Role of non-
· Lack of
· All impacts
· Unable to predict
· Food security
· Many non-targeted
· Dedicated
1
$ 1 000 000
· Information on
harvested species
information
are unknown
impacts of changes in
potential
species have
joint surveys
non-harvested
in the ecosystem
abundance of
· Jobs
transboundary
and
species,
is unknown.
unharvested species
· Revenue
distributions. Some
assessments
assessment of
Assessments of
upon harvested
have potential for
of non-
ecosystem role.
non-harvested
species
harvesting, but role in
harvested
· Ecosystem model
species (except
· Predator/prey
ecosystem is
transboundar
for management.
for some
relationships
uncertain. Action by
y species to
seabirds and
· Large unknown biomass
one country could
provide
marine
· Market potential
disturb ecosystem in
baseline for
mammals) are
· Economic
absense of info.
integrated
not conducted.
viability
ecosystem
Some of these
· Unknown impact of
· Common problem,
management.
species probably
harvest
Shared solutions
have high
· Ecosystem impact of
biomass (e.g.
pollution
light and lantern
fish), have
potential for
harvesting (and
with it job and
wealth creation),
yet the
consequences of
harvesting on the
food webs and
presently
harvested species
are uncertain.
There is a
general lack of
knowledge on
the subject.
A5 EXPLANATORY NOTES. PROBLEM: UNKNOWN ROLE OF NON-HARVESTED SPECIES IN THE ECOSYSTEM
Transboundary consequences
· Many unused or underused taxa in the BCLME have transboundary distributions, and therefore any exploitation or shared knowledge gained in one country would have an
effect in all countries. Such ecosystem effects ought to be addressed in a dedicated manner by gaining basic knowledge of what is in the system, its biology, and what role it
plays, and how it can be impacted by anthropogenic activity.
Activities/solutions
· Joint dedicated surveys & assessment Such surveys need to be dedicated to the non-harvested species because of the special technology needed.
35
Priority
· Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those activities which address transboundary problems
requiring incremental funding are listed.
Anticipated outputs
· Information on non-harvested species and assessment of their role in the ecosystem.
· Ecosystem model as a tool for sustainable integrated management of the BCLME
36
TABLES B: ASSESSMENT OF ENVIRONMENTAL VARIABILITY, ECOSYSTEM IMPACTS AND IMPROVEMENT OF PREDICTABILITY.
TABLE B1. REDUCING UNCERTAINTY AND IMPROVING PREDICTABILITY.
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-
TRANS-
ACTIVITIES/
PRIORIT
INCRE-
ANTICIPATE
UNCERTAINTIES
ECONOMIC
BOUNDARY
SOLUTIONS
Y
MENTAL
D OUTPUTS
CONSEQUENCES
CONSEQUENCES
COST (5y)
B1. The BCLME is a complex
· Complexity
· Change to coastal
· Long-term net
· Uncertain
Climate Change
· Develop
1
$ 1 600 000
· Regional
and highly variable
of processes
ecosystems from
change or natural
employment (job
· Contribution to
regional
early
system for which there is
· Poor
altered wind
cycles?
losses and gains)
global climate
early
warning
evidence of system
understandin
field/rainfall
· Time periods
· Variation in
change (CO2,
warning
systems for
change and fragmentary
g of
· Changes in coastline
sufficient long to
revenue
methane flux)
system for
major env.
but important evidence of
processes
morphology
detect changes?
· Over- and under-
Ecosystem
env. change
1
$ 400 000
events/chang
increasing
and cause
· Damage to coastal
utilization of
· Shifts in
· Targeted
e.
instability/variability.
and effect
infrastructure
resources.
distribution of
feasibility
Scales of variability
relationships
· Unpredictable
· Lack of food
biota
assessment
· Quantificatio
include: A.. large scale
· Poor
variations in
security
· Loss of species/
of PIRATA
n of utility/
sustained events; B:
understandin
zooplankton and fish
· Human population
biodiversity
linkup/applic
1
$ 250 000
application
decadal changes; and C:
g of global
egg/larval survival
migration
· Altered food webs
ation to
of PIRATA
high frequency short-
driving
· Unpredictable
· High production
· Disruption of
BCLME
for SADC
lived events and/or
forces
changes in fish
costs
faunal migrations
· Targeted
· Information
episodic events. Human
(linkages)
growth, mortality and
· National/regional
Fisheries
transboundar
needed to
impacts on the BCLME
· Lack of data/
recruitment
conflicts
· Unsustainable
y assessment
design
(e.g. by fishing) is
information
· Unpredictable
·
management of
of largescale
2
[$ 300 000]
monitoring/
superimposed on the
Reduced capacity
· Inadequate
changes in species'
shared and
hypoxia/imp
predictive
inherent natural
to support artisanal
mathematical
abundance,
straddling stocks
acts
systems
variability, and the
fisheries
models
composition,
· Altered fish
· Assess role
· Quantificatio
combined effect of
· Changes in
· Lack of
distribution and
spawning patterns
of upwelling
1
$ 100 000
n of CO2 flux
anthropogenic
government
capacity
availability
and population
system as
disturbance and this
revenue, private
· Regime shifts
shifts
CO
2
variability have been
income and
·
·
source/sink
· Record of
implicated in ecosystem
Cross boundary
exports.
Unpredictable
· Analyze
1
$ 250 000
decadal
change and the collapse
movements of fish,
fluctuations and
plankton data
ecosystem
of harvested resources.
seabirds and seals
availability of fish
archives for
changes
There is also
· Change in flux of
stocks
measurement
· Regional
considerable uncertainty
CO2, methane and
· Unpredictable and
of decadal
environment
regarding ecosystem
H2S between
variable
change
al
status and yields. Lack
atmosphere, ocean
distribution of
· Develop
2
[$ 50 000]
analysis/repo
of information about and
and sediments
fishery benefits
transboundar
rting system/
understanding of
· Difficulties in
· Regional
y state of the
2
$ 300 000
network
environmental variability
managing resources
economic
enviroment
· Knowledge
and system-wide impacts
sustainable
instability and
analysis/repo
2
$ 50 000
and expertise
hampers sustainable
· Operational
unemployment
rting system.
on global
management of BCLME
difficulties with
· Regional conflicts
· Develop
2
$ 100 000
climate links
resources and results in
resource utilization
with other users
links with
· Predictions
the non-optimal
· Assessment of
Coastal
CLIVAR
and models
utilization of these
anthropogenic
infrastructure
·
1
$ 400 000
Adapt/develo
·
resources.
impacts difficult
· Costly
Regional
maintenance of
p predictive
advisory
coastal
models
groups
infrastructure
· Establish
1
$ 50 000
· Availability
regional
of important/
37
advisory
useful data
groups
· Regional
· Data
env.
gathering
variability
community
network.
projects
· Links with
· Transbounda
Gulf of
ry env
Guinea LME
variability
networking(i
ncl. internet)
· Establish
links with
the Gulf of
Guinea LME
B1 EXPLANATORY NOTES. PROBLEM: HIGHLY VARIABLE SYSTEM, UNCERTAINTY REGARDING ECOSYSTEM STATUS AND YIELDS
Causes
The Benguela upwelling area is a highly variable "convex" system with three open and variable boundaries. It is unique in that it is bounded at both
equatorial and poleward ends by warm water (tropical) systems viz. Tropical Atlantic and Agulhas Current. It is sensitive to environmental events
(variability and change) in the Atlantic, Indo-Pacific and Southern Ocean. Unlike the Humbolt Current there are few long-term data series to form a baseline
against which changes can be predicted or assessed. There is an uneven spread of data between disciplines and between the participating countries.
Difficulties in predicting changes in the system is a consequence of:
· Complexity of physical, chemical and biological interactions and processes, and the difficulties in predicting environmental variability
· Our limited understanding of cause and effect relationships, compounded by the problems of predicting not only the environmental variability but also
ecosystem impacts
· Our limited understanding of driving forces (global linkages). There is evidence from case studies that inter-annual variability in the northern Benguela is
associated with changes in zonal (east-west) winds in the equatorial Atlantic, and also that there are some common features in the variability of the north
and south Atlantic. There is also fragmentary evidence linking variability in the Pacific El Niño/La Niña (ENSO). Thus, although there are pointers to
the importance of remote physical (global climate) forcing of the Benguela, the linkages and mechanisms are not understood.
· Lack of data/information: Long-term data series are few, and except for the extreme southern Benguela, the ecological processes are poorly understood.
· Inadequate mathematical models applicable to the region: Very little mathematical modeling of the Benguela has been done internationally, and there is a
general lack, in the region, of the capacity (skills and technology) to adapt available models from elsewhere, to run these or to develop new models. This
applies to physical, chemical and biological (ecosystem) modeling. This is a serious drawback to developing predictive capacity.
· Lack of capacity, exacerbated by a south-north gradient in capacity (number of qualified personnel, equipment, vessels etc): The colonial political past in
the region has resulted in insufficient persons with the necessary expertise/skills. Moreover, downsizing and emigration has resulted in further shrinkage
of the skill pool. There is a marked north-south gradient in human and infrastructure capacity in the BCLME, with Angola being the worst off by far, yet
38
with the greatest needs. Thus available capacity is barely sufficient to meet present national needs, and insuffienct to address the priority transboundary
problems.
Impacts
Processes that give rise to variability in the Benguela occur on three temporal and spatial scales (A: large scale sustained events; B: decadal changes; and C: high frequency short-lived events and/or episodic
events). There is evidence that environmental change/variability does impact on the BCLME in a number of ways. However, in order that these changes can be predicted sufficiently well to be useful for
ecosystem management, the cause and effect must be properly quantified. The impact of environmental variability/change includes inter alia the following:
·
Change to coastal ecosystems from altered wind field (strength and direction) and/or rainfall (quantity and distribution)(AB). Changes in wind frequency direction and strength impact on the supply of
nutrients (for productivity), currents and stratification. In addition there is evidence that SST is related to rainfall in the region (although the process mechanisms are not understood).
· Changes in coastline morphology as a result of climatic regime changes and short term events (storms) (BC)
· Short term events (storms) leading to damage to coastal infrastructure (C)
· Variations in zooplankton and fish egg/larval survival and higher level impacts (A, B and C) through changes in primary production and
stratification/turbulence caused by changes in wind frequency, direction and strength.
· Changes in species' abundance, composition, distribution and availability (A, B and C) i.e. ecosystem response to environmental change.
· Changes in fish growth, mortality and recruitment (A, B and C) - these have major implications for resource management.
· Cross boundary movements of fish, seabirds and seals (A, B and C). The majority of harvested species of fish either straddle country EEZ boundaries or
otherwise move across these boundaries from time to time. These movements/shifts are associated with the life histories of the species and also changes
in the environment. The implications if this for sustainable management are obvious.
Regime shifts i.e. increased variability or a net change towards altered state (B). For example switching between species such as anchovy and sardine
(opportunistic) or between sardine and jellyfish (pessimistic!). These regime shifts can occur naturally there is evidence in the sediment record of such
occurrences having taken place historically (prior to fishing). The impact of fish exacerbates the problem. Moreover cyclical changes in wind stress result in
north-south shifts in some straddling fish stocks.
· Change in flux of CO2, methane and H2S between atmosphere, ocean and sediments (B). It is not known with certainty whether the BCLME is a source
or sink of CO2, although it appears to be a net sink. Changes in climate could perturb this balance and feed back to climate. The BCLME could be a
useful "targeted site" for assessing the role of climate change on upwelling systems and feedback to climate from CO2 release/uptake.
Risks/uncertainty
Limited understanding of this highly variable system means that it is uncertain whether the observed variability reflects sustained long-term net change or
natural cycles, and whether the available data series are sufficiently long to enable us to determine this.
Socioeconomic consequences
The quality of advice given to resource managers is reduced by the ability to predict, with confidence, short-, medium- and long-term changes in the
Benguela system. A consequence of this is that responsible resource management must err on what is percieved to be (but which may not be) the
conservative side. This leads to:
· Uncertain employment (job losses and gains)
· Variations in revenue
39
· Sub-optimal utilization of resources (particularly by artisanal fisheries)
· Lack of food security
· Human population movements in response to variable resource availability
· High production costs e.g. in fish processing
· National/regional conflicts
· Changes in government revenue, private income and exports
Transboundary consequences
Sustained major environmental events (e.g. Benguela Niños), decadal change and major short-term perturbations (e.g. 10- or 50-year storm events) do not
respect country EEZ boundaries, but rather impact on the BCLME as a whole. In other words the types of environmental variability/change which are the
focus of the BCLME programme are system-wide and in essence transboundary. Moreover, the BCLME is believed to play a significant role in global ocean
and climate processes besides its importance to Angola, Namibia and South Africa. Many of the transboundary consequences listed below would occur
regardless of the high variability of the system. Nevertheless our ability to manage them effectively is limited by our predictive capability. Some of the
consequences of increased variability or sustained change include:
Ecosystem
· Shifts in distribution of biota - for example decadal scale shifts in sardine and anchovy from Namibia to Angola and back have been documented.
· Loss of species/biodiversity - Alien species have also displaced indigenous species(e.g. spread of Mediterranean(blue) mussel from near Cape Town to
Central Namibia)
· Altered food webs
· Disruption of fish, bird and mammal migrations - cf 1995 Benguela Niño
Fisheries
· Unsustainable management of shared and straddling stocks
· Altered fish spawning patterns and population shifts
· Unpredictable fluctuations and availability of fish stocks e.g. collapse of anchovy stock around 1990
· Unpredictable and variable distribution of fishery benefits e.g. which resulted in the closure of fish canning factories
· Regional economic instability and unemployment
· Regional conflicts over declining resources/stocks
Coastal infrastructure
· Costly maintenance of coastal infrastructure
Climate Change
· Changes in the status and/or functioning of the BCLME may affect its contribution to global climate change through its role as a source/sink of CO2 and
source of methane. Moreover the geographic location of the Benguela at a choke a major route for the transfer of heat between the Indo-Pacific and
Atlantic, means that the BCLME may be an important site for early detection of global change.
Activities/Solutions
40
Without good baseline information and wider regional coordination and articulation, major problems and issues facing the three countries bordering the
BCLME cannot be resolved. It is necessary to undertake targeted assessments of priority environment variability issues/problems and to develop appropriate
systems, linkages and networking.
· Development of a suitable needs-driven, cost-effective regional environmental early warning system for the BCLME by cross linking existing national
systems.
· Transboundary assessment of low oxygen water formation, dynamics and continuity and transboundary impacts.
· Feasibilty assessment of extension of and/or link-up to the PIRATA moored buoy array in the tropical Atlantic to enhance understanding of links
between weather, climate and fish. (PIRATA is an Atlantic equivalent but smaller version of an ocean buoy network in the Pacific, which is used to
forecast EL Niños and La Niñas. The value of linking the BCLME with the PIRATA system would be in the forecasting of Benguela Niños and
anomalous events originating in the tropical Atlantic.). If the feasibility assessment were to prove successful (and it looks like it will), then there is also
an excellent chance of ongoing involvement between the region and PIRATA being funded from country sources and donors.
· Determination of role of upwelling systems as a CO2 source/sink and methane source. The value of this to the international community has previously
been commented on. Moreover it will provide an obvious link between the International Waters and Climate Change components of GEF. A modest
demonstration project would be appropriate.
· Development of community projects for cost effective environmental information gathering and environmental education. Public awareness and
involvement are seen as essential components for the successful implementation of the BCLME Programme both for cost effective information
gathering/monitoring and also to help reduce anthropogenic environmental impacts on the ecosystem.
· Analysis of plankton archives and other (oceanographic) data collections baseline information for measurement of decadal change. These collections
are unique assets and initial indications are that they may hold the key to unraveling some of the decadal variability which has characterized the BCLME
of the last 50 years and which has hampered sustainable harvesting of living resources.
· Develop state of the environment analysis/reporting system for use on a regional basis in the BCLME
· Develop links with CLIVAR and CLIVAR Africa (CLIVAR = Climate Variability and Predictability Project of the World Climate Research Programme)
· Adapt/develop predictive mathematical models applicable to the region the utility of this has been referred to elsewhere.
· Establishment of regional advisory groups and networking centres. This is a low cost activity with potential large benefits.
· Develop transboundary environmental variability networking for region this links in with the proposed early warning system(see above). It will make
extensive use of the internet..
· Establish links with the Gulf of Guinea LME Clearly the BCLME does not function in isolation from the rest of the south Atlantic, so building
bridges/networking with other LME projects could provide valuable spin-offs in both directions.
Priority
·
Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those activities which address transboundary problems
requiring incremental funding are listed.
Anticipated outputs
41
· Proven/validated regional environmental early warning system appropriate for the BCLME in a form which could be used to leverage future country and
donor co-financing for permanent implementation.
· Assessment of utility/application of a PIRATA-type buoy array for the BCLME
· Documented assessment of information needed to design monitoring/predictive systems
· Assessment of decadal ecosystem changes in the BCLME since the 1950s based on historical/archival data and collections
· An established regional environmental analysis/reporting system/network and activity centre
· Assessment using the best available knowledge and expertise links between the BCLME and the global climate system.
· Quantification of CO2 and methane source/sink relationships in the BCLME with an understanding of its applicability to other boundary systems and
climate models
· Useful predictions and models
· Identification of cost-effective early-warning indicators of environmental changes that impact on fish stocks in the BCLME
· Establishment of regional enviroment network and reporting system - making full use of remotely sensed products and the internet, in a form that it can
be self-sustaining operationally.
42
TABLE B2. CAPACITY STRENGTHENING AND TRAINING.
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO
TRANS-
ACTIVITIES/
PRIORITY
INCRE-
ANTICIPATED
UNCERTAINTIES
ECONOMIC
BOUNDARY
SOLUTIONS
MENTAL
OUTPUTS
CONSEQUENCES
CONSEQUENCES
COST (5y)
B2. There is a lack of capacity,
· Limited inter
· Inability to
· Commitment to
· Sub-optimal or
· Uncoordinated
· Assess capacity
1
$25 000
· Capacity
expertise and ability to
country exchange
participate in
supporting
over utilization of
resource
needs to address
development
monitor environmental
(training)
regional decision
capacity
renewable
management,
transboundary
strategy for
variability, to assess the
· Degrading and
making processes
development by
resources due to
research and
issues.
region
linkages and ecosystem
downsizing of
· Regional imbalances
governments of
lack of
monitoring
· Devise strategy *
· Strategy for job
impacts of this variability and
research
in: baseline
the BCLME
information,
programmes
for developing
creation (and
to develop a predictive
institutions
information,
region
knowledge and
· Management of
job opportunities,
N/A to GEF
salaries)
capability required for
· Inadequate
predictive capacity,
· Political and
understanding
overall system by
salaries and
sustainable integrative
training programs
data collection
economic
required for
all three countries
infrastructure
BCLME management. There
· Lack of running
ability etc.
uncertainty
resource
is not
· Develop training
· Improved
is also an unequal distribution
funds
· Inadequate
management
harmonized.
partnerships with
1
$250 000
regional
of availability capacity
· Lack of skills to
information for
· Unequal
Capacity gradient
private sector
management of
(human and infrastructure)
maintain
finding indicators of
opportunities for
(south-north)
· Creation of
resources and
between participatory
equipment.
future change
resource access/
leads to uneven
regional
establishment
countries.
· Lack of
· Lack (low)
management
research
multidisciplinary
of new
equipment and
interaction between
· Absence of full
monitoring effort
working groups
institutional
supplies
institutions
stakeholder
in the system as a
· Devise, develop
networks
· Lack of person
· Information which is
participation
whole with
and implement
power
not comparable/
· Creation of
consequences for
appropriate
·
Low salaries
cannot be integrated
conflict
resource
training courses
·
Lack of concern
across the region
· Poorly informed/
management
· Interchange of
1
$25 000
from the policy
advised
· Difficulties with
personnel
· Shared
makers on the
governments at
resource co-
between
expertise
ecosystem issues.
all levels
operation
countries to gain/
· Brain drain
· Low institutional
· Inability to
transfer expertise
sustainability
monitor or
and knowledge
manage the
· Improve
system as a whole
networking via
1
internet
·
Improve public
2
information/envir
onmental
education (pilot
project)
B2 EXPLANATORY NOTES. PROBLEM: LACK OF CAPACITY, EXPERTISE AND ABILITY TO MONITOR ENVIRONMENTAL VARIABILITY
Causes
The three countries (Angola, Namibia and South Africa) bordering the BCLME are developing countries with requirement to meet the basic living needs of
their peoples. These countries have emerged from after long periods of colonialism and oppression and are attempting to develop their economies and social
structures. Funding for marine monitoring and assessment activities are very limited and policy makers are not always fully aware of the importance of
transboundary environmental variability/change in ocean management applications. Viewed collectively, the lack of capacity can be ascribed to the
following:
43
· Lower priority placed on environmental issues by policy makers
· Limited inter country exchange of personnel for liaison, experience sharing and training
· Degrading and downsizing of research institutions as a result of pressure to reduce the size of the civil service
· Inadequate training/skill development programmes
· Limited funds to meet day to day running expenses, let alone to invest in hardware and capital items.
· Limited skills to maintain equipment.
· Limited availability of equipment and supplies most high tech equipment needs to be sourced abroad, and unfavourable local currency exchange rates
have made this equipment unaffordable.
· Severely limited numbers of trained personnel the lack of trained personnel is a direct consequence of colonialism and also the former apartheid policy
applied in Namibia prior to 1990 and in South Africa prior to 1994. This has resulted in a legacy of a poor skills pool and an unequal distribution of
skills within countries and between countries.
· Inadequate remuneration for government researchers (competition from the private sector).
· Brain drain; loss of personnel to the private sector and overseas because of salaries are not competitive and career prospects uncertain.
Impacts
The consequences of insufficient funding of research in the BCLME include:
· Regional imbalances in baseline information, predictive capacity, data collection ability etc. There is a sharp gradient in the numbers of trained
personnel from south to north.
· Limited ability to participate in regional decision making processes, as too few people are available to do the tasks at hand.
· Inadequate information for identifying indicators of future change
· Limited interaction between institutions. This problem is fast disappearing as a consequence of these countries to collaborate.
· Collection of information which is not comparable/cannot be integrated across the region
Risks/uncertainty
· Although the governments of the region are committed to capacity (skill/expertise development), this commitment is according to perceived national
priorities. There is uncertainty with regard to the priority status of marine science, technology and management at the regional level.
· Political and economic uncertainty results in potential "recruits" choosing more lucrative careers particularly those that favour mobility (emigration).
Socioeconomic consequences
The underestimation by policy makers of the importance of developing and maintaining sufficient research capacity to manage the resources of the BCLME
has resulted in numerous socioeconomic problems including:
· Sub-optimal or over utilization of renewable resources
· Unequal opportunities for resource access/management
44
· Absence of comprehensive stakeholder participation
· Creation of conflicts
· Poorly informed/advised governments at all levels
· Low institutional sustainability
All of the above are in turn direct consequences of inadequate/inappropriate communication and in some case lack of trust between various players.
Transboundary consequences
The Benguela ecosystem is believed to play a significant role in global ocean and climate processes besides its importance to Angola, Namibia and South
Africa. Consequences of poor national and regional management practices thus have wide reaching consequences including:
· Non cost-effective resource management, research and monitoring activities (fragmented, poorly planned and unlikely to achieve the objectives of
ensuring sustainable management).
· Management of overall system by all three countries is not harmonized. Capacity gradient (south-north) leads to uneven research monitoring effort in the
system as a whole with consequences for resource management e.g. possible bias in information and advice leading to inappropriate decision making.
· Difficulties with co-operation in respect of sustainable resource utilization. A holistic approach to correct the damage done in the past from fragmentation
and ad hoc "crisis" management.
· Inability to monitor or manage the ecosystem as a whole The transboundary nature of the issues and problems in the BCLME necessitates a holistic
approach
Activities/solutions
· The first action must be a comprehensive assess of the real needs for human capacity and infrastructural development/maintenance relevant to the
identified transbouondary issues in which clear priorities are listed. This must be executed in co-operation with all stakeholders to ensure a proper
balance and minimum vested interest bias.
· Institutional downsizing, freezing/reduction/non-creation of posts, poor salaries and career prospects are limiting factors. If not addressed, recruitment
and training initiatives will provide little or no long-term benefits. It is thus vital that a comprehensive strategy be developed to address the above (.
(Much of the problem stems from incorrect perceptions and poor communication.). This activity although very important, is inappropriate for GEF
funding, and will be pursued through other avenues.
· Develop training partnerships with private sector. This will promote private sector "buy-in" and provide a point of departure for long-term co-financing
with industry and business.
· Devise, develop and implement appropriate training courses appropriate for the needs of the region. (The focus of courses developed for application in
Western Europe and North America is not always suitable for implementation in developing countries.)
· Creation of regional multidisciplinary working groups. This will be a cost-effective mechanism for consultation, cooperation, skill development, trust
building etc.
· Interchange of personnel between countries to gain/ transfer expertise and knowledge. To be successful this must be tri-directional.
· Improve networking via internet. It is envisioned that increased use of electronic is the key to the success of the BCLME programme at all levels. It will
be particularly beneficial for training and system monitoring.
45
· Improve public information/environmental education (pilot project). There is a relative lack of public awareness about the BCLME, human impacts on
the ecosystem, problems to be addressed to ensure its sustainable utilization and conservation of biodiversity, opportunities for job creation and wealth
generation etc. A pilot project designed to increase awareness at all levels is seen as important.
Priority
·
Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Except for activity asterisked, only those activities which address
transboundary problems requiring incremental funding are listed.
Anticipated outputs
· Capacity development strategy for the region relevant to addressing transboundary concerns as per the Strategic Action Plan.
· Strategy to ensure secure posts for existing and newly trained personnel (including market related remuneration)
· New institutional networks taking advantage of the internet and world wide web
· Improved regional management of resources
· Increased multilevel public awareness of the issues and problems and the need for sustainable integrated management of the BCLME.
· Improved infrastructure and improved availability of persons with the necessary skills.
46
TABLE B3. MANAGEMENT OF CONSEQUENCES OF HARMFUL ALGAL BLOOMS.
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-
TRANS-
ACTIVITIES/
PRIORITY
INCRE-
OUTPUTS
UNCERTAINTIES
ECONOMIC
BOUNDARY
SOLUTIONS
MENTAL
CONSEQUENCES
CONSEQUENCES
COST (5y)
Harmful algal blooms are a
· Natural processes · Poisoning and
· Increase or
· Human mortality
· Occurrence of
· Develop an HAB
2
$50 000
· HAB regional
conspicuous feature of upwelling
· Introduction of
mortality of human
decrease in
· Loss of tourism
harmful algal
reporting system
network
systems. The frequency of
cysts in surface
consumers of marine
incidence and
revenue
blooms in all
for BCLME
occurrence, spatial extent and
waters
organisms
intensity of
· Increased cost of
three countries
region as a whole
duration of harmful algal blooms
· Nutrient loading
· Mortality (mass) of
HABs
shellfish
· Migrations of
· Regional HAB
· Regional
appear to be increasing in the
of coastal waters
marine organisms
· Role of HABs in
production
species across
contingency
2
$100 000
contingency
BCLME. The harmful effect of
from
· Disruption of
the system as a
(monitoring,
national
plans
plan
these blooms is manifested in two
anthropogenic
mariculture activities
whole
testing,
boundaries
· Community
2
$50 000
main ways: production of toxins
activities
· Interference with
· Contribution of
depuration)
(See Notes)
projects linked to
· Public
which cause mortalities of
· Changing state of
recreational use of
anthropogenic
· Loss of fish/
ministries of
education
shellfish, fish and human; and
the Benguela
the sea
nutrient loading
shellfish/maricult
health
2
[$50 000]
materials
anoxia in inshore waters which
ecosystem
· Anoxia which in
to incidence of
ure markets and
· Mitigation of
also can lead to massive mortalities
· Introduction of
turn may cause
HABs
jobs
impacts of HABs
of marine organisms.
exotic species
massive mortalities
· Improve national
2
(National)
· Proactive
of marine organisms
capacity to
management
monitor
toxins/species
B2 EXPLANATORY NOTES. PROBLEM: HARMFUL ALGAL BLOOMS (HABS)
Causes
· Natural processes HABs occur naturally in the BCLME. Human impact can cause these HABs to spread, and introduce exotic HAB species into the
BCLME.
· Introduction of cysts into surface waters Human activities such as drilling, mining (dredging) and certain types of fishing disturb the sediments and
release cysts of HAB species into the water column, thereby triggering new blooms, and expanding the area impacted by HABs.
· Nutrient loading of coastal waters from anthropogenic activities Increased nutrient loading of coastal waters from e.g. sewage discharges and industries
increase the probability of occurrence of HAB outbreaks.
· Perceived increase in frequency of HABs may be the result of changes in the state of the Benguela ecosystem. (System-wide monitoring for HABs
would be required to discern any definite trend.) Nevertheless the changes in SST and wind stress observed in the BCLME this century would be
compatible with an increase in HAB frequency and distribution.
· Introduction of exotic species (through ballast water, bilge water, mariculture operations etc.) There is little or no control over the discharge of ballast
water from ships entering national waters in the three countries, and there is a suspicion that these discharges may be responsible for the spread of HABs
in the BCLME.
Impacts
HABs affect a wide spectrum of activities in the marine environment. The impacts include:
47
· Poisoning and mortality of human consumers of marine organisms. There is documented evidence of human mortalities in the BCLME as well as non-
fatal impacts.
· Mortality (mass) of marine organisms. The species at highest risk are the filter feeders (e.g. mussels) and organisms that consume these filter feeders.
Mortality can be caused directly by toxins and clogging of gills, and indirectly by depletion of oxygen in the water column.
· Disruption of mariculture activities Mariculture is dependent on good water quality. HABs result in disruption or closure of mariculture facilities
necessitating expensive water treatment, isolation of facilities, etc. Depending on the nature of the mariculture venture and the HAB, the
closure/disruption can be short-lived or permanent.
· Interference with recreational use of the sea Apart from being toxic and unsightly, some HABs cause respiratory problems in swimmers and those
living in close proximity to the sea.
· Anoxia which in turn may cause massive mortalities of marine organisms. For example, in a single episode in St Helena Bay, a biomass of rock lobster
equivalent to or greater than the annual total allowable catch in the entire southern Benguela was lost as a result of a single HAB outbreak.
Uncertainties
· Increase or decrease in incidence and intensity of HABs as a consequence of insufficient monitoring.
· Role of HABs in the system as a whole
· Contribution of anthropogenic nutrient loading to incidence of HABs
Socioeconomic consequences
· Human mortality. Deaths have occurred and numerous people have suffered respiratory difficulties and gastro-intestinal problems as a consequence.
· Loss of tourism revenue (see impacts)
· Increased cost of shellfish production (monitoring, testing, depuration)
· Loss of fish/shellfish/mariculture markets and jobs. Mariculture is a potentially valuable growth industry in the BCLME. It is constrained by a general
lack of information and knowledge, including lack of information about the extent of the HAB problem in the BCLME.
Transboundary consequences
· Incidence and effects of HABs are common to all three countries
· HAB outbreaks can be extensive and straddle national boundaries. In addition advective processes together with shipping operations, and bottom
trawling, and mining(dredging) can redistribute cysts across national boundaries.
Activities/solutions
· Develop an HAB reporting system for BCLME region as a whole. This is seen as a high priority within the BCLME. It is also essential for the
development of a sustainable mariculture industry.
· Community awareness projects linked to national ministries of health to alert the public to dangers associated with HABs
· Develop national/regional HAB contingency plans which include early warning systems and guidelines for medical practitioners to deal with HAB
associated problems
48
· Improve national capacity to analyze for toxins and identify harmful species by sharing expertise between countries
· Mitigation of impacts of HABs on mariculture operations (e.g. relocation of mussels rafts, treat blooms with "herbicides")
Priority
· Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Except for activities asterisked, only those activities which address
transboundary problems requiring incremental funding are listed.
Anticipated outputs
· Established HAB regional reporting network, with transboundary early warning system(to alert neighbouring state when required)
· Regional contingency plan for dealing with effects of HABs implemented in all three countries
· Public education materials prepared and distributed regionally
· Substantial contribution to the sustainable and responsible development of mariculture within the BCLME.
· Proactive integrated management in general.
49
TABLES C: MAINTENANCE OF ECOSYSTEM HEALTH AND MANAGEMENT OF POLLUTION
TABLE C1-3. IMPROVEMENT OF WATER QUALITY; PREVENTION AND MANAGEMENT OF OIL SPILLS; REDUCTION
OF MARINE LITTER
PROBLEMS
CAUSES
IMPACT
RISKS/UNCERTA
SOCIO-
TRANS-
ACTIVITIES/SOL
PRIORITY
INCRE-
ANTIC
INTIES
ECONOMIC
BOUNDARY
UTIONS
MENTAL
OUTP
CONSEQUENCES
CONSEQUENCES
COST (5y)
C1. Deterioration in coastal water
· Unplanned
· Public health
· Few or no
· Loss of tourism
· Transboundary
· Develop standard
1
$100 000
· Shar
quality: Coastal developments
coastal
· Reduced yields
baseline data
· Higher health
pollutant
environmental
solu
and rapid expansion of coastal
development
· Unsafe edible
· Performance
costs
transport
quality
wate
cities, much of which was
· Chronic oil
organisms
standards and
· Altered yields
· Migration of
indicators/criteria
man
unforeseen or unplanned, has
pollution
· Changes in species
thresholds
· Reduced resource
marine
· Establish regional
1
$50 000
· Reg
created pollution "hotspots".
· Industrial
dominance
· National
quality
organisms, e.g.
working groups
prot
Aging water treatment
pollution
· Ecosystem health
commitment to
· Aesthetic impacts
seals
· Training in
2
$100 000
agre
infrastructure and inadequate
· Sewage pollution
and resilience
capacity-building
· Lowered quality
· Negative impacts
marine pollution
· Imp
policy/monitoring/
· Air pollution
· Loss of jobs at
· Cause-effect
of life
on straddling
control
pollu
enforcement aggravates the
· Mariculture
regional level
relationships
· Loss of
stocks
· Plan/adapt
1
$50 000
cont
problem.
· Lack of policy on
employment
· "Hotspots"
regional pollution
· Soci
waste & oil
common
monitoring
upli
recycling
solutions
framework
·
1
(National)
Growth in coastal
· Establish
informal
effective
settlements
enforcement
agencies *
· Demo projects on
2
$500 000
pollution control
and prevention
· Joint surveillance
2
$200 000
C2. Major oil spills: A substantial
· Sea worthiness of
· Coastline
· Recovery period
· Opportunity costs
· Resource sharing
· Regional
1
$50 000
Region
volume of oil is transported
vessels/
degradation
· Cost recovery
(e.g. tourism,
for containment,
contingency plan
conting
through the BCLME region
equipment
· Mortality of coastal
mechanisms
fisheries, salt
surveillance,
development
shared
and within it, and this is a
· Military conflict
fauna and flora
· Return to peace
production)
rehabilitation, etc.
· Research/
rehabil
significant risk of
· Sabotage
in Angola
· Altered yields
· Ramsar site
modeling of
3
plans, r
contamination of large areas
· Human error
· Reduced resource
protection (border
recovery periods
protoco
of fragile coastal environments
quality
wetlands)
· Public awareness
agreem
from major accidents, damage
· Aesthetic impacts
· Transboundary
of notification
3
to straddling stocks and
pollutant
procedures
coastal infrastructure.
transport
· Port state control
3
C3. Marine litter: There is a
· Growth of coastal
· Faunal mortality
· Accumulation
· Loss of fishing
· Transboundary
· Litter recycling
2
· Clea
serious growing problem
settlements
· Negative aesthetic
zones
income
transport
· Harmonization of
3
beac
throughout the BCLME.
· Poor waste
impacts
· Illegal hazardous
· Public health
packaging
· Edu
50
management
· Damage to fishing
waste disposal
· Cleanup costs
legislation
mate
· Little public
equipment
· Loss of tourism
· Public awareness
docu
awareness and
· Job creation in
· Port reception
1
avai
few incentives
informal sector
facilities
1
regio
· Illegal disposal
· Regulatory
· Stan
from vessels
enforcement
2
$50 000
polic
· Poverty of coastal
· Standardized
legis
communities
policies
2
$100 000
pack
· Ghost fishing
· Seafarer
recy
· Fishing discards
education
1
$50 000
ince
C1 EXPLANATORY NOTES. PROBLEM: DETERIORATION IN WATER QUALITY
Causes
· Activities are mainly focused around urban centers, increasing urbanization and associated knock-on effects. Worst effected areas
are Luanda, Walvis Bay and Cape Town.
· Various sectors contributing to pollution, with varied degrees of cross sector co-operative management
· Knock-on effect of introduced mariculture species and associated water quality pollution effects in protected embayments
· Variable consistency in application of policy, both nationally and regionally
· Informal and formal settlements vary in their control of pollution discharges. Pollution is increasing due to urbanization.
· Shipping activities and hydrocarbon exploration and production are major sources of chronic oil pollution.
Impact
· Avariety of factors are responsible for deterioration of human health and ecosystem health/resiliance (Refer to BCLME Thematic
Reports 1-6)
· Species invasion (poorly planned mariculture enterprises), changes in species dominance, reduced yields from ecosystem.
· Loss of jobs at regional level, reduction of regional tourism potential
Risks/uncertainty
· Limited data available from which to evaluate existing water quality, so it is difficult to establish a regional baseline.
· Validity of existing standards and thresholds within the regional context is uncertain.
· Tracing of impacts back to initial causes is difficult and causation is often unknown.
· Reduction of pollution in worst affected areas may not be practicable on short/medium term.
51
Socioeconomic consequences
· Input of nutrients and associated pollution may cause a short-term increase in production, combined with longer-term stock failure.
· These consequences are interrelated: pollution decreases tourism, which reduces jobs, which increases poverty, which in turn
increases pollution.
Transboundary consequences
· Deterioration of water quality may cause species migration (temporary/permanent). Pollutants from industries/activities near to
country borders can be transported across boundaries by prevailing currents.
· Impacts are (variably) common to each of the participating countries a "generic" project with flexibility to meet nations' needs
should be established. Establishment of common policy is necessary to minimise transboundary impacts.
· Most water quality issues are common to at least two of the countries and require common strategy and collective action to
address.
Activities/solutions
· An overall regional working group should be established to effectively co-ordinate integrated solutions to:
Environmental quality indicators
Marine pollution control and surveillance
Regional monitoring/inspection of coastal zone
Regional enforcement of standards
Prevention of "polluters" slipping over the boarder.
Priority
· Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Except where asterisked, only those activities which address
transboundary problems requiring incremental funding are listed.
Anticipated outputs
· Integrated local, national, or regional system implementation with decrease in pollution and associated long-term savings in clean-up and education costs. It
is anticipated that the benefits which will be demonstrated by the proposed actions will be such that leverage of national or donor funding for continued
implementation following the conclusion of the BCLME will be possible in view of the benefits which will acrue from a modest investment.
52
C2 EXPLANATORY NOTES. PROBLEM: MAJOR OIL SPILLS
Causes
· Variability of seaworthiness of vessels operational from the region, as well as transport through the region.
Impacts
· General coastal degradation (temporary habitat loss), with varied recovery rate, depending on species vulnerability and spill
intensity. (Associated monitoring of fauna/flora recovery is essential.)
Risks/Uncertainty
· Recovery period in system is sensitivity-dependent
· Regional and national peace and political stability are most conducive to programme success.
· General environmental deterioration leads to aesthetic deterioration and then tourism loss.
Socioeconomic impacts
· Revenue loss is a function of spill intensity and environmental sensitivity, and duration of spill.
Transboundary consequences
· Regional co-operation needed in use of equipment/manpower.
· Riparian/estuarine boundaries are particularly vulnerable.
· Co-operative management of spills moving across borders. (Management/clean-up of a major spill near country boundary can
only be effective if comensurate actions are taken by the neighbouring state)
Activities/solutions
· Regional co-operation paramount in standards development: policy, equipment, and techniques.
Priority
· Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those activities which address transboundary problems requiring
incremental funding are listed.
Anticipated outputs
· Regional policy and optimal utilization of resources.
53
C2 EXPLANATORY NOTES. PROBLEM: MARINE LITTER
Causes
· Rapid urbanization and unplanned settlement, with variable and limited/no control by authorities.
· Existing formal infrastructure unable to cope with expanding formal developments.
· Public apathy/indifference and difference in behavior across cultural groups.
· "Lost" fishing equipment and associated "wastes."
· Non-returnable/disposabale nature of containers of packaging used in the region. (Absense of regulations and incentatives for
return of containers and use of biodegradable materials)
Impacts
· Aesthetic and multiple impacts are associated with economic loss, although there may be job creation in the informal sector (waste
management).
· Plastics and ropes (including fishing lines) present a significance amd growing hazard to marine mammals and seabirds
(entanglement, ingestion)
Risks/uncertainty
· Volume of hazardous substances dumping unknown.
· Need to identify areas of waste accumulation through natural processes.
· Positive impacts (job creation in informal sector) are balanced by lack of incentives not to litter.
· Potential degree of transboundary movement.
· Issues common to all three countries create a "blueprint" and apply flexibly to all countries.
Activities/solutions
· Public awareness is key to successful implementation and a sustained clean environment primary focus is seafarers
· Common policy/practice and implementation i.e. "return" (bottles) product incentives common policy re boundary transfer and
legislation (packaging) review.
Priority
54
· Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those activities which address transboundary problems requiring
incremental funding are listed.
Anticipated outputs
· Clean coastal zone
· Educated and up lifted public
· Improved legislation and standards implementated from local/national/ regional levels ~ coordinated
· Reduction in negative impacts on marine mammals and seabirds(particularly relevant to threatened/endagered species)
55
TABLE C4. RETARDATION/REVERSAL OF HABITAT DESTRUCTION/ALTERATION.
PROBLEMS
CAUSES
IMPACT
RISKS/UNCERT
SOCIO-
TRANS-
ACTIVITIES/SOL
PRIORIT
INCRE-
ANTICIPATED
AINTIES
ECONOMIC
BOUNDARY
UTIONS
Y
MENTAL
OUTPUTS
CONSEQUENCE
CONSEQUENCE
COST (5y)
S
S
C4. Habitat alteration/
· Diamond mining · Increased turbidity
· Near-complete
· Costly
· Sediment
· Document fully
1
$ 50 000
· Comprehensiv
destruction (see also A4).
· Demersal
(sediment plumes,
lack of data
infrastructure,
transport
presented status
e status report
Several habitats have been
trawling
etc)
· No framework
rehabilitation &
· Common
· Adapt & apply
altered or lost as a
· Variable river
· Benthic community
for impact
maintenance
problems, e.g.
regional marine
1
$150 000
· Regional early
consequence of development
sediment input
destruction
monitoring
· Loss in
erosion
and coastal early
warning
and other human impacts.
and changing
· Mobilization of
· Cumulative
mariculture
· Redistribution of
warning system
system ad
Impacts can be categorized
land use
heavy metals
local vessel
production
marine fauna as
and action plan
action plan
into three areas, viz.:
· Oil/gas
· Faunal impacts e.g.
impacts
· Decreasing
a consequences
· Assess causality
exploration/
reproductive failure
· Climate change
human health
of habitat
of habitat
2
$100 000
· Transboundar
1. Coastal progradation/
production and
· Increased
· Distinguishing
via heavy metal
alteration e.g.
alteration.
y causality
redistribution;
spills
frequency of HABs
impacts from
contamination
hakes, seals
· Adapt & apply
established
2. Nearshore (< 30m)
· Mariculture
· Coastal erosion
natural spatial
· Loss of fisheries
standard
1
$50 000
3. Shelf/slope (200 m)
· Natural
· Organic
and temporal
productivity/
environmental
sediment
loading/anoxic
variation
revenue, e.g.
quality criteria
transport
conditions
rock lobster
· Adapt & apply
(altered erosion)
· Opportunity
regional
1
$100 000
· Built coastal
costs
structure to
· Regional
structures
address
structures and
·
Human
problems
agreements
1/2
[$50 000]
settlement and
· Adapt & apply
resource use
expertise in
· Improved
· Mangroves/coast
coastal
coastal
al deforestation
processes
planning
· Coastal vehicle
tracks
Risks/uncertainty
·
Incomplete/lack of data ~ severely limiting ~ but increasingly available due to mining companies' existing programmes.
·
Should standardize framework for evaluation of impacts.
·
Impacts from multiple vessels in close proximity unknown ~ carrying capacity to be determined.
·
Necessary to distinguish anthropogenic impacts from natural variability.
·
Altered sediment structure and particle size composition with consequence for benthos and remobilization of certian minerals(metals).
Socioeconomic consequences
·
Unknown costs of rehabilitation and subsequent evaluation of rehabilitation success.
·
Human health affected through knock on effect in food chains.
·
Loss of revenue from renewable resources.
Transboundary consequences
·
Marine fauna migrating due to habitat loss.
·
Sediment remobilization.
Activities/solutions
·
The present status requires proper documentation, and establishment of baseline at regional level.
·
Establish/identify regional parameters for approach to early warning systems and associated quality performance standards.
·
Develop mechanisms of co-operation between industries, ministries and other stakeholders, and strengthen capacity
·
Needs-assessment to improve coastal management expertise.
Priority
·
Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only those activities which address transboundary problems requiring incremental
funding are listed.
57
TABLE C5. CONSERVATION OF BIODIVERSITY.
PROBLEMS
CAUSES
IMPACT
RISKS/
SOCIO-
TRANS-
ACTIVITIES/
PRIORITY
INCRE-
ANTICIPATED OUTPUTS
UNCERTAINTIES
ECONOMIC
BOUNDARY
SOLUTIONS
MENTAL
CONSEQUENCE
CONSEQUENCES
COST (5y
S
C5.Loss of biotic integrity:
· Introduction
· Local
· Source of alien
· Loss in
· Transfer of alien
· Harmonize
1
$50 000
· Harmonized regional policy
This refers to
of alien
extincti
commensals?
community
species via
regional
· Co-Financing
ecosystem impacts
species
on
· Invasive ability?
income from
shipping/
policies
2
including changes in
· Selective
especia
· Beneficial or
fishing and
mariculture
· Link with GEF
community
fishing
lly of
harmful?
mariculture
· Natural processes
ballast water
· Regional protocols
composition, species
mortality
benthic
· No baseline data
· Potential public
· Fisher migration
project
1
$30 000
diversity, and
(targeted
species
health impacts
· Shared stocks
· Regional
· Establishment of negotiated marine
introduction of alien
fishing)
· Introdu
· Opportunity
fishing policies
protected areas
species a set of
· Incident
ction of
costs, e.g.
co-management
· Biodiversity conservation baseline
measures of ecosystem
mortality
pathoge
tourism
· Identification of
1
$150 000
· Reduction/ control of alien introductions,
health.
bycatch/
ns
· Political
MPAs (incl.
policy decisions, forum established
discharges
· Genetic
pressure to
Transboundary
· Pollution
impove
over-harvest
areas)
impact
rishme
· Lost income
· Identify genetic
2
$20 000
· Over-
nt (loss
prolonged
populations
harvesting
of
recovery time
structures
· Habitat
resilien
· Uncertainty of
· Develop forum
1
$50 000
alteration
ce)
sustainable
for stakeholder
(e.g.
livelihoods
participation
destruction
· Modification of
and negotiation
of mangrove
food source of
of biodiversity
areas)
consumers
code of conduct
· Lack of
implementati
on of
international
laws
C5 EXPLANATORY NOTES. PROBLEM: LOSS OF BIOTIC INTEGRITY
Causes
·
Introduction of alien species
·
Changes in community composition, population distribution and abundance due to overfishing, selective fishing (targeted at a particular species), and incidental (bycatch)
mortality.
·
Other identified causes included pollution impacts, habitat alteration (including mangrove destruction), and lack of implementation of international conventions (e.g.
Convention on Biological Diversity and marine treaties).
58
·
Lack of holistic approach to ecosystem management i.e. only management of individual species/components in isolation.
Impacts
·
Introduction of pathogens and other commensal species: Alien species (intentionally or inadvertently imported) may arrive with unseen viruses, ectoparasites, and other
commensals.
·
Genetic impoverishment refers to the loss of genetic variability as a result of population `bottlenecks' (severe crash in population numbers) which will normally reduce
population resilience and fitness (ability to cope with future environmental change).
Risks/uncertainty
·
Invasive ability: the ability of introduced species to survive, reproduce and replace indigenous species.
·
Beneficial or harmful? The "beneficial" assessment is perceived as a socioeconomic one (e.g. mussels are tasty and easier to grow in mariculture than indigenous ones), but
the "harmful" assessment is primarily an ecological one. (On the longer term, what may at present be perceived as beneficial may not be sustainable. This has serious
implications for sustainable integrated management of the ecosystem.
Socioeconomic consequences
Alien species:
·
Potential public health impacts refer primarily to pathogens imported with ballast water aliens.
·
Opportunity costs: for example, alien infestations can cause a loss of diving tourism revenue.
Fishing impacts:
·
Political pressure to over-harvest: In a population recovery period, low quotas often cannot be implemented due to political pressure (leading to a very much longer recovery
period).
·
Loss of income: Prolonged recovery periods strain the industry through loss of revenue. Uncertainty of sustainable livelihoods: Government policy incentives are needed to
encourage alternative job creation to sustain fishers during low yield periods, or a temporary industry shutdown.
·
Modification of food source of consumers: in Namibia especially, some cultures will not willingly eat marine fish (although inland fish are eaten). It is a policy attempt to
improve national food security, given that maize is imported and 80-90% of marine fish is exported. Not an option in present-day Angola.
·
Migration of fishers -- when over-harvesting causes depletion of fish stocks, fishers may be forced to move.
Activities and solutions
·
Cognisance is taken of the existing GEF international ballast water management project, in which Saldahna Bay is to be used as a model for a port management plan (cf
SADC application).
·
**NB: Angola is very concerned about uncontrolled dumping / flushing from ships generally (including bilge waters not just marine litter and ballast water).
·
Regional (BCLME region) policy on aquaculture / mariculture should be developed and then harmonized with those of neighbouring countries, including SADC region.
(Refer to B-3)
·
Regional (& national) management plan for biodiversity conservation must include a framework for assessment and prediction of environmental change impacts.
·
Identification of marine protected areas: As the national borders within the BCLME region include two estuaries: a Ramsar site (Orange River mouth) and a proposed Ramsar
site (Cunene River mouth), attention can also be given to possible transboundary marine protected areas.
·
Identify genetic structure of populations: an essential component of a regional biodiversity conservation management plan. It has important implications for fisheries
management (do countries manage the same or different stocks of individual species?). BENEFIT focuses on genetic structure of shared fish stocks in the region, but
BCLME must focus on genetic diversity implications of marine resource management: genetic pollution, loss of heterozygosity, etc.
59
Activities/solutions
·
Harmonisation of national policies and the development of a regional policy.
·
Establish/identify regional parameters for approach to early warning systems and associated quality performance standards.
·
Develop mechanisms of co-operation between industries, ministries and other stakeholders, and add capacity
·
Needs-assessment to improve coastal management expertise.
Priority
·
Proposed activities are ranked on a scale of 1-3 in terms of their perceived priority. Only activities which address transboundary problems requiring incremental funding are
listed.
Anticipated outputs
· Regional quality indicators: Adapt and apply existing environmental quality indicators to the BCLME for specified variables.
· Policy decisions on allocation of seabed: There is a need for a policy decision on whether to renegotiate existing concessions, hold back the granting of new concessions.
"Windows of opportunity" exist between the granting of exploration and production licenses, during which marine protected areas can probably be established. (However, this
would lead to MPAs being restricted to areas rejected by industry, not the proactive establishment of biodiversity-rich MPAs).
· Harmonised regional policy and emergence of regional protocols
· The establishment of a forum for stakeholder participation in negotiating a biodiversity code of conduct is seen as an important outcome.
60
Anchor Environmental Consultants
SYNTHESIS AND ASSESMENT OF INFORMATION ON THE BCLME
THEMATIC REPORT 3
INTEGRATED OVERVIEW OF DIAMOND MINING IN
THE BENGUELA CURRENT REGION
B.M. Clark, W.F. Meyer, C. Ewart-Smith, A. Pulfrich and J. Hughes
AEC Report # 1016/1
March 1999
Anchor Environmental Consultantscc
Department of Zoology
University of Cape Town
Rondebosch 7701
South Africa
Cell: 083 309 1231
Tel/Fax: +27 (21) 685 3400
Email: bclark@botzoo.uct.ac.za
Overview of Diamond Mining in the BCLME
4
Anchor Environmental Consultants
CONDITIONS OF USE
1.
This report is the property of the UNDP who may publish it provided that:
Anchor Environmental Consultants (AEC) is acknowledged in the publication.
AEC is indemnified against any claims from damage that may result from
publication.
AEC receives copies of any publications emanating from this work.
2.
AEC will not publish this report without the prior written consent of the client. AEC
may, however, use technical information obtained from the compilation of this report,
but AEC will not identify either the client, or the subject of this study.
Overview of Diamond Mining in the BCLME
i
Anchor Environmental Consultants
SCOPE
Barry Clark of Anchor Environmental Consultants (AEC) was commissioned by United
Nations Development Programme (UNDP) to prepare an integrated overview of marine
diamond mining in the Benguela Current region (Angola, Namibia and South Africa). The
report was to include the following written terms of reference, received by AEC on September
28, 1998.
A Historical Perspective
Areas of Activities (inter-tidal, shallow-water, offshore)
Key Players and Stakeholders
Diamond Mining Techniques
Operational Practices
Economic and Social Importance
Environmental Policy and Legislation
Environmental Impacts of Activities on Fisheries and Ecosystem
EIA procedures and Mitigation Measures
Environmental Management Plans
Conflict Issues and Resolution Mechanisms
The report was also to document:
Key problems, threats and issues to the environment/ecosystem from marine
diamond mining
Gaps in knowledge (environmental management, monitoring, mitigation)
Transboundary issues
Due to the confidential nature of much of the literature used, references are not specified in
the text but are appended in a bibliography.
The study was undertaken by B.M. Clark, W.F. Meyer, C. Ewart-Smith, A. Pulfrich and J.
Hughes. Sue Lane (Sue Lane & Associates), Dr Gabi Schneider (Ministry of Mines and
Energy, Namibia), Alison Dehrmann (Department of Mineral and Energy, South Africa) and
Dr Mick O'Toole (Ministry of Fisheries and Marine Resources, Namibia) commented on
earlier drafts of the manuscript.
Overview of Diamond Mining in the BCLME
ii
Anchor Environmental Consultants
EXECUTIVE SUMMARY
Historical Perspective
1900's: Early diamond discoveries on the southern Namibian coast result in the start of
terrestrial mining operations
1920's: First diamonds are discovered on the South African coast, leading to a southward
spread in mining operations
1960's: The first diamonds are recovered from the sea, initiating both small scale diver
assisted mining in the nearshore zone and large scale dredging operations in the offshore
zone off the coasts of South Africa and Namibia
1970's: International diamond market slumps resulting in a temporary cessation in
offshore dredging operations, but onshore and small-scale diver assisted mining continues
in the nearshore zone
1990's: As richer onshore deposits become exhausted, offshore mining operations
recommence, initiating an increasing shift in emphasis from onshore to offshore
operations
Major Players and Areas of Operation
Currently, marine diamond mining operations are conducted only in South Africa and
Namibia, largely controlled by a few large companies
Major players in South Africa include De Beers and its affiliates, Alexkor and Trans Hex,
with concession areas covering most of the west coast from Paternoster in the south
(32°45'S) to the Orange River in the north, extending from 100 km inland out to 500 m
depth offshore
Major players in Namibia include Namdeb, Ocean Diamond Mining, Diamond Fields
International and Arena Mining with concessions areas extending from 100 km inland to 3
km offshore, from the Orange River to 26°30'S
Some prospecting has been undertaken off the Angolan coastline and several companies
are negotiating the lease of potential mining areas, but no concessions have yet been
allocated
Overview of Diamond Mining in the BCLME
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Anchor Environmental Consultants
Mining Techniques and Operational Practices
Onshore Mining
Onshore mining is undertaken via large-scale open cast mines, using heavy-duty earth
moving equipment
Overburden is first stripped off to expose underlying diamondiferous gravel, which is then
collected and transported to centralised processing plants
Sometimes sea walls are used to extend terrestrial operations several hundred meters
offshore of the original coastline
Oversize tailings are generally deposited on mine dumps, while undersize material is
pumped into slimes dams or directly into the sea
Nearshore Mining
Diver assisted suction equipment is deployed from the shore or small boats to collect
gravel from littoral and sublittoral areas down to a depth of ~30 m
"Blowers" are sometimes used to give divers easier access to the underlying orebody
Diamondiferous concentrate is bagged and processed ashore while oversize and fine
tailings are deposited overboard
Nearshore mining is opportunistic and weather dependent, with divers generally operating
fewer than 10 days per month
Offshore Mining
Remote operated dredges or drills with airlift systems, deployed from large (50-140 m)
self contained vessels, are used to collect gravel at depths of up 120 m
Gravels are processed into a concentrate onboard which is sent ashore for hand sorting
All tailings generated during the sorting process are discharged to sea
Semi-mobile jack-up rigs and bulk dredges may be introduced in the future to mine lower
grade ores
Environmental Policy and Legislation
Mining and associated activities in South Africa and Namibia are regulated by a suite of
legislative Acts designed to mitigate their effects on the environment, including
requirements for Environmental Assessments (EA's) and Environmental Management
Programmes (EMPs)
Additional legislation also controls pollution at sea, the use of landing facilities, access to
the coastal zone, and damage to natural or cultural resources in these two countries
No information was available regarding Angolan legislation at the time of writing
Overview of Diamond Mining in the BCLME
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Anchor Environmental Consultants
Environmental Issues, Impacts and Mitigation
Marine diamond mining is the cause of a number of socio-economic and biophysical
impacts in South Africa and Namibia, both positive and negative
Major socio-economic benefits provided by the diamond industry include the creation of
employment and tax revenue
Negative aspects include problems associated with the influx of people into small towns,
lack of facilities for waste disposal, gaps created by the shifting emphasis from on- to off-
shore mining, conflict with other resource users and the foreclosure of future land use
options through aesthetic impacts
Little has been done to mitigate problems associated with negative socio-economic
impacts, but attention is being given toward developing alternative land-use options (e.g.
tourism and mariculture), alternative skills training and conflict resolution mechanisms
The de-facto reserve status of the terrestrial diamond areas arising from restricted access
represents the only major positive biophysical impact of diamond mining in the BCLME
In terms of the overall aerial extent, mining affects less than 1% of the concession areas in
South Africa and Namibia per annum and negative impact are largely deemed to be of low
significance
Several negative impacts have been identified on a local scale, including impacts on
vegetation and soils, generation of sediment plumes, disruption of littoral and sublittoral
benthic communities, kelp cutting, conflict with the fishing industry and disturbance of
marine mammals and birds
Mitigation measures have been introduced to address most of these impacts
Most of the larger diamond mining companies and many of the smaller operators already
have, or are in the process of drawing up Environmental Management Plans
Diamond Mining in the BCLME Toward Integrated Environmental Management
Integrated Environmental Management, as it applies to marine diamond mining, is
evolving with steady improvement, but a few criticisms are warranted
Socio-economic Environment
EMPRs have generally not taken due cognisance of socio-economic impacts
Steps must be taken toward reallocating diamond mining revenue toward upgrading
infrastructure, stimulating development in the areas most severely affected by mining and
redressing racial imbalances in the industry
Biophysical Environment
Shortcomings in terms of biophysical environmental management include the broad-scale
nature of the baseline information, the desktop nature of most assessments and the high
taxonomic level at which assessments have been undertaken (i.e. individual species may
be ignored)
Environmental Management as a Whole
Cumulative impacts within the mining industry and amongst all users need to be
addressed more fully
Regular audits need to be undertaken of EMPRs to ensure that they include the latest
information and technology
Conclusions The Way Forward
In South Africa and Namibia, directed studies must be commissioned to address gaps in
knowledge to improve integrated environmental management of activities in the BCLME
The IEM process must be adopted in Angola and the necessary baseline information
collected before marine and coastal mining is initiated
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TABLE OF CONTENTS
Conditions of Use ...................................................................................................................... i
Scope ....................................................................................................................................... ii
Executive Summary ................................................................................................................ iii
1. Introduction..........................................................................................................................1
2. Historical Perspective..........................................................................................................2
3. Areas of Operation and Major Role Players........................................................................4
3.1 South Africa.......................................................................................................................4
3.1.1 Onshore Mining ..........................................................................................................4
3.1.2 Offshore Mining ..........................................................................................................4
3.2 Namibia .............................................................................................................................5
3.2.1 Onshore mining ..........................................................................................................5
3.2.2 Offshore mining ..........................................................................................................5
3.3 Angola ...............................................................................................................................5
5. Environmental policy and Legislation .................................................................................17
5.1 Introduction......................................................................................................................17
5.2 South Africa.....................................................................................................................17
5.2.1 Minerals Act, 1991 (Act 50 of 1991) .........................................................................17
5.2.2 Environmental Conservation Act, 1989 (Act 73 of 1989)..........................................17
5.2.3 National Environmental Management Bill of 1998....................................................18
5.2.4 Other Legislation Relevant to Environmental Aspects of Mining Activities...............18
5.2.5 Requirements for the Compilation of Environmental Management Plan Reports....19
5.3 Namibia ...........................................................................................................................22
5.3.1 Minerals (Mining and Prospecting) Act, Act 33 of 1992............................................22
5.3.2 Environmental Assessment Policy of 1995 and the New Environmental Management
Act.......................................................................................................................................23
5.3.3 Other Legislation Regulating Environmental Aspects of Mining ...............................23
5.3.4 Environmental Management Plan Reports (EMPRs) ...............................................24
6. Environmental Issues, Impacts and Mitigation ..................................................................26
6.1 Introduction......................................................................................................................26
6.2 Socio-economic Environment Positive Impacts ...........................................................26
6.2.1 Creation of Revenue and Employment.....................................................................26
6.2.2 Human Resource Development and Social Betterment ...........................................28
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6.3 Socio-economic Environment Negative Impacts..........................................................29
6.3.1 Shifting Emphasis from Onshore to Offshore Mining................................................29
6.3.2 Involvement of Small Scale Miners...........................................................................30
6.3.3 Promotion of Joint Management Ventures with Employees .....................................31
6.3.4 Reduced Revenue from Offshore Diamond Mining to Local Areas ..........................31
6.4 Biophysical Environment - Positive Impacts....................................................................34
6.4.1 Conservation of Flora and Fauna in Restricted Areas..............................................34
6.5 Biophysical Environment - Negative Impacts ..................................................................34
6.5.1 Environmental Impacts of Terrestrial Mining ............................................................35
6.5.2 Environmental Impacts of Beach Mining ..................................................................37
6.5.3 Environmental Impacts of Shal ow-Water Mining Operations (<30m depth) ............37
6.5.4 Environmental Impacts of Mid-water and Deep-water Mining Operations (>30m) ...39
6.5.5 Generic Impacts........................................................................................................41
7. Diamond Mining in the BCLME Toward Integrated Environmental Management ..........54
7.1 Socio-economic Environmental Management.................................................................54
7.2 Biophysical Environmental Management ........................................................................54
7.3 Environmental Management as a Whole ........................................................................55
7.4 Conclusions The Way Forward ....................................................................................56
8. Bibliography.......................................................................................................................58
9. People Consulted ..............................................................................................................62
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1. INTRODUCTION
The Benguela Current Large Marine Ecosystem (BCLME), situated off the west coast of
southern Africa, is one of 49 LME systems that have been described around the world. LMEs
are defined as large bodies of water (200 000-sq. km) with distinctive bathymetry,
productivity and trophically dependent populations. The Benguela Current LME is one of the
most productive of these systems, supporting an important global reservoir of biodiversity and
biomass of fish, sea birds and marine mammals.
Several issues of common concern to South Africa, Namibia and Angola, the three countries
bordering the BCLME, are commercial fishing, recreation, diamond mining, oil and gas
exploration and coastal zone development. These activities are putting escalating strain on
the BCLME. With the advent of environmental concern, most countries have drafted
legislation that seeks to ensure responsible and sustainable use of the environment for all
users. The efficacy of both the legislation and enforcement, however, remain in question. A
related concern is the potential for conflict between users of the BCLME, as escalating effort
and technologies will see increasing overlap between the various sectors. With a view to
resolving conflicts and responsible environmental management, there has been a call for an
integrated and co-ordinated approach to the management of this system. To this end, the
United Nations Development Programme has called for a Synthesis and Assessment of
Existing Information on the BCLME, reviewing activities in the BCLME, their impact on the
environment, and their management. This review will be used to assess the status quo,
identify gaps and shortcomings in the management of activities affecting the BCLME, and
direct further research, policy and funding through a Strategic Action Programme.
This document forms a part of the synthesis and assessment phase reviewing marine diamond
mining in the BCLME. Specifically, it traces the history and development of marine diamond
mining; outlines the key players and their areas of operation; describes the methods and
equipment employed in extracting marine diamonds; reviews the legislation relevant to
diamond mining activities; outlines how these methods impact the environment; reviews
conflict and mitigation; and finally, highlights gaps and shortcomings and suggests methods
by which integrated management of the BCLME can be achieved. Emphasis is placed on
marine-based activities, although terrestrial aspects are discussed briefly, as they also affect
future marine and coastal users.
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2. HISTORICAL PERSPECTIVE
Diamonds were formed aeons ago in the mantle of the earth, some 150-250 km below the
surface. They are formed of carbonaceoyus material, subject to extreme heat and pressure,
crystallised into diamonds as they were brought up to the surface in streams of molten
magma. This diamondiferous magma, known as kimberlite spewed out in various places over
the southern African subcontinent, solidifying on the surface and in magma pipes leading up
to the surface. Over geological time (ca. 80 million years), this kimberlite material gradually
eroded, with rivers carrying an estimated 3 billion carats of diamonds to the sea.
Concomitantly, river mouths meandered up and down the coast, thereby building up extensive
submarine deltas containing diamonds along much of the coast. Wave action removed much
of the lighter and softer material, concentrating the heavier and harder material, such as
diamonds, in beach terraces and paleo channels. Tectonic movements together with climatic
changes resulted in immense fluctuations in sea level, and consequently diamonds became
concentrated in a series of beaches or terraces both above and below the present day sea level,
each terrace corresponding to former static sea levels.
Diamonds were first discovered in South Africa in 1866 on a farm south of Kimberly. This
discovery was followed by further finds of both diamond-bearing kimberlite pipes and
alluvial deposits in the drainage system of the Vaal River. The first discoveries on the west
coast of southern Africa only occurred 42 years later, however, when a railway construction
worker, Zacharia Lewala, found the first diamond near Lüderitz in 1908. Picking up the shiny
stone, he passed it to his supervisor August Stauch an employee of the Deutsche Koloniale
Gesellenschaft (DKG) responsible for keeping the newly constructed railway between
Lüderitz and Keetmanshoop clear of sand. On the 20th of June 1908 Stauch reported his find
to the DKG and applied for prospecting licenses, which they granted. In January 1909 rich
deposits were found south of Pomona, which was soon followed by the discovery of deposits
in the Bogenfels region. Word soon spread and people flooded into the area and settlements
sprung up out of the desert almost over night.
At the time of the discoveries, South West Africa (SWA, now Namibia) was under German
jurisdiction, with the exception of the port of Walvis Bay and a series of 'guano islands' off
the coast. In September 1908 the German government granted the DKG the sole right to
search for and work mineral deposits between the Orange River in the south and 26ºS latitude
in the north stretching 100km inland. This area, which became known as the Sperrgebiet, was
fenced off and entrance was restricted to prevent the theft of diamonds. The Sperrgebiet
remains closed to unauthorised persons today.
The Germans were to remain in control of SWA until WW1 when the territory was handed
over to South Africa to Administer. In 1920 the Anglo American corporation of South Africa
gained control of the diamond interests in SWA forming the Consolidated Diamond Mines of
SWA (CDM).
The finds in the Lüderitz area inspired prospectors south of the Orange River in the new
Union of South Africa. Eventually these efforts paid off, with discoveries by Jack Carstens
near Port Nolloth in 1926. As mining and prospecting progressed in the Namaqualand region,
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Dr Merensky and Dr Reuning recognised the link between old marine terraces and diamond
deposits. Armed with this information they soon discovered numerous rich deposits south of
the Orange River mouth. These finds brought prospectors from the Lüderitz area to the
beaches immediately north of the Orange River mouth. Here they were to find significant
diamond deposits, and the focus of mining in the Sperrgebiet consequently shifted south, to
what is today known as Mining Area 1.
It was not until 1961 that diamonds were mined offshore on the west coast of southern Africa.
Sam Collins a rich Texan whose company specialised in submarine pipelines became
interested in the theories that rich diamond deposits lay offshore of the Orange River mouth.
His pipeline experience enabled him to develop techniques for dredging diamonds from the
seabed. The feasibility of this venture was doubted, however, as it was accepted at that time
that the deposits could not be mined economically. Sam Collins was not deterred and
tenaciously stuck to the task, proving his critics wrong. His company Marine Diamond
Company (Pty) Ltd successfully mined payable deposits in shallow water off Chamies and
Bakers Bay. In the process he experimented with various sea going vessels, from small
fishing boats, to large mining barges, to a converted 70 m ex-US Navy tank landing craft,
using a combination of airlifts and centripetal pumps. Initially De Beers had thought that this
would not be economical but admitted their error, eventually buying a controlling share of
MDC in 1965. Soon after however, the diamond market slumped and MDC ceased offshore
mining operations in 1971. Smaller scale operators continued to mine from converted fishing
vessels, however, while De Beers continued prospecting in deep water areas.
Small-scale shallow water operations continued to increase steadily over the years, but deep-
water offshore mining operations only really started again in the early 1990s. These deep-
water operations now represent the pinnacle of technological development in the diamond
mining industry, requiring dedicated mining vessels, complex electronic navigation systems
and specialised remotely operated mining tools. Onshore diamond mining operations along
the coast are also a far cry from their early beginnings when diamonds were first collected by
hand on moonlit nights. At first diamonds were excavated manually using shovels, which
were then screened by various sieving techniques. Gradually mechanical excavators and
concentrating devices were employed to process the large volumes of sediment required.
Today large mining plants process millions of tons of gravel per year, utilising heavy-media
separation, cyclones and x-rays in the concentration process.
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3. AREAS OF OPERATION AND MAJOR ROLE PLAYERS
The areas in which mining occurs in the Benguela ecosystem have been divided into 5 distinct
categories and is discussed under two broad headings for the purposes of this document.
These are defined as:
Onshore
Terrestrial mining mining above the high water spring tide mark (HWS)
Beach mining mining of beaches into the subtidal through the construction of sea walls
(coffer dams)
Offshore
Shallow water mining Operations to a depth of 30 m, further divided into:
Shore based mining divers operating from the shore
Boat-based divers operating from small boats
Mid-water mining 30-75 m depth utilising remotely-operated tools, mostly air-lift
dredges
Deep-water mining Operations deeper than 75 m, using customised mining vessels and
specially designed remotely-operated mining tools
Diamond mining occurs across all of the above mentioned categories in distinct concession or
license areas. Concession areas are allocated differently in Namibia and South Africa and
these are discussed separately below with particular reference to the major role players
involved.
3.1 South Africa
3.1.1 Onshore Mining
Terrestrial concessions, including beach mining concessions, are mined between the Orange
River mouth and an area slightly south of the Olifants River. Two major companies, Alexkor
(a parastatal organisation which is currently being privatised) and De Beers Namaqualand
(Pty) Ltd dominate diamond production along the shores of Namaqualand and the Northern
Cape. Alexkor operates from the Orange River mouth to just south of Port Nolloth, while De
Beers operates from Alexkor's border to slightly north of the Olifants River (Figure 1).
Around these major concessions are a number of smaller concessions operated by companies
like Trans Hex Investments (Pty) Ltd.
3.1.2 Offshore Mining
In South Africa the offshore concessions stretch from the border with Namibia off the Orange
River mouth, to an area just south of Saldanha Bay (Figure 2). Each concession area is further
split into four sub-areas in an offshore direction (Figure 3). The `a' concession extends from
low water to 31.5 m offshore, while the `b' concession extends from the western boundary of
the `a' concession to a co-ordinated boundary approximately 5 km offshore (less from
concession number 15-20). The `c' concession runs from the western boundary of `b'
concession to the 200m isobath and the `d' concession runs from the western boundary of `c'
concession to the 500m isobath.
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The major players, including concession owners and concession operators in the offshore
diamond industry of South Africa are listed in Table 1. Three companies dominate the
offshore diamond industry: De Beers Consolidated Mines (mainly mid- to deep-water
concessions), Alexkor (mainly shallow-water concessions) and Trans Hex (shallow and deep-
water concessions). Other significant players are BHP-Benguela Nominees, Ocean Diamond
Mining, De Beers Marine (undertakes all De Beers offshore operations), Namagroen
prospecting, Benguela Concessions and Marine 17 Mining.
3.2 Namibia
3.2.1 Onshore mining
Namdeb Diamond Company (Pty) Ltd (formally Consolidated Diamond mines of SWA)
controls mining of the `Sperrgebiet' under the Namdeb Agreement (1994). They have
exclusive rights to prospect for and mine diamonds within the Sperrgebiet until the year 2010.
The Sperrgebiet stretches from the Orange River in the south to latitude 26ºS in the north,
extending 100 km inland (Figure. 4). Namdeb is a 50/50 partnership between De Beers and
the Namibian government and is responsible for the majority of onshore production in the
southern parts of the Sperrgebiet (immediately north of Oranjemund), in their beach mining
operations. Some smaller contractors also operate onshore on the Namibian coast, but they
mine predominantly in the northern license areas.
3.2.2 Offshore mining
Namibian offshore concessions cover the full length of counties coastline, extending from the
Orange River to the Kunene (Figure. 5). Concession boundaries are not regulated by depth as
in South Africa. Onshore mining licenses extend 3 km offshore, and Namdeb thus controls
most of the shallow water mining activities (with the exception of the island concessions,
which are operated by ODM). Offshore licenses are issued after specific application to
government, which must include the co-ordinates of the intended mining area.
he major companies involved in the Namibian offshore diamond industry are Namdeb, Ocean
Diamond Mining (ODM)(of which Eiland Diamante is a subsidiary), the Namibian West
Coast Mining Company - Diamond Fields International (DFI) group, the Namibian Minerals
Corporation (NAMCO) - Arena Mining group, and Tidal Diamonds (an associate company of
Namdeb). Numerous other companies like De Beers Marine, Yam Diamonds (who also own
their own concession) and Windvogel Diamonds mine mainly on contract to the larger
players.
3.3 Angola
No coastal or offshore mining currently occurs in Angola. Prospecting and mining activities
are continuing inland but the Angolan government has issued no licenses for coastal areas,
preferring to concentrate their efforts on terrestrial operations.
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Figure 2. Map of the offshore concession areas of the Republic of South Africa. A key to the
concession holders and operators is provided in Table 1 (provided by De Beers Marine).
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Table 1. Diamond mining concession holders and operators in the Republic of South Africa.
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Figure 5. Major coastal and offshore diamond mining concession areas of Namibia. (Original
coverage provided by B. Beuthin, Geological Survey, Ministry of Mines and Energy,
Namibia).
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4. Mining Techniques and Operational Practices
Diamonds in the southern African coastal region are concentrated in the vicinity of paleo
drainages, in bedrock gullies, potholes and depressions, along offshore ridges and south
facing paleo bays, headlands and aeolian transport corridors. The greatest concentrations of
diamonds usually occur near or on the bedrock. In order to retrieve diamonds, the overlying
marine and terrestrial deposits (overburden) first has to be removed, followed by the
collection of the diamondiferous gravel below. The techniques used to remove the
overburden and to collect the gravel varies considerably according to where the gravel is
located, the richness of the ore and the thickness of the overlying deposits. Basic distinctions
can be drawn between operations conducted on land, and in shallow-, mid- and deep-water
areas. These are elaborated separately below.
4.1 Terrestrial and Beach Mining
Onshore mining activities immediately adjacent to the coast are undertaken mostly using
heavy-duty earth moving equipment, operational in large-scale open cast mines. Five fairly
distinct phases are involved in the mining operation, including prospecting, overburden
stripping, excavation of terrace gravels, mineral processing and sorting. The precise methods
used in each of these phases has been developed and improved upon over the years and varies
somewhat between areas and from company to company. What follows here is a generic
description of the methods currently in use.
The major form of prospecting involves the drilling of small diameter percussion holes,
followed in some cases with large diameter auger drilling and/or the excavation of trenches of
varying depth and length. Overburden material from the trenches is generally deposited in
overburden dumps on the surface next to the trenches and the underlying gravel is removed
for processing. These three methods of prospecting are used to locate, intercept and sample
the terrace gravels. As terraces have eroded erratically and diamond occurrence is sporadic,
prospecting is generally undertaken in a closely spaced pattern in order to delineate the ore
bodies accurately.
The next phase, overburden stripping, is done using a variety of earth moving machines
including bowl scrapers, bulldozers, mass excavators and in some areas bucket-wheel
excavators. Excavation is generally undertaken on a block-byblock basis and the overburden
removed is dumped into trenches from which the underlying gravel has been removed; piled
into overburden dumps; or used to create a seawall, extending the shoreline several hundred
meters out to sea.
By constructing protective seawalls, gravels up to 20m below sea level and several hundred
meters beyond the present shoreline can be recovered using terrestrial operations. Once the
overburden has been removed, the bulk of the diamond bearing gravel is excavated
mechanically. Deposits remaining in gullies and potholes on top of the bedrock are then
swept and collected manually using pick, broom and shovel teams or using suction
equipment. All the ore is transported to treatment plants where the gravel is crushed, washed,
sieved and concentrated in a solution of seawater and ferrosilicone using heavy media
cyclones. The gravel concentrate is then dried, sorted by means of x-ray machines and finally
the diamonds picked out by hand. Gravel, from which the concentrate has been extracted, is
disposed on tailings dumps, while water containing sand and fine sediment is discharged into
slimes dams or pumped directly into the sea. Most of the ferrosilicone is recovered before it
leaves the plants and is recycled in the process.
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4.2 Shallow-water Mining
Shallow-water mining operations are conducted using small-scale, diver assisted suction equipment.
Shore-based operators generally operate in the intertidal down to a depth of around 10 m, while the boat-
based operators usually work in the 10-30 m depth range. This delineation is not strict, however, with the
boat-based miners moving inshore in areas where access to the shoreline is difficult (where sea-cliffs
abut directly onto the shore or in the offshore islands concessions).
The techniques used for shore- and boat-based operations are very similar, expect that boat-
based operations generally employ larger equipment and more divers. A shore-based
operation typically consists of 2-3 divers, their assistants and a tractor modified to drive a
rotary classifier and centripetal pump to which an eight inch suction hose is attached. The
divers, operating on surface-supplied diving equipment, guide the terminal end of the hose
into the gravel deposits, which are sucked up and delivered directly to the classifier.
Concentrate is bagged and brought to central sorting houses onshore. Large rocks are often
moved by the divers (or pulled up onto the shore using a tractor) to allow the pump nozzle to
reach deep layers of gravel where the heavy diamonds settle. Coarse material is allowed to
build up on the shore, while fine material is returned to the sea. In some instances, kelp may
be cut to facilitate access to shallow inshore ore bodies.
A typical boat-based operation consists of a 10-15m vessels with a 5-8 man crew, of which 2-
3 are divers. The vessels are equipped with 1-2 hoses per boat, with the duration of their
activities limited to daylight hours for 3-10 diving days per month. Some 20-22m vessels,
offering surface decompression facilities and with 8-11 man crews, are also operational.
These larger boats are able to work on a 24h basis for up to 21 days per month. However, due
to the water depths involved, diving in nearshore mining operations necessitates strictly
enforced decompression routines thereby limiting bottom working time. The diamondiferous
concentrate is bagged onboard, and brought ashore for final processing in shore-based jig
plants and sorting houses. On vessels operating further afield, the initial jigging may be
conducted on board. Oversize tailings are either returned directly overboard to the mined area
or transported further offshore in inflatable boats and dumped. The fines are washed
overboard. In the mining process large rocks may either be exposed, or removed by divers to
allow the suction nozzle to reach deeper gravel layers. The rocks are sometimes accumulated
by the divers into rock piles.
Shallow-water mining is opportunistic in nature and highly dependent on weather and sea conditions.
Due to the difficulty of employing modern geophysical survey techniques and large-boat sampling in
shallow water nearshore areas, exploration and investigation in water depths <30m, is generally limited to
irregular side-scan sonar mapping and prospecting dives from the shore or from small boats. These
surveys are often based on historical recoveries. Small-scale sampling is undertaken by diver-assisted
dredging, the gravel being bagged and processed ashore. Many of the nearshore operations are
currently being enhanced by more sophisticated tracking and positioning systems to help focus efforts
on the more productive areas. Both shore- and boat-based miners generally only operate in exposed
rocky shore areas where gravel is pumped from deeper gullies, or on the edges of sandy bays where the
layer of overburden is relatively thin. Mining off sandy beaches is generally unprofitable for these small-
scale operators due to the large volumes of overburden that have to be removed before it is possible to
gain access to the heavier gravel. However, the use of underwater `blowers' to shift overlying fine
sediment, initially used only when operating in shallow water (<8 m depth), is becoming more widespread
as it allows for the exploitation of gravel deposits which were previously uneconomic to recover.
4.3 Mid-Water and Deep-Water Mining
A variety of methods are used to mine marine diamond resources in water depths >30 m,
which may be split into mid-water operations (down to a depth of 75 m) and deep-water
operations (down to a depth of 200 m). The geophysical survey and prospecting methods in
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use are similar for both regions, and include high resolution side-scan sonar, shallow
reflection seismic profiling, video, vibrocoring, rock drilling and grab sampling. The resulting
data are used to produce maps of the seabed geomorphology, sediment and bedrock
distribution, bathymetry and sediment type and thickness profiles. From these maps, areas of
unconsolidated sediment suitable for sampling are identified, and a sampling grid is
positioned over the area. Surveying activities are usually ongoing in order to develop
geological models encompassing all the concession areas held by a company. Precise
sediment sampling using penetrating tools is subsequently carried out on the grid.
Once a mineable ore reserve has been identified, bulk sampling is conducted in the sampling
grid. The bulk sampling process is done in a scattered grid pattern and is similar to mining but
on a smaller scale. Mineable marine ore reserves are divided into rectangular blocks of 50x50
m which are then systematically and contiguously dredged. While some block groups may
only be a few 100 m long, others can stretch 1-2 km in length. Commonly, Wirth Drill or
seabed crawlers are used to clear 50 m2 areas of sea floor to bedrock level. Seabed crawlers,
equipped with anterior articulated cutting and/or sucking devices are lowered onto the seabed
on a hoist rope, with power and signal umbilical cable attached and controlled remotely from
a surface support vessel. The vehicle mines by systematically advancing along a specific
`lane' achieving precise coverage of the area to be mined. This mining tool is especially
suitable on flat areas with few boulders and is capable of mining sediment thicknesses of up
to 5 m in water depth of up to 150 m. The Wirth Drill is a vertically mounted, larger diameter
drill-head used to recover diamond bearing gravel in a systematic pattern of overlapping
circles over the mining block. The drill is capable of drilling through more than 5 m of
sediment and penetrating rock in water depths to 150 m.
Mining using the above techniques involves the removal of only the unconsolidated
superficial sediments. The dredged sediment-slurry is airlifted to the surface, discharged into
a slotted circular tower and dropped onto a multi-decked screen, which separates the oversize
and undersize fractions. These are immediately discarded overboard, care being taken to
prevent covering unmined areas. Of the material airlifted to the surface, 99.9% is returned
directly to the sea. Re-mining of an area occurs only when the initial coverage of a block by
the mining tool was insufficient.
The fraction of interest (plantfeed) is fed through a ball mill to fragment the shell and clay
components, before being mixed with ferrosilicone and pumped under pressure into a dense
medium separation plant. Low-density materials (floats) are separated from the concentrated
plantfeed and discarded overboard. The remaining high-density fraction is dried and passed
through an x-ray sorting machine to separate the diamonds. Non-fluorescent material is
discarded overboard and the fluorescent fraction is automatically sealed in cans. On some of
the smaller offshore vessels the high-density fraction is still hand sorted for diamonds.
The prospecting and mining vessels currently employed in offshore diamond recovery in
Namibian and South African waters are semi-mobile platforms on a dynamic positioning
system, or self-mooring systems comprising three to four anchors. These ships, which range
in size from 50 m (26 crew) prospecting vessels to 140 m (90 crew) mining vessels, are fully
self contained mining units operating on a 24 h basis through 11 months of the year.
Several new techniques are planned for the future that will reduce mining costs and allow for
the exploitation of lower grade ores in the mid- and deep-water zones. These include jack-up
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rig platforms and bulk dredging operations. Jack-up rigs will be semi-mobile platforms
housing the separation and recovery plants, which are fed slurried gravel via flexible hoses
attached to multiple dredge crawlers. These platforms will be moved as required (probably
not more than once or twice per year) and will be serviced by ship or helicopter from the
nearest logistical base.
Massive sheet gravels occur in some mid- and deep-water areas that are uneconomic to
exploit using currently available methodology. Plans are afoot, however, to begin exploiting
this low-grade ore using high volume suction hopper dredges. These plans call for the use of
large dredges on which under- and over-size material will be screened to separate hoppers,
while plant feed material is transferred to processing plants at sea or on the shore. Tailings
disposal would be back to the sea in designated tailings areas.
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5. ENVIRONMENTAL POLICY AND LEGISLATION
5.1 Introduction
Numerous legislative Acts have been promulgated to regulate and mitigate effects of mining
and associated activities in South Africa and Namibia. The main environmental provisions of
Acts pertinent to the management of activities affecting the BCLME are described below. At
the time that this report was prepared, no information was available regarding legislation
controlling the exploitation of minerals in Angola.
5.2 South Africa
5.2.1 Minerals Act, 1991 (Act 50 of 1991)
Prior to commencing prospecting or mining operations, section 39 of the Minerals Act
requires a "layout plan and rehabilitation programme", now referred to as an Environmental
Management Plan Report (EMPR) to be submitted to the regional director Department of
Mines and Energy (DME). Prior to approval of an EMPR, the regional director must consult
with Cape Nature Conservation and/or Sea Fisheries Research Institute for comment.
Exemptions from EMPRs may be granted in certain circumstances, however. Procedural,
format and performance assessment requirements for these documents are detailed in Section
5.2.5 below.
The Act requires the holder of the prospecting permit or mining licence to rehabilitate the
"surface of land" to the Regional Director's satisfaction and to do this as an integral part of,
and simultaneous with, prospecting or mining operations. On termination of prospecting and
mining activities, all structures not required by the landowner are to be demolished and all
debris removed. The mining licence holder is responsible for rehabilitation, until such time
that the Regional Director issues a closure certificate. Before a mining or prospecting licence
is granted, the applicant must demonstrate the financial ability to pay for rehabilitation by
establishing a rehabilitation trust fund, submitting bank guarantees, lodging cash with the
DME or by other mutually acceptable arrangements.
5.2.2 Environmental Conservation Act, 1989 (Act 73 of 1989)
Regulations promulgated in September 1997 under the Environmental Conservation Act
1989, list activities which require an Environmental Assessment and the procedures to be
followed. Although mining per se is not a listed activity (as it is in Namibia's Draft
Environmental Management Bill 1998) several land use activities ancillary to mining are
listed. These include roads, harbours, structures and reclamation of land below the high water
mark, dams, onshore infrastructure and services (sewage treatment, waste disposal), and
industrial buildings.
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5.2.3 National Environmental Management Bill of 1998
Provisions of the Environmental Conservation Act, 1989 and its regulations relating to listed
activities and compilation of environmental impact reports will be repealed by promulgation
of the National Environmental Management Bill of 1998. The aim of this bill is to co-
ordinate the activities of all listed state departments having an influence on the environment,
and to allow for revision of regulations on listed activities and environmental management
procedures. Until new regulations on procedures, report contents and listed activities are
gazetted, existing regulations for EIAs under the Environmental Conservation Act, 1989 and
regulations for EMPRs under the Minerals Act 1991 remain in force. EMPR requirements
are currently being revised by the DME in accordance with the National Environmental
Management Bill, and are due for implementation in June 1999 (MME pers. comm.).
5.2.4 Other Legislation Relevant to Environmental Aspects of Mining Activities
Other statutory acts and regulations applicable to marine mining activities and employee
behaviour on land and at sea are listed and described briefly below:
Pollution at Sea
a) Prevention and Combating of Pollution of the Sea by Oil Amendment Act 24 of 1991
regulates oil pollution from ships at sea
b) Marine Pollution (Control and Civil Liability) Act 6 of 1981 (and Marine Notices)
establishes reporting requirements and procedures for oil spills and oil bunkering
c) 1973 Convention for the Prevention of Pollution from Ships (MARPOL) controls all
waste disposal at sea (oil, hazardous waste, solid waste (plastics, tins, glass, organic
matter etc, and sewage). RSA is a signatory on this convention.
d) National Water Act 36 of 1998 controls discharge of tailings, and sea and fresh water
pollution on land
Air Pollution
a) Montreal Protocol on Substances that Deplete the Ozone Layer was adopted in
1987 to which signatories undertake to control and limit the consumption of
chlorofluorocarbons (CFCs) and not to import CFCs from states which are not parties
to the Protocol.
Use of Harbours and Ports, Landing Facilities and Specific Tidal Rivers by Vessels
a)
Marine Living Resources Act 18 of 1998 and its regulations of September 1998
regulates use of fishing harbours by vessels and staff
b)
South African Transport Services Act 65 of 1981 regulates use of harbours under
Portnet's jurisdiction (e.g. Port Nolloth)
c)
Sea Shore Act 21 of 1935 and Environmental Conservation Act 73 of 1989
controls construction of structures below high water mark (e.g. jetties)
d)
Nature and Environmental Conservation Ordinance 19 of 1974 regulates boating
on Verlorenvlei, the Olifants River, and lower Berg River
Vehicle Access to Coastal Zone and Other Sea Shore Activities
a)
Control of Vehicles in the Coastal Zone* (Regulations under Environmental
Conservation Act 73 of 1989) requires implementation of a permit system for beach
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use by vehicles, restricts vehicle use to non-sensitive areas (e.g. below high water
mark, away from dunes) and to existing tracks
* Specifically excludes approved diamond mining activities, although MME has
pledged to apply these regulations through EMPRs (MME pers. comm.)
b)
Regulations and bylaws under the Sea Shore Act 21 of 1935 promulgated by local
authorities controls beach access, littering, camping, bathing, launching of boats, and
in the case of the West Coast District Council, disturbance of animals, birds and plants
below the high water mark
Disturbance or Damage to Natural and Cultural Resources
a)
Marine Living Resources Act 18 of 1998 and its regulations of September 1998
licences required for cutting and removal of kelp, disturbance or collection of lobsters;
and all other forms of fishing
b)
Sea Birds and Seals Protection Act 46 of 1973 controls disturbance of sea birds
and seals on islands (no-one may set foot on an island without permission)
c)
Nature and Environmental Conservation Ordinance (19 of 1974) regulates
hunting; disturbance of wild animals, collection and damage to plants, pollution of
inland waters
d)
United Nations Convention on Biological Diversity conservation of biodiversity,
sustainable use of its components, and equitable share of the benefits arising from the
use of genetic resources.
e)
National Monuments Act 28 of 1969* disturbance and removal of archaeological
and palaeontological sites and shipwrecks
* This act excludes mining from disturbance to archaeological sites except shell
middens and cave contents (i.e. the majority of sites in the coastal zone)
Health and Safety of Employees and Vessels
a)
Regulations under Mines and Works Act 27 of 1956 regulates diver
qualifications, diving equipment and diving procedures
b)
Merchant Shipping Act 57 of 1951 regulates safety and licensing requirements for
vessels
c)
Marine Traffic Act 1981 regulates traffic of marine vessels
d)
Wreck and Salvage Act regulates liability for removal of wrecks
5.2.5 Requirements for the Compilation of Environmental Management Plan
Reports
Procedures
Compilation of EMPRs are based on Integrated Environmental Management (IEM) and
involves but are not necessarily restricted to:
1.
Consultation with the Director: Mineral Development of DME and all relevant
authorities to determine the scope of the EMPR
2.
Scoping with other interested and affected parties to further define the scope of the
EMPR through identification of issues of concern
3.
Assessment and Evaluation of Impacts (involving I&APs)
4.
Compilation of a plan for management of impacts (involving I&APs)
5.
Submission of a draft EMPR to DME who will circulate it to relevant Government
departments and make it available to the public
6.
Revision and resubmission (if needed)
7.
Approval unless further mitigatory planning is required and revisions necessary.
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Contents of EMPRs
As a minimum, EMPRs for offshore mining should be separated into three parts: Part A
(EIA); Part B (EMPR) and Part C (Supporting References and Statutory Requirements) and
should contain:
1. General
Information
a) Contact addresses and numbers,
b) Maps showing concession area, proposed mining area, location of mining and onshore
logistical facilities, other projects and activities in adjacent areas
c) Description of proposed project (production rate, life expectancy, timetable of project
phasing and sequencing)
2. Project
Motivation
a) Local, regional and national socio-economic benefits (mine expenditure, revenue,
multiplier effects, infrastructure benefits etc.
b) compatibility with other policies, plans and land users
c) consideration of project alternatives
3.
Detailed Project Description for all offshore and onshore activities including
infrastructure and support facilities; mining methods including processing operations,
transportation requirements and methods; all waste emissions and disposal methods;
chemicals to be used; and use of water and electricity.
4.
Description of Pre-mining Environment to provide baseline information to establish a
reference for determining and evaluating impacts, and design of mitigation measures.
The following environmental aspects should be described and mapped: geology and
sediment; oceanographic patterns, physical nature of surrounding areas (coastal zone,
sensitive areas e.g. wetlands, islands, dunes etc); fauna and flora that occur in the area
and may be affected, particularly benthic organisms; climate; sites of cultural
resources (archaeology, shipwrecks etc); recreational areas and transport routes;
mariculture areas; fishing areas, and other marine harvesting areas e.g. kelp.
5.
Environmental Impact Assessment should include a quantitative and qualitative
analysis of the nature of impacts of all project activities on all components of the
natural, socio-economic and cultural environment before and after mitigation for each
phase of mining: construction, operation, decommissioning and post closure. Each
impact should be evaluated using the following criteria: nature; time of occurrence;
spatial extent; duration; intensity; probability and significance.
6.
Environmental Management Plan. Measures to mitigate the effect of each impact on
each environmental component (identified in Part A of the report) for each project
phase should be described. The plan must include rehabilitation of disturbed areas,
pollution control, emergency procedures, links with existing contingency plans, future
public participation strategies, and outline of the decommissioning strategy.
7.
Monitoring of EMP Performance and Reporting Requirements. Describe the
monitoring programmes to be implemented for each phase, and include a statement of
objectives, targets for compliance, description of physical monitoring systems and
frequency of monitoring. Describe the auditing system that will be followed to assess
EMP performance (adequacy and appropriateness) and the reporting procedures to be
followed (type, frequency and format of reports and other information to be
submitted).
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8. Financial
Provision. Indicate what financial provisions (complying with regulations
under the Minerals Act) have been made to implement environmental management
and rehabilitation.
9.
Supporting Documentation and Statutory Requirements. Include in this section
permissions granted under other statutes, applications submitted, and future statutory
requirements.
EMPR requirements for a) concessions and surf zone mining
As an alternative to the above, a tabular format for EMPRs for companies mining in the a)
concession and surf zone areas only can be completed and submitted together with a locality
map (1:50 000 map), and a layout plan showing the location of all infrastructure including
access roads.
Operating and Rehabilitation Requirements of the EMP
The DME has compiled a set of standard operating and rehabilitation requirements for mining
in the a) concession area and surf zone, which are legally binding on the mining operation
after approval of the EMP has been given. These standards cover issues such as the
requirement to update maps on a quarterly basis, minimum infrastructure requirements for
construction camps, use and maintenance of access roads to beach and campsite areas; waste
disposal; water pollution control; location of processing areas; deposition of tailings onshore
and at sea, and rehabilitation.
Compliance with EMPRs: Performance Assessment and Monitoring
Regulations for EMP Performance Assessment (PA) and Monitoring have been gazetted
under the Minerals Act. These regulations stipulate the need for holders of prospecting and
mining authorisations to undertake ongoing monitoring of the EMP and to compile
performance assessments for submission to the Director: Mineral Development. EMP
performance assessment and reporting should be done according to the period specified in the
EMP; annually, or as agreed by the Director: Mineral Development. The PA report should
contain information on the period applicable to the PA; procedures used for the assessment;
information yielded from monitoring; criteria used in evaluation performance and the results;
and recommendations on rectifying deficiencies identified and areas of non-compliance.
Responsibility for PA lies with the prospecting/mining authorisation holder and may be done
by independent qualified consultants. Where a PA report is deemed inadequate by the
Director: Mineral Development, the holder may be required to repeat the whole or relevant
aspects of the EMP PA and resubmit a revised report or appoint an independent team to do so.
A final EMP PA is required where closure of a mine is intended and should accompany or
precede a closure application. The final PA will be assessed to ensure that all relevant
legislation has been complied with; closure objectives as described in the EMP have been met
and all residual and latent environmental impacts have been identified and arrangements
finalised for managing their risk and/or occurrence.
The regulations do not specify whether the PA reports are circulated to other relevant
government departments for comment prior to their approval by the Director: Mineral
Development. PA reports are available on request.
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5.3 Namibia
5.3.1 Minerals (Mining and Prospecting) Act, Act 33 of 1992
Application and Granting of Mining Licences
An applicant for a mining licence must comply with the provisions of the Minerals (Mining
and Prospecting) Act, Act 33 of 1992. Applicants are required to estimate the effect of
mining or prospecting on the environment and the steps to be taken to counteract such effects.
In line with the Minerals (Mining and Prospecting) Act, Act 33 of 1992, prior to consideration
of a mining licence, the Minister may require an environmental impact study. Alternatively,
the holder of a mining licence must prepare an environmental impact assessment (in a form
determined by the Commissioner) before any mining or prospecting is undertaken. If
pollution is likely to be caused by mining, an environmental management plan (EMP) is
required.
The minerals act allows for various types of prospecting and mining licences, issued by the
Mining Commissioner, covering both small-scale and formal activity:
Mining Claims available to Namibian citizens only, these claims are for the
development of small-scale mines and mineral deposits. Up to a maximum of ten claims
can be held at any one time, each valid for three years (with a possible two-year
extension).
Reconnaissance Licences designed for regional, mainly remotely sensed exploration to
facilitate the identification of exploration targets. Valid for six months on a non-
renewable basis only.
Exclusive Prospecting Licences for exclusive exploration rights in areas up to 1000
km2. Valid for three years, but can be extended twice for two-year periods, but not
beyond seven years without ministerial approval.
Mining Licences grant exclusive mining rights on a piece of property for 25 years or the
life of the mine, with renewals valid for 15-year periods. Holders are required to
demonstrate financial and technical ability to develop and operate a mine.
Mineral Deposit Retention Licence allows an exploration company to retain tenure on a
prospecting licence, mining licence or mining claim without mining obligations. Valid for
five years with two year renewal periods.
Responsibility of Licence Holders
Social obligations of mineral licence holders to employees and to Namibia include: the need
to give job preference to Namibian citizens possessing appropriate qualifications; conduct
training programmes; use products produced and services available in Namibia, and co-
operate with other Namibians involved in the mining industry to aid skills development.
The licence holder is ultimately responsible for all actions of subcontractors and must ensure
that all licence conditions are equally applied to subcontractors.
Environmental Protection
Provisions of the Minerals (Prospecting and Mining) Act relating to environmental protection
and rehabilitation are weak and unlikely to enforce compliance. Abandonment of a mining or
prospecting area stipulates the need to give written notice to the Commissioner; to demolish
accessory mining works (unless required by the landowner), and to "take all such steps" to
"remedy to the reasonable satisfaction of the Minister any damage" caused by the mining or
prospecting operation to the "surface of, and the environment on, the land in the area in
question". Further, contravention of these provisions may incur a fine not exceeding R8000
which is unlikely to be a deterrent to non-compliance.
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Issuance of mining or prospecting licences requires the holder to sign a Pro-forma
Environmental Contract with the Government of Namibia (represented by the Ministry of
Environment and Tourism, the Ministry of Fisheries and Marine Resources and the Ministry
of Mines and Energy). This contract obliges the holder to apply the Environmental
Assessment Policy (see below) and to reduce and mitigate all environmental damage and to
leave the environment in a reasonable state. The contract requires the licence holder to
submit a bi-annual Environmental Report documenting compliance with the submitted and
approved EMP.
5.3.2 Environmental Assessment Policy of 1995 and the New Environmental
Management Act
Namibia's Environmental Assessment Policy, compiled in 1995 by the Ministry of
Environment and Tourism, lists the activities for which an environmental assessment is
required (which includes mining, mineral extraction and mineral beneficiation) and describes
the procedure to be followed for undertaking and compiling them. The Ministry of Mines and
Energy and the Ministry of Fisheries and Marine Resources do not have their own set of
requirements in this regard.
Recently an Environmental Management Act (Act X of 1998) has been compiled which
prescribes the need for environmental assessments for listed activities and outlines their
minimum requirements. Listed activities relating to marine mining include: mining and
mineral extraction, the construction of harbours and associated structures, structures below
the high water mark, reclamation of land below the high water mark, the erection of buildings
and structures for industrial activity, construction of sewage treatment plants and dams or
reservoirs, and the construction of waste sites or facilities for waste treatment.
Environmental assessments are submitted to, and reviewed by, the Competent Authority and
Environmental Commissioner. The latter, after full consideration, and possibly further
consultation and external review, submits the EA with his/her recommendation to a
Sustainable Development Commission. The Sustainable Development Commission
(represented by officers from all key ministries, sustainable development specialists and
NGO representatives) is responsible for issuing or refusing the granting of an Environmental
Clearance, with or without conditions.
According to the Ministry of Environment and Tourism (MET) (Dohogne pers. comm.) a
flexible system for environmental assessments and management plans is followed for mining
whereby depending on the phase of the companies programme further environmental
information is requested. The different mining phases and requirements are:
Survey activities:
Simple environmental contract
Sampling:
EMPR including monitoring programme
Mining:
EA including EMPR and monitoring programme
5.3.3 Other Legislation Regulating Environmental Aspects of Mining
Activities undertaken during marine mining are regulated by legislation dispersed through
several Government Acts and Regulations. Several South African acts applicable in Namibia
have not been altered since Namibia obtained independence in 1991. However, in South
Africa some of these (e.g. the Water Act) have been revised while others (e.g. the National
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Monuments Act) are in the process of revision. Pertinent statutory legislation relevant to
marine mining in Namibia is listed below:
Pollution at Sea
a)
Sea Fisheries Act 29 of 1992 regulates pollution at sea and controls disposal of fish
and household waste from ships; disturbance of rock lobsters marine invertebrates and
aquatic plants, and restricts areas of seabed damage
b)
Prevention and Combating of Pollution of the Sea by Oil Amendment 24 of 1991
regulates oil pollution from ships at sea
c)
1973 Convention for the Prevention of Pollution from Ships (MARPOL)
controls all waste disposal at sea (oil, hazardous waste, sewage and solid waste)
d)
Water Act 54 of 1956 controls tailings discharges and sea and fresh water pollution
on land
Disturbance or Damage to Natural and Cultural Resources
a) National Monuments Act 28 of 1969 controls disturbance of shipwrecks and
archaeological deposits, such as shell middens and cave contents
b) Sea Birds and Seals Protection Act 46 of 1973 controls disturbance of sea birds and
seals on islands
c) United Nations Convention on Biological Diversity regulates conservation of
biodiversity, sustainable use of its components, and equitable share of the benefits arising
from the use of genetic resources.
Harbour Regulations
a)
Namibian Ports Authority Act 2 of 1994 gives Namport the responsibility of
protecting the environment within the harbour area
b)
Maritime Notice No 4 of 1994 provides rules and procedures for collecting garbage
in Namibian Waters.
Security
a) Diamond Industry Protection Act 17 of 1939 as amended tables laws relating to
regulation, control, development and protection of the diamond industry in Namibia
and illegal entry into prohibited areas. This act will soon be replaced by the New
Diamond Bill to be tabled in March 1999.
Employee Regulations
a)
Labour Act 6 of 1992 provides conditions of employment for employees of
Namibian companies and Occupational Health and Safety Regulations. Parts of this
Act are soon to be repealed and replaced by the Mine Health and Safety Regulations to
be tabled as an amendment of the Minerals Act, 1992.
b)
Immigration Control Act 7 of 1993 regulates employment and issuance of work
permits and obliges employers to give job priority to Namibians.
5.3.4 Environmental Management Plan Reports (EMPRs)
Namibian legislation requires that all new applicants for mining licences prepare an Environmental
Management Plan. No specific guidelines exist for compiling EMPRs, and these are usually assessed
according to the international literature and according to the specific programme proposed by the Mining
Company. Since South African consultants compile most of the EMPRs, the South African EMPR
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guidelines (section 5.2.5) are usually followed.
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6. ENVIRONMENTAL ISSUES, IMPACTS AND MITIGATION
6.1 Introduction
In the search for and extraction of ore bodies, the diamond mining industry by its very nature
exploits the environment. Large amounts of sediment need to be removed and processed,
stripping areas and producing tailings. These operations cause both positive and negative
impacts on the Benguela Current marine ecosystem, and are the source of conflict with
industries utilizing coincident resources.
To avoid these issues becoming a major political concern, and in keeping with the philosophy
of Integrated Environmental Management adopted worldwide, a three stage process has
generally been followed by the mining industry. Firstly, issues or impacts of major concern
to the public, government authorities and conservation bodies are identified during scoping
studies. Secondly, specialist or review studies are commissioned and the scale and extent of
impacts resulting from the mining activities examined through strategic environmental impact
assessments. Finally, in situations where the scale or intensity of the impact is considered to
be significant, mitigation measures designed to minimize negative and maximize positive
impacts on the environment are recommended. Collectively, this process leads to an
Environmental Management Programme (or Plan), which is a dynamic set of documents
updated as new mining techniques are employed and/or new information becomes available.
Most of the larger diamond mining companies and many of the smaller operators already
have, or are in the process of drawing up Environmental Management Plans.
The major issues that have been identified in the compilation of EMPs, and a summary of the
pertinent research undertaken and mitigation measures adopted by the industry are outlined in
this section and are summarized in Table 4.
6.2 Socio-economic Environment Positive Impacts
6.2.1 Creation of Revenue and Employment
South Africa
South Africa has 66 registered diamond mining concerns (excluding about 1500 registered
alluvial diggers), 49 of which produced rough diamonds in 1996 and 18 of which were from
marine concessions. Production statistics (Source: Diamond Enquiry) for the last 10 years for
South Africa as a whole indicate a fairly stable, but slightly increasing, level of annual
diamond production at around 10 million carats. Diamond production from kimberlite
sources has remained constant, accounting for 89% of diamond production, but there has been
a shift over the last 4 years from alluvial to marine diamond production. Alluvial diamond
production declined by 245 000 carats on average between the period 1987-1993 and the
period 1994-1997, but increased in 1997 due to higher output at De Beers Namaqualand
(DBNM) and some Trans Hex mines. In contrast, with the onset of deep-sea mining in 1991,
annual average carat production for marine mining increased from 53 885 for the period
1987-1990 to an average of 147 833 for 1991-1993. Marine diamond production statistics
show a decline since 1994, and particularly in 1995, as a result of reduced output from
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Alexkor's beach and marine sources. Marine mining at present contributes about 10% of
South Africa's total diamond production.
Diamond revenues, levied through income tax on diamonds, mining leases, mining rights and
diamond export duties, are put into the Central Revenue Fund from where they are allocated
to various budgets by the Government. The proportional contribution of diamond revenues to
overall tax revenue collections has declined over the last 17 years, and the diamond taxation
system is under review by the Katz Commission.
Statistics for diamond mining in 1997 indicated that 473 male employees worked at sea,
compared to a total diamond mining workforce of about 10 000 males and 900 females
(Minerals Bureau 1997 statistics), providing roughly 54% to the Gross Geographic Product
(down from 80% in the 1970s) and 66% of employment in the Namaqualand region.
Quantifying financial input into local economies from diamond mining is very difficult as a
result of the wide range of multiplier effects. Combined male and female earnings for all
diamond mining in 1997 totalled almost R553.5 million, however, it is unclear what
proportion of this may have entered the local economy since many of the higher income
employees live outside the region.
Namibia
As in South Africa, Namibian onshore diamond mining is winding down and the future lies in
offshore diamond mining. In 1996, beach and marine mining yielded 43% of total diamond
production (compared to 10% in South Africa), estimated at 1.49 million carats. The
diamond mining contribution to GDP was valued at N$2.1 million in 1997. As in South
Africa, diamond mining revenues go to Namibia's central government funds.
Namdeb is the biggest taxpayer, exporter and private sector employer in Namibia. To prolong
the life of its onshore activities, Namdeb invested in new dredge mining techniques in 1997
that led to increased production levels. Namdeb produces approximately 1.3 million carats of
which its deep-water operator, De Beers Marine, contributes 35%. In contrast, ODM
produced just over 58 000 carats in Namibia in 1997.
In 1993, 4500 workers (1% of Namibia's workforce) were employed by Namdeb at its
diamond mines in the Sperrgebiet. The majority of low-skilled employees originate from the
northern regions of Namibia and send remittances to families back home. At rough estimate,
a minimum of 800 people is employed at sea excluding shore-based operations.
Angola
In 1971 Angola, through formal production channels, produced 2.4 million carats, although
production subsequently declined due to civil war and instability. The 1991 cease-fire led to
an influx of thousands of "garimpeiros" (illegal diamond miners) to diamond fields, which
has lead to widespread uncontrolled digging and smuggling. Estimates suggest that over 50%
of the Angolan Government total potential revenue from alluvial diamonds has been lost to
smugglers. In 1994 revised legislation was passed to provide order to the diamond industry,
and in particular to provide for greater security. The new law gives ENDIAMA, the state
mining company which has the sole rights for prospecting, mining and marketing of diamonds
in Angola, powers of negotiation to attract foreign investors in new mining ventures either in
joint ventures with ENDIAMA or as sole investors.
As a result, production has since increased to 3.7 million carats in 1996 contributing roughly
9% to Angola's GDP, with most production from onshore mining. Significant interest has
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been shown in Angola's diamond resources since they are known to be of particularly high
quality. De Beers and ODM both have agreements with ENDIAMA to mine onshore
diamonds. De Beers plans to spend $75 million on prospecting three prospects covering 63
000 km2 in Quela, Mavinga and Lunda Norte. De Beers has indicated its commitment to
ensuring the stability of the diamond mining industry in Angola by investing in a 12-storey
diamond sorting building in Luanda.
No authorised offshore prospecting and mining has been undertaken in Angola to date,
although companies, such as De Beers, have been negotiating for rights with the Angolan
Government for some years.
Table 2. Summary of total diamond production, contribution by marine and beach mining and
total contribution by diamond mining to GDP for South Africa, Namibia and Angola.
Total
diamond
Contribution from
Contribution to GDP
production (ct)
beach and marine
(U$D)
mining
South Africa
10 000 000
10%
7 300 000
Namibia
1 500 000
43%
350 000
Angola
3 700 000
0%
?
6.2.2 Human Resource Development and Social Betterment
South Africa
Initiatives to develop the skills of employees have been undertaken mainly by the large
onshore mining companies who employ a significant staff complement of mainly low-skilled
workers. Onshore human resource development initiatives by large companies include the
establishment of trusts to fund training; sponsorship of community needs (such as clinics);
conducting skills training at mining towns; and developing alternative land uses. Training on
mines has been fragmented, however, and qualifications are not nationally standardised,
leaving most employees with little improved chance of finding jobs.
DBCM, for instance, together with Anglo America, contribute to the Chairman's Fund, which
is the largest corporate contributor to educational and social development in South Africa. In
1997, the fund made donations totalling over R56 million of which De Beers contributed
R18.5 million. Most of the funding is invested in education.
To improve financial viability of mining, extend the life of the mines, and create jobs, some of
the larger companies are investigating, or are already undertaking, alternative land use
activities. Alexkor has mariculture and farming projects underway, and have further plans for
mariculture expansion. The company, in conjunction with the Northern Cape Government, is
also investigating tourism and other land use development options with a view to providing
up to 700 jobs (if all plans reach fruition). DBNM are awaiting approval to start abalone
cultivation and harvesting of Gracilaria and are considering other projects such as hemp
cultivation and other agricultural projects. It appears that mariculture ventures undertaken by
diamond mining companies in their processing dams would not otherwise be financially
viable and can be considered a positive spin-off. It is not known whether these ventures
would remain viable after mine closure, however. Unfortunately, the success of many of
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these projects will depend largely on the availability of fresh water - a scarce resource along
the Namaqualand coast.
Namibia
Namibia's Minerals Act, 1992, requires holders of any mineral licence to: give preference to
Namibian citizens with appropriate skills; carry out training programmes to promote the
development of Namibian citizens; make use of products, equipment and services produced
and available within Namibia, and co-operate with Namibians involved in the mining industry
to promote skills development.
Namdeb took initiatives with Namibian small contractors in 1990 after pressure was exerted
to expand shallow water operations in Namibia, similar to those that had been operating in
Namaqualand since the 1980s. However, many small contractors operating from the beach
south of Lüderitz failed to make a profit because of adverse working conditions and
operational problems. Larger-sized "small contractors" operating from boats (e.g. Yam
Diamonds) and others produced over 132 500 carats in 1994. Small contractors employ
roughly 250 people, most of whom live in Lüderitz.
In line with government policy and to prolong the life of the mine by reducing overhead costs,
Namdeb has privatised most non-mining activities in its mining town of Oranjemund, which
are now run mainly by black entrepreneurs. The diamond industry has also benefited the
local economy of Lüderitz (which houses its Elizabeth Bay mine) through the payment of
wages (estimated at N$8 million), local sponsorship and direct business (N$3 million).
6.3 Socio-economic Environment Negative Impacts
6.3.1 Shifting Emphasis from Onshore to Offshore Mining
The intensity of onshore diamond mining in the coastal zone is in decline with a shifting
emphasis to offshore operations. This is likely to have far reaching implication for aspects
such as employment and skills training in both South Africa and Namibia.
Impact on Employment: The number of employees in South Africa's onshore diamond
mining industry as a whole has declined from over 19 500 in 1992 to less than 15 000 in 1997
(a rate of approximately 2.5-3% per annum). Alexkor and DBNM have been scaling down
onshore operations and will continue to do so over the next 25 and 10 years respectively, as
diamond reserves are depleted. Between the two companies, a minimum of 1800 jobs has
been lost since 1992. The majority of employees in onshore diamond mines are from
Namaqualand, about 80% of which are low-skilled workers. Mine retrenchments will
therefore exacerbate the already dire unemployment situation in Namaqualand unless
alternative employment sources are found. The unemployment rate in rural areas of
Namaqualand has been estimated at 60% - a problem that has been compounded by the
decline of the fishing industry, particularly the rock lobster industry.
Loss of jobs due to downscaling is not restricted to South Africa. Downscaling through
natural attrition, facilitated by retirement and voluntary retrenchments, is ongoing in Namibia,
and will continue over the next two decades exacerbating the already high unemployment rate
in this region (estimated at about 34%).
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The decline in onshore mining has occurred in parallel with a rapid growth in marine mining.
Onshore mining companies are shifting the focus of their activities towards marine mining,
and other companies have entered the diamond mining industry (e.g. Ocean Diamond Mining,
Nautical Diamonds, BENCO). Marine mining is a highly specialised activity, requiring high
capital inputs in the form of purchasing, maintaining and equipping mining vessels with
technical processing equipment. Relative to onshore mining, marine diamond mining
requires lower inputs of low-skilled labour - up to 10% (in contrast to the 80% in onshore
mines). With the present lack of alternative job sources in Namaqualand, the majority of
workers retrenched from onshore mines in the next decade have little chance of finding work
in the offshore industry. Furthermore, because a high level of skills are required for offshore
mining, the majority of staff is recruited from urban centres overseas and in South Africa,
particularly impacting Namibian employment. DeBeers Marine, for instance, employs
qualified British Marine Officers because of the lack of qualified South Africans or
Namibians. This is set to increase, as more mining vessels become operational DeBeers
Marine, ODM and Namco are all planning to augment their mining fleets by one vessel in the
next two years.
In the absence of alternative employment in Namaqualand, many retrenched workers will, in
all probability, relocate southwards to Cape Town or Saldanha (the centre of the West Coast
Investment Initiative), attracted by the prospect of industrial expansion and job creation. For
those that remain in Namaqualand, the loss of jobs and financial hardship that this will create
may cause greater dependence on the natural resource base. This may include increased
pastoralism and resultant overgrazing of sensitive coastal vegetation as well as increased
collection (largely through poaching) of coastal shellfish resources (abalone, mussels and rock
lobster).
Impact on Skills Training: With continued job losses due to downscaling of onshore mining
activities, fewer training and skills enhancement opportunities will be available for unskilled
workers thereby compounding the unemployment and poverty problem in rural mining areas.
Migration of workseekers to other urban centres is likely to erode the economic support base
of the former and compounds the unemployment problem in the latter. Offshore mining also
provides fewer training opportunities for low-skilled employees, limited mainly to
sponsorship of students to study engineering-related courses.
Mitigation: There is no direct mitigation that can be undertaken to stem the loss of jobs resulting from
declining coastal reserves. Investment in training and investigation of future landuse options, however,
are indirect means to provide opportunities for self-help.
Onshore and offshore mining companies are implementing training programmes that target upgrading of
skills which will improve the chances of employees obtaining secure jobs in the post-mining
environment. These companies should allocate a certain proportion of annual turnover to training and
sponsorship for education. In line with the new Minerals Policy and Mine Health and Safety Act, which
gives employees the right to education and training, the South African government has undertaken to
promote Adult Basic Education and Training (ABET), and in particular, to ensure that people in the
minerals and mining industry have access to quality education and training. The South African
Qualifications Authority Act is also working towards standardising, at a national level, the qualifications
achieved by training on mines.
6.3.2 Involvement of Small Scale Miners
Impact: Limited involvement of small-scale miners in the diamond mining industry has created
imbalances in the distribution of benefits of mining and has restricted the potential for these miners to
secure a living. Small-scale mining has been hampered by factors including: 1) lack of access to finance
by financiers unwilling to fund ventures which offer limited financial security and returns; 2) lack of
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appropriate structures to assist small scale mining development; 3) location of mining operations far
from major markets; 4) lack of access to marketing channels; 5) lack of management and technical skills,
and; 6) inability of small-scale entrepreneurs to provide adequate diamond security measures. Not only
have these problems marginalised small-scale miners, but they have also led to the non-exploitation of
marginal diamond deposits regarded by larger companies as unprofitable.
Mitigation: In line with the new Minerals Policy of South Africa and policies of the Ministry
of Mines and Energy of Namibia, the respective governments have pledged to increase
participation in the mining industry by those previously excluded. Measures that have been
proposed to improve small miner involvement in the mining industry are: 1) to facilitate
access to funding through appropriate institutions; 2) to ensure that information on technology
and mineral development and exploitation is made available to the small-scale mining sector;
3) to encourage municipalities to support the emergence and development of small-scale
miners, and; 4) to enhance the capacity of Department of Minerals and Energy to provide
support to small-scale miners.
6.3.3 Promotion of Joint Management Ventures with Employees
Impact: Racial imbalances are prevalent within the mining industry (as in other industries)
with the majority of middle and senior management positions still occupied by whites. Lack
of joint management ventures or partnerships with mine employees has led to lack of
advancement of "black" workers and professionals into senior positions or management
levels. This has created a situation whereby black employees have become demoralised
through lack of economic empowerment, which undermines the political and economic
stability of the mining industry.
Mitigation: Training programmes to upgrade skills amongst the workforce have targeted this
disparity (see above) but will still take many years to effect significant changes. To date, few
mining companies have sought to involve employees in joint management ventures such as
shareholder participation schemes. The policies of South Africa and Namibia (see above)
seek to improve employee-employer relations within the workplace and promote black
participation in ownership and management within the mining industry. Authorities have also
undertaken to consider changes to tax administration and company law to reduce obstacles to
mining companies introducing Employee Share Ownership Participation Schemes for low-
income workers.
6.3.4 Reduced Revenue from Offshore Diamond Mining to Local Areas
Impact: Onshore mining companies have devolved significant benefits to local areas. Most large
companies have, or are in the process of, compiling and implementing company policy for the purchase
of local goods and services and, where possible, from entrepreneurs from previously disadvantaged
communities. In this way, these mining companies seek to devolve mining benefits to the local area and
in so doing create a stable economic and political environment within which to conduct their activities.
Opportunities, however, for offshore mining companies to do likewise are limited by the fact that
operations are conducted out of major urban centres, and most goods and services required to support
offshore mining are high tech and not available from small scale enterprises. This is particularly the case
in Namibia, where the use of Cape Town as a base for vessel servicing, repairs and victualling represents
a loss of potential income for the Namibian economy. The shifting emphasis from onshore to offshore
mining will lead to further losses to local economies.
Mitigation: No active mitigation measures have been implemented.
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6.3.5 Allocation of Diamond Mining Revenues to Mining Areas
Impact: The diamond mining industry and the governments of South Africa and Namibia
have been criticised by communities and local authorities for the lack of investment in
infrastructure and services in towns near diamond mining areas. This stems from the policy
where diamond revenues are put into a central revenue fund that are allocated to various
budgets by the Government, rather than direct re-investment in the local district. To date,
initiatives to address the allocation of a portion of these revenues to local and/or provincial
authorities have been rejected. The mining industry, as well as the fishing industry, has not
been required to directly fund the maintenance of state or provincial roads and have placed
strain on harbour facilities. This is a contentious issue amongst relevant local authorities.
Despite the high income realised by diamond mining, areas surrounding diamond-mining
exhibit retarded growth, lack of investment and in some places (e.g. Lüderitz) a growing
population of unskilled workseekers. Elsewhere, where onshore diamond mining is in decline
(e.g. Namaqualand), towns exhibit outmigration of the economically active age group to seek
work elsewhere because of the lack of economic investment. Work seekers tend to move
towards urban areas, such as Cape Town and Lüderitz, thereby compounding problems of
crime, poverty, family separation and general demoralisation when jobs are not found.
Mitigation: No active mitigation measures have been implemented.
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6.3.6 Strain on Infrastructure and Services of Towns near Mining Areas
Impact: Several towns along the South African and Namibian coasts are experiencing problems arising
from the demand for infrastructure, services and resources to support the diamond mining industry.
Many towns do not have the capacity to support the growing offshore mining industry a problem
compounded by the lack of direct financial inputs by Government. Infrastructure, services and resources
which are often over-stretched include strain on harbour facilities, land fill sites, fresh water, and
accommodation.
Mitigation: Facilities and the capacity of affected towns to support mining are being upgraded through
redirection of financial and service inputs by Government and/or by creating incentives for mining
companies to do so by working in conjunction with local authorities. This process needs to be expedited,
however.
6.3.7 Conflict with the Fishing Industry
Issue: Conflict exists between the rock lobster fishing and marine diamond mining industries.
The rock lobster industry holds the diamond mining industry responsible for the killing of
lobster and large-scale destruction of lobster habitat by stirring up sediments, cutting kelp,
and poaching. Although research studies suggest there is no causal relationship between
increased marine diamond mining and the decline in fish catch rates experienced in recent
years, the issue remains a source of conflict between the two industries.
Mitigation: The formation of fora or committees on which all the major stakeholders are
represented appears to be the current trend for pre-empting and resolving conflicts as they
arise. The Marenpro Forum in Lüderitz, Namibia, in which representatives of the fishing and
mining industry as well as government ministries participate, is one such active forum. A
West Coast Liaison Committee is soon to be established and has similar objective to the
Marenpro Forum. All the players in the diamond mining industry in each area along the coast
e.g. Western Cape and Northern Cape and Namibia should be encouraged to participate and
contribute to these fora.
6.3.8 Impacts on Future Land Use and Tourism
Impact: Perhaps one of the most significant impacts of onshore and surf zone mining is the
impact on future land use and tourism potential. Trenches, mining blocks, overburden dumps
and an overabundance of roads scar the landscape, considerably altering the original
topography. This constitute a significant aesthetic impact, which will have "knock on" effects
on the tourist industry and may jeopardise the future land use potential of decommissioned
mining land.
Mitigation: Currently, the issuance of mining licences requires proof of funds for
rehabilitation. However, prior to 1980 rehabilitation was not enforced, and large areas have
been left scarred and un-rehabilitated. Some of the damage was caused by companies who no
longer operate and the present holders of mining licences for these areas cannot be held
responsible. The ultimate responsibility for rehabilitating these areas now lies with the
government of the respective countries. In South Africa, the Department of Mines and
Energy (DME) and the Department of Water Affairs (DWAF) contribute to a fund for derelict
and ownerless mines, which is used for rehabilitation, and health and safety reparations.
However, limited funding as well as the inherent problems of rehabilitation in arid areas, are
the biggest constraints to successful rehabilitation.
6.3.9 Loss of Cultural Resources
Impact: The entire southern African coastal zone has a wealth of archaeological deposits,
mainly found as surface shell middens, to a lesser extent cave deposits, and shipwrecks.
Onshore, poorly planned access roads, camps and processing areas can inadvertently destroy
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middens constituting a significant loss to cultural heritage. Within the surf zone, shipwrecks
are particularly vulnerable to mining disturbance. At least 2000 vessels are known to have
sunk or run aground off South Africa's shores since 1500 of which only a small fraction have
been located. Surf zone mining, through displacement of obstacles such as boulders and
suctioning of gravel, risks dispersing and breaking up shipwreck material. At present, the
extent of damage to archaeological deposits has not been quantified.
Mitigation: Historically, mining companies have not had a responsible attitude towards
protection of cultural resources. This is probably due mainly to the freedom the mining
industry has enjoyed as South Africa's and Namibia's most important economic sector and
the lack of environmental controls exerted on the industry until recently. In South Africa,
negligence towards cultural resources has been partially encouraged by legislation that
excludes diamond mining from the regulations under the Environmental Conservation Act on
the use of off-road vehicles, and to portions of the National Monuments Act. This situation is
changing, especially amongst the larger mining companies, who are demonstrating greater
environmental responsibility in this regard by commissioning archaeological surveys prior to
expanding their mining activities. Some companies, however, still have far to go in this
regard.
6.4 Biophysical Environment - Positive Impacts
6.4.1 Conservation of Flora and Fauna in Restricted Areas
Impact: The most notable positive impact on the biophysical environment comes from the de
facto nature reserve status of much of the terrestrial mining area. Access to most mining areas
is highly restricted in order to minimise diamond theft, and as a consequence, human
interference in many areas has been kept to a minimum. Many habitats have been left in
pristine or near pristine condition, the scale of which is not insignificant - the Namibian
`Sperrgebiet,' for example, alone encompasses some 26 000 km2 of land.
The positive benefits from diamond mining are unequally shared between the marine and
terrestrial environments, however. While access is restricted on land, large-scale offshore
fishing enterprises continue uninterrupted along much of the diamond coast. Only shore-
based forms of exploitation are effectively excluded.
6.5 Biophysical Environment - Negative Impacts
Considered as a whole, marine diamond mining affects only a small fraction of the marine
environment (Table 3). The overall aerial extent of mining activities encompasses less than
1% of the concession areas in South Africa and Namibia per annum, irrespective of the form
of mining category. On the scale of the BCLME therefore, impacts of diamond mining are
deemed to be of low to negligible significance. At local scales, however, their impact may be
more severe. Due consideration must be given to the scale of operations when the impacts
outlined below are evaluated.
Table 3. Relative extent of the various diamond mining activities in South Africa and
Namibia.
Type of Mining
% of Concession Mined per Annum
Beach Mining
<0.5 %
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Shallow-water Mining Shore Based
<0.001 %
Shallow-water Mining Boat-based
<0.01 %
Mid-water Mining
<0.5 %
Deep-water Mining
<0.01 %
6.5.1 Environmental Impacts of Terrestrial Mining
Mining, Overburden and Tailing Dumps and Roads
Impact: The impacts of terrestrial mining are caused individually or in synergy from 10
categories of mining activity: prospecting trenches; overburden dumps; tailings dumps;
mining blocks; sediment plumes; roads and vehicle tracks; scarring and quarries; mining
infrastructure; seaward disposal of fines tailings; and beach mining. Perhaps the three
greatest impacts from terrestrial mining are due to the removal of overburden and
diamondiferous gravel, the creation of overburden and tailings dumps, and the construction of
roads. These activities impact soils and plant communities, in turn impacting the animal
communities associated with them. The degree of impact depends on both the scale of the
mining activity and the type of soil that is impacted. Actively forming soils harbour plant
communities that are dynamic and resilient to even massive disturbances, whereas plant
communities growing on older complex soils are dependent on the equilibrium of the soil, and
usually fail to recover from disturbance if this equilibrium is not maintained. Stripping of
overburden with a complex topsoil therefore has a relatively greater impact of longer duration
than stripping an area of actively forming soils. Although some areas are back-filled, topsoils
are generally not stored and the loss of topsoil means that recovery of plant comminutes to
their former state depends on the formation of new soils in the order of decades to centuries.
Loss and recovery of animal fauna presumably follows the same route. Roads and heavy
vehicle movement has the opposite effect to mining. These activities tend to compact the soil,
thus rendering the area unsuitable for re-colonization by new plants. Additionally, it should
be noted that numerous rare, threatened or endemic animal and plant species occur in the
diamond areas, and are negatively affected by mining activities.
Areas denuded of vegetation, such as trenches, mining blocks and tailings are inherently
unstable, with the result that sand plumes frequently develop due to the strong winds and flat
topography characteristic of the mining area. These sand plumes can be quite extensive,
smothering vegetation and causing a significant secondary impact. It is believed that
sediment plumes may have been a triggering force in the collapse of the saltmarsh ecosystems
of the Orange River wetlands.
Additional, lesser impacts are caused by mining infrastructure as buildings and equipment are
often left on site following completion of mining, or if the equipment becomes derelict. Not
only does this hinder recovery of the ecosystem, it also causes an aesthetic impact, in addition
to the mine dumps and trenches that now dominate in a previously flat landscape.
Mitigation: Mitigation is principally through rehabilitation of the affected areas. The severe
disturbance that results from mining in these arid terrestrial ecosystems, the dynamics of
which are greatly retarded by the harsh environment, makes rehabilitation very difficult,
however. Generally larger mining companies make the effort to stockpile topsoil and
overburden separately and replace this material in appropriate positions in the refilled mining
blocks. Little or no effort is made to rehabilitate prospecting trenches, however.
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Seaward Disposal of Fine Tailings
Impact: Discharging fine tailings to sea impacts the intertidal region, whether at a large scale
such as the Elizabeth Bay Mine (Namibia) or at a smaller scale such as small contractors
operating from the shore.
The sediment plume generated from the seaward disposal of fine tailings impacts intertidal
rocky shores. The impact is localised to the extent of the sediment plume a scale of 100 m
in the case of large recovery plants, and a scale of 10 m for the smaller operations. The
impact is caused by sand inundation that appears to impact particularly the grazers in the
intertidal zone (e.g. Patella granatina, P. argenvillei), causing a decrease in the ability of
these animals to adhere to the substrate. The resultant reduction in herbivory often leads to an
increase in foliose algal cover, which causes shading and in turn decreases corralline algae
cover below. A cascade effect is the loss of food to seabirds that forage on the intertidal. At
small-scale contractor mining sites, full recovery takes less than two years after the cessation
of mining activity.
Subtidal rocky shores do not appear to be adversely affected by light siltation by mine
tailings, with the possible exception of sponges which are particularly sensitive to sand
inundation. Should a beach prograde to cover the reef however, complete loss of habitat with
the associated communities, will ensue.
The seaward pumping of fine tailings on sandy shores can have a profound effect on
communities associated with these habitats. Fine fractions of tailings are suspended in the sea
and advected offshore, whereas coarser fractions settle rapidly onto the beach. If large
volumes of tailings are pumped seaward, this can lead to severe alterations of the physical
state of the affected beach. For example, fine tailings at Elizabeth Bay have increased the size
composition of sand across the entire beach. Prior to mining, Elizabeth Bay beach was
composed of fine to very fine sands, with sand particles coarser than 100µm making up less
than 10% of the total amount. With the advent of mining in 1991, mean particle size at the
centre of the beach where tailings are disposed has increased from 110-160 µm to 600-900
µm, with a accompanying reduction of surf zone width by ~50% and an increase in the beach
slope from 1:40 to 1:14. Beach macrofauna communities are almost entirely determined by
the physical state of the beach, and this alteration to the physical state of the beach has led to a
shift from a mussel dominated community to a community dominated by crustaceans with an
accompanying loss of diversity. Following mine closure, recovery of the affected beaches to
a pristine state will depend on the speed at which the beach returns to pre-mining physical
conditions. This could take decades or even centuries.
Fish appear to benefit from the turbidity plume produced by the discharge of tailings spoil
material from the Elizabeth Bay diamond mine, with increased species richness and
abundance recorded within the plume relative to control sites on the same beach. It is
believed that this is attributable to increased shelter from predators provided by the plume.
Loss of potential food items (beach macrofauna discussed above), reduction of habitat
through the narrowing of the surf zone, and the development of more turbulent waters
associated with a narrower surf zone must have some, though unquantified, negative effects.
Mitigation: Terrestrial slime dumps are an alternative to the seaward disposal of tailings, but
this option is not without its own impact on the environment. No other mitigation or
rehabilitation options are considered economically feasible.
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6.5.2 Environmental Impacts of Beach Mining
Seawalls
Impact: The construction of seawalls has significant effects on the marine environment.
Seawalls are constructed to push the shoreline between 200 and 500m into the sea, permitting
access to diamond deposits of the subtidal. The seawalls require constant maintenance as
rough seas typical of this coast continually erode the walls. Overburden alone is often
insufficient for the construction and maintenance of these dams, and as a result, other sources
of material are used for building material including the coastal dunes (in itself an impact on
the terrestrial environment). Following mining, maintenance of the seawalls ceases, the wall
collapses, and the area is left to reform a new shoreline. Because the seawalls are constructed
of a melee of fine sands to boulders not resembling the original beach material, the resulting
shore is left physically altered. In some cases fine-grained beaches have been left as coarse-
grained beaches while in other cases, rocky reefs have been converted to boulder fields. As
discussed above, alterations to grain size can have profound effects on biological communities
of sandy beach and rocky shore communities. Although such an impact has hitherto not been
assessed in terms of field studies, the effects are roughly predictable. Pre-mining baseline
data has been collected at one site, however, and the impact should be fully quantified once
mining is underway in the next few years.
Mitigation: Mitigation action includes the use of materials for seawall construction that are
roughly equivalent to the sandy beaches that are stripped.
6.5.3 Environmental Impacts of Shallow-Water Mining Operations (<30m depth)
Diver-assisted shallow-water mining activity targets gravel-filled gullies and potholes
between reef ridges. Access to this gravel is either via the shore or through boat-based
operations.
Access to Shore-based Mining Sites
Impact: Access to nearshore diamondiferous gravel by shore-based operators often requires
the construction of new roads, blasting rock cuts, moving of boulders and the construction of
work camps in order to move machinery sufficiently close to the seashore. The act of mining
leaves tailing dumps, most often left above the high water mark. The aesthetic and terrestrial
impacts of these activities, albeit at a larger scale, have been discussed above.
Mitigation: It has been suggested that impacts of this nature could be mitigated if nearshore
diamond pumping were undertaken exclusively from boats. Although possible, start-up costs
associated with such a policy may be prohibitive for new entrants.
Kelp Cutting
Impact: Kelp (primarily Laminaria spp.) is often cut by divers to provide unencumbered
access to the mining site. This activity causes a localised impact, the severity and duration of
which depends on the extent and frequency of kelp cutting and the age of the plants. Kelp
sporelings settle most successfully at or near the holdfasts of adult kelp plants, and recovery
of kelp beds proceeds from the fringe of the cut area. Therefore, the greater the area cut the
slower the recovery. By the same argument, a clear-cut area or repeatedly cut area will
recover relatively more slowly than an area where only adults are cut and small kelp plants
are left behind. In the best case scenario, recovery can take less than two years, although in
some areas recovery has not occurred, especially where high densities of sea urchins
(Parechinus angulosus) occur. Sea urchins feed preferentially on kelp sporelings, and in
sufficient densities can keep an area entirely denuded of kelp. Many animals utilise the kelp
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bed habitats during the juvenile stage of their lives, and the loss of this habitat could have a
small but important cascade effect.
Mitigation: Mitigation action includes restricting the width of the lane of kelp cut,
discouraging clear-cutting, and discouraging repeated cutting.
Benthic Communities
Impact/Mitigation: Nearshore pumping of diamondiferous gravel by divers has a myriad of
effects, such as the development of sediment plumes; uncovering of new reef where gravel is
removed; the smothering of reef where tailings are discharged; the de-stabilising of reef where
`cementing' gravel is removed; physical disturbance of the suction pipe and diver abrading
the reef; and the moving of boulders to access gravel beneath.
Concern has been expressed regarding the effect of sediment plumes on the primary
productivity of phytoplankton and macroalgae. Compared with the naturally high levels of
suspended sediment in this highly dynamic nearshore environment or the fine tailings
deposited into the sea from land-based mining operations, this impact is thought to be
negligible.
Nearshore mining putatively impacts the habitat of rock lobsters, rock lobsters themselves and
their food source. A strong association of rock lobsters with reef- and boulder-dominated
seabed has been established, as has the diversity of benthic organisms, most of which
constitute the food source of the rock lobster. Diamond mining primarily targets sand and
gravel areas, however, and the mining process does not directly threaten the reef and boulder
communities. By removing gravel, mining may in fact expose expanses of previously
embedded rock and boulders. Although these are initially uninhabited, recolonisation by
benthic communities is rapid and the area becomes statistically indistinguishable from
unmined areas within six months, despite the bottom topography being considerably altered.
Mining activity therefore can effectively convert gravel gullies into boulder beds, which are
potentially suitable for habitation by rock lobsters.
The converse can also occur, however, if tailings are dumped onto reef- and boulder-
dominated seabed, thereby smothering rock lobster habitat and/or food. Some dumping
inevitably occurs on adjacent reef, but if this is restricted the impact is thought to be limited,
as small quantities of tailings will be dispersed during subsequent storms. If the impact is
cumulative, however, this can have the effect of converting preferred rock lobster habitat into
sub-optimal small boulder or unsuitable gravel areas. These areas may be stabilised in time,
although further research is needed before conclusive answers can be given concerning the
impact of rock piles and tailings dumps. Mitigation measures should, however, include
keeping the shifting of boulders to a minimum and dumping of tailings further offshore on
non-reef areas.
Although diamond divers admit to pumping rock lobsters `for the pot', the quantities involved
are insignificant compared to the annual quota landed by the commercial rock lobster
industry. To discourage poaching, however, mining vessels should be inspected occasionally
for illegal catches, and mining licenses be confiscated if found guilty.
Seabirds and Seals
Impact/Mitigation: Disturbance of seabirds and seals on the nearshore islands off the
Namibian coast is a further issue of environmental concern. Nearshore subcontractors
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working the island concessions are forbidden to land on the islands except in emergency or if
accompanied by personnel from the Ministry of Fisheries and Marine Resources (MFMR) in
Lüderitz. All landings are recorded and reported to the MFMR.
Harder Fishing
Impact/Mitigation: Allegations have also been made that the activity of diamond boats within
the Olifants River estuary, and mining operations near the estuary mouth, have led to a
reduction in gillnet catches of harders by local subsistence fishermen. Problems associated
with waste disposal and maintenance operations which potentially release contaminants (e.g.
oil, antifouling paints, sewage) into the estuarine environment have also raised concerns.
Although the conclusions of the EIA were speculative only, reduced catches were attributed
to overfishing and possible recruitment failure rather than boat traffic. It was, however,
recommended that mining near or within the mouth and increased use of the estuary as a
harbour for diamond vessels be discouraged.
6.5.4 Environmental Impacts of Mid-water and Deep-water Mining Operations
(>30m)
Tailings Plumes
Impact: Fine tailings can remain in suspension for long periods forming plumes that are
advected away from the mining vessel by ambient currents. Most of the silt sinks rapidly
(minutes) during the initial convective descent phase; entrainment of seawater resulting in
dilution of both the dissolved and particulate constituents of the discharge. Ultimately the
density of the diluted discharge becomes neutrally buoyant, with the remaining particulate
matter spreading and settling further through passive diffusion (hours). The potential impacts
on water column processes of the temporary redistribution of slow sinking silts and clays
originating from mining activities has received much attention in both Namibia and South
Africa. A structured approach to the assessment of suspended sediment plumes, as
recommended by the Environmental Protection Agency of the United States, has been
adopted by the mining companies concerned. This includes desktop studies and predictive
modeling in the pre-mining phase, followed by more intensive in situ biological and
toxicological evaluations requiring field sampling, laboratory testing and rigorous data
analysis.
Although the plumes may extend several kilometers, the potential impact on phytoplankton
communities through reduction of light, nutrient enrichment, remobilization of contaminants,
and deep oxygen consumption through decomposition of silt particles during descent, is
generally very limited and localized. The extent of the impact of the plume depends largely on
the proportions of silts and clays in the targeted sediment, and the sea surface conditions
during disposal. Measurements of dissolved nutrient concentrations (NH4, PO4, NO3 and
NO2) in the tailings discharge were within the specified limits set by the "Water Quality
Guidelines for the South African Coastal Zone". Rapid descent and dilution of dissolved
nutrients and contaminants in the convective descent and passive dispersion phases resulted in
ammonium concentrations declining to below detection levels within an hour of release.
There was no evidence of the release of NO3 and NO2 from interstitial waters as is to be
expected from anoxic sediments. Due to their low solubility in seawater, elevated
concentrations of trace elements (Cd, Co, Cr, Mn and Pb) have, however, been recorded in the
tailings plumes; those of Cd, Cr, Cu and Zn breaching the recommended water quality
guidelines. Evidence suggests that pesticide levels resulting from resuspended biogenic muds
are unlikely to exceed recommended guideline levels. Remobilization and subsequent uptake
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of contaminants by marine organisms has important implications for bioaccumulation down
the food chain. Assessments of the potential oxygen consumption through decomposition of
silt particles during descent have indicated that rates are low and no measurable impacts on
the typical bottom water concentrations are expected.
Ferrosilicon loss in the tailings has been reduced through the introduction of vertical impact
crushers and sophisticated recovery systems, but an average of 127 t (in 1995) per vessel are
still lost annually. In areas with iron deficiency, this could potentially increase primary
productivity and alter the phytoplankton community structure.
Mitigation: No mitigation is warranted.
Impacts on Benthic Fauna
Impact: The mining process removes unconsolidated sediments, resulting in the destruction
of benthic fauna, and modification of the benthic habitat in the mining path and in adjacent
areas where disturbed sediments are re-deposited. This causes direct mortality of organisms
through the dredging and discharging process, potential smothering of organisms affected by
the fallout, and possible aggravation of oligoxic conditions causing migration or even death.
Consequently, a significant change in abundance and diversity of benthos has been observed
in mined areas and their immediate vicinity. Substantial restratification of sediments occurs
thereby influencing the rate of recolonisation as well as the structure of the developing
benthic community. The recovery rate of a perturbed area has been estimated to take as long
as eight years, but habitat modifications may be permanent resulting in a persistent
environmental impact and change in the associated communities. This may potentially affect
the food chain and have important implications for the distribution and abundance of other
marine organisms such as rock lobsters and fish. However, without baseline data on the
natural variability and patchiness in benthic community structure with sediment type, depth,
and transient changes in water quality, it has not been possible to provide a cumulative
assessment of mining damage. Furthermore, spatial heterogeneity of benthic communities
has precluded the application of results across wider areas.
Mitigation: Leaving lanes of sediments undisturbed will facilitate the recovery of benthic
communities.
Impacts on Fish and Fisheries
The fish fauna of the west coast of South Africa and Namibia has a low diversity and contains
few endemic species. Most species are widespread and to some extent migratory and are thus
able to escape from oligoxic incursions as well as disturbance by mining tools. Although
baseline knowledge exists of the abundance and distribution of the commercially important
species in the areas of mining activity (hake, monkfish, sole, kingklip, and rock lobster),
attempts to quantify these on a sufficiently fine scale to determine the impacts of offshore
mining have not been attempted. Rock lobster and sole are the most restricted in their
distributions and migratory capacity and thus the most likely to be at risk. The main
spawning areas of the commercially important fish species are primarily north (<25°S) of
current mining activities in Namibia, and south (St Helena Bay) of activities in South Africa.
The shallow shelf region between St Helena Bay and the Olifants River appears to be utilized
as recruitment grounds by most of these species. Desktop studies have identified the main
potential impact of mining on fish to be on the breeding success rather than on the adult
stocks themselves. The impact is thought to be greatest in the water column below the
thermocline where the vulnerable early life-history stages may be negatively influenced by
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oligoxic conditions in the suspended sediment plumes. No quantitative data are available,
however, and the coincidence between the sediment plume and fish egg and larval
distributions needs to be investigated further.
The principle risk of offshore mining activities to rock lobster is the aggravation of oxygen
poor conditions and the disruption of seasonal offshore migrations as part of their breeding
and moulting cycles. Most of the rock lobster fishing activities occur within 5 nautical miles
of the coast; overlap with offshore mining is thus limited. However, information on rock
lobster behaviour in deeper water and the role of migrations is lacking and should be
researched further before conclusions concerning the impact of mining can be made.
Impacts on Other Marine Fauna
The primary sources of noise associated with mining operations are the sounds caused by
equipment and machinery, and sonar and seismic equipment. The latter frequencies overlap
with the spectrum of frequencies used by marine mammals to communicate and have the
potential to cause injury and discomfort.
Some crew changes involve aircraft flying low over wetlands, which has been found to cause
disruption to the waterbirds. Reactions to fixed-wing aircraft and helicopters varies between
bird species but foraging, roosting and breeding activities are generally negatively affected,
potentially reducing reproductive success. Although no similar studies have been conducted
on the effects of low flying helicopters on seabird and seal populations on offshore islands,
short-term disturbances are to be expected.
6.5.5 Generic Impacts
Numerous impacts are generic in nature, synonymous with virtually any shipping activity.
These include waste disposal, sewage, paints, hydrocarbons, bunkering, freshwater, etc.
Legislation is in place to deal with many of these impacts, and consequently these are not
dealt with here.
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Table 4. Summary of Socio-economic and biophysical impacts of marine diamond mining operations in the BCLME.
Socio-Economics:
Positive Aspects
Impact
Creation of Employment and
· Marine diamond mining industry provides considerable employment
Revenue
and tax revenue in RSA and Namibia.
Human resource development
· Some of the larger companies diamond companies in RSA and
and social betterment
Namibia have started programs to develop skills and improve living
conditions for low skilled workers (e.g. trust funds for training,
sponsorship of community needs, development of alternative land
uses).
· Namibian companies are required to preferentially employ Namibian
citizens and purchase Namibian goods and services. Some
companies have taken initiatives with small contractors to expand
shallow water operations.
Socio-Economics:
Negative aspects
Impact
Mitigation
Shifting emphasis from
· An ongoing shift in emphasis from onshore to offshore mining is
· Alternative land-use options and training
Onshore to Offshore Mining
leading to escalating unemployment in coastal towns in RSA and
initiatives are being promoted and/or
Namibia because of reduced low-skilled labour requirements.
investigated.
· Revenue from offshore mining reaching local areas is much reduced
compared with onshore mining as the larger vessels are supplied and
serviced from a few large urban centres (e.g. Cape Town and
Lüderitz).
Involvement of small scale
· Opportunities for involvement of small scale miners in the diamond
· Mechanisms are being introduced to
miners
industry has been very limited owing to limited access to finance,
facilitate entry by small-scale miners
technical skills and poor security.
(e.g. improved access to funding and
technology).
Allocation of mining revenue
· Tax revenue from mining concerns in RSA and Namibia is generally · Financial and service inputs are being
to mining areas
fed into a central revenue fund and is not necessarily re-invested in
redirected by government and industry
local districts. This has resulted in diamond mining areas exhibiting
to upgrade facilities and capacities of
retarded growth and poor infrastructure.
affected towns.
Conflict with the fishing
· Animosity exists between rock lobster fishermen in RSA and
· Fora and committees are being
industry
Namibia, and the diamond mining industry whom they hold
established in RSA and Namibia to
responsible for declining catches.
resolve conflicts between major
stakeholders.
Foreclosure on future land use · Mining activities tend to scar the landscape and can potentially
· Laws in RSA and Namibia now require
options
impact future land use options long after mining ceases (e.g.
the rehabilitation of terrestrial mining
tourism).
areas.
Loss of cultural resources
· Mining operations have the potential to disturb both terrestrial and
· Archaeological surveys are now
marine archaeological sites including shell middens and ship wrecks.
generally commissioned before new
areas are mined.
Biophysical Environment:
Positive Aspects
Impact
Defacto reserve status of
· Access to mining areas is highly restricted for security reasons with
mining areas
the result that human disturbance of terrestrial and nearshore areas
by means other than mining is minimal.
Biophysical Environment:
Negative Aspects
Impact
Mitigation
Terrestrial mining activities
· Terrestrial mining in the coastal zone has numerous impacts
· Mitigation is principally through
including scarring of the landscape, and the production of sediment
rehabilitation of prospected and mined
plumes which can impact terrestrial and aquatic communities.
areas and through discharging fine
tailings into slimes dams.
Beach mining activities
· Seawalls, constructed to permit `terrestrial' access to diamond
· Using material for seawall construction
deposits in the subtidal, result in physically altered shorelines and
that is equivalent to that which is
severe impacts on sandy and rocky shore fauna.
stripped from the shore allows for a
more rapid recovery of affected
communities.
Shallow water (<30 m) mining · Access to the shore by shore-based operators requires roads, camps
· In-water mining needs to be limited to
and often rock cuts.
boat based operations only.
· Nearshore pumping has numerous impacts on benthic communities
· Tailings must be dumped away from
including the creation of sediment plumes, smothering of reef with
rocky reef areas and boulder movements
discharged tailings, destabilising gravel beds, physical disturbance
need to be kept to a minimum.
by pipes, moving of boulders and kelp cutting by divers to provide
Restrictions have been placed on the
unencumbered access to mining sites.
width of lanes cut, clear-cutting and/or
repeated cutting.
Mid-Water and Deep-Water
· Fine tailings material remains in suspension for long periods and can · No mitigation.
Mining (>30 m)
impact phytoplankton, fish and marine mammals through light
reduction, nutrient enrichment, remobilization of contaminants,
clogging of fish gills and reducing oxygen levels.
· Mining process impacts benthic fauna by disturbing sediments,
· Suggested mitigation includes leaving
smothering and aggravating oligoxic conditions on the sea floor.
lanes of undisturbed sediments between
mining areas.
Anchor Environmental Consultants
7. DIAMOND MINING IN THE BCLME TOWARD INTEGRATED
ENVIRONMENTAL MANAGEMENT
The Integrated Environmental Management philosophy, encompassing scoping, impact
assessments and environmental management plans, is a large step toward the integrated
environmental management of activities affecting the BCLME. Environmental concern,
however, has had a recent birth, and the processes and mechanisms of environmental
management are still evolving. The current model is good, but a few criticisms are warranted
to take the environmental management of diamond mining in the BCLME into the future.
Criticisms of socio-economic, biophysical and environmental management as a whole are
discussed below.
7.1 Socio-economic Environmental Management
EMPRs completed to date are deficient in their attention to socio-economic impacts, and in defining
appropriate measures to mitigate or optimise these effects. In many instances, the discussion of socio-
economic impacts focuses on the positive impacts of the mining venture only, such as employment
creation, and a brief discussion of the economic spin-offs for the local economy (without expanding on
predicted local expenditure). Management actions to address the negative socio-economic impacts of
mining, such as problems associated with influx of job seekers and the infrastructural and service
capacity of the affected towns and their capacity to support mining activities, are seldom considered in
any detail. Furthermore, EMPRs rarely set management targets or goals for example, for implementing
affirmative action, and the purchase of goods and expenditure in local communities from small micro-
enterprises. Mining companies are reluctant to commit themselves to these kinds of policies, which can
be audited.
Blame for shortcomings in environmental management cannot only be levelled at the companies
concerned. There is a need for the governments of the respective countries to create incentives and to
provide appropriate guiding legislation. Perhaps the most pressing requirement in this regard, is the
need for the governments of Namibia and South Africa to redress their policies on the allocation of
diamond mining revenues. Consideration should be given to investing a certain proportion of annual
revenues to the areas which support diamond mining in order to upgrade infrastructure, stimulate
development and create employment for local residents, especially in anticipation of continued
downscaling of onshore diamond mining. Incentives such as tax breaks should be considered to
encourage companies to purchase a greater proportion of goods and services from local entrepreneurs.
7.2 Biophysical Environmental Management
Many environmental impact studies undertaken to date have been speculative desktop
assessments, or conducted after-the-fact. In most cases, pre-mining baseline data were
lacking or inadequate, which preclude detailed assessments of changes to the biophysical
environment attributable to diamond mining. In an ecosystem where natural heterogeneity in
the biophysical environment is commonplace, a great deal of uncertainty therefore remains
concerning the extent and significance of the damage caused by mining activities. For
example, despite considerable desktop effort devoted to rock lobsters, conflicts arise time and
again because speculation is not defensible. Directed field studies that recently been
completed are helping to clarify this issue, however.
A further shortcoming of many environmental impact studies is that most studies are
addressed at either a high taxonomic level, or at the level of the community. For example, the
effects of diamond mining have been examined with respect to benthic communities, sea
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birds, fish, mammals, etc. When considered as a group, more often than not the conclusions
reached are that impacts are minimal. Some species, however, may be neglected through such
an approach and there are cases where mining may in fact detrimentally impact specific
components of the community. This is not insignificant, especially if the species in question
are rare, endangered, or perhaps of commercial value. For example, beach communities as a
whole are considered resilient to disturbance. However, there is considerable body of
circumstantial evidence that suggests one component of beach communities is particularly
susceptible to diamond mining: the semi-terrestrial isopod Tylos granulatus. Human impact
on Tylos is so widespread, in fact, that it is being considered for inclusion as a Red Data Book
species. This animal warrants further attention.
7.3 Environmental Management as a Whole
Cumulative impacts are an important, although a largely ignored issue both within and
between the various users of the BCLME. Between industries, environmental management is
most often conducted in isolation. That is to say that the EMPRs of diamond mining
companies examine the effects of diamond mining, those for oil and gas exploration likewise
only examine their own direct impacts, and so on. In an ecosystem such as the BCLME that
has a myriad of users, isolated approaches may fail to uncover possible cumulative effects
between industries that could ultimately lead to environmental catastrophe. With increasing
pressure on the BCLME from fishing interests, oil and gas exploration, diamond mining,
coastal shipping and recreational use, there is a dire need for an integrated and co-ordinated
approach to the management of activities affecting this ecosystem.
On the other hand, cumulative impacts within the mining industry are also largely ignored.
Impacts such as kelp cutting, disturbance to the benthic communities, and habitat
modification, for example may act in synergy, although thus far these impacts have only been
considered in isolation. Together, they may have chronic, acute or even beneficial impacts on
the natural environment and these need to be further investigated through focused and
scientifically valuable research and monitoring programmes. Such monitoring programmes
will enable quantification of cumulative impacts in space and time, in relation to
environmental and resource sustainability. The importance of cumulative impacts become all
the more pervasive in an expanding and technologically advancing mining industry.
Environmental Management Programmes should be dynamic documents, being updating as
mining methodologies or plans change, or as new environmental information becomes
available. This is a side to EMPs that is not often seen. The plethora of monitoring activities
have little value if the results of monitoring are not objectively evaluated and likewise
incorporated within existing management programmes. Part of the problem is attributable to
the insular approach to environmental management that has been adopted, which leads to
considerable duplication in scoping, impact assessments, specialist studies and management
plans. In addition to a waste of resources, information that is collected is rarely disseminated,
with the result that mistakes can, and often are, repeated. As the problems faced by the
mining industry are largely ubiquitous through the region, considerably more effort must be
channeled into two activities: objective reviews of the information to date, and a means of
consolidating directed research and monitoring.
The criticism levelled above becomes all the more pervasive when the future of marine
diamond mining, and coastal and marine use as a whole, is considered. At present, the vast
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majority of diamond mining is terrestrial based, with marine mining enjoying only a small
proportion of the effort. Numerous coastal mines are set to close over the next 10 to 20 years
and future diamond mining effort is likely to expand into the offshore. Concomitantly, the
stage is set to see an increase in effort in both fishing, and oil and gas exploration (see other
documents in this series). Almost without question, this will lead to an increase in the number
and severity of conflicts between these sectors, as the natural resource base is finite and
shrinking, under pressure from an increasing number of users. This makes the need for co-
ordinated efforts taking a holistic approach to environmental management all the more
important.
7.4 Conclusions The Way Forward
Environmental management of the marine diamond mining industry in South Africa and
Namibia, although very much in its infancy, has made major progress. A considerable
volume of baseline information, albeit at a fairly coarse scale, has been collected and is
available for use in the management of the system. Most of the major biophysical impacts of
the mining activities on the environment have been addressed and, wherever feasible,
appropriate mitigation measures have been implemented. The total area of the marine
environment affected per annum by the diamond mining industry as a whole remains
relatively small relative to what is available. Thus, whilst some of the impacts of mining may
appear very severe in terms of the local environment, these must be placed into perspective on
a larger geographical scale. In terms of the biophysical environment, several issues still
require attention, with cumulative impacts of mining coupled with those of other users, as
well as selected single species studies being the most pressing.
Perhaps the most significant step toward an integrated approach to the management of the
environment is the establishment of fora as a means of fostering communication, education
and securing funding. In Namibia, the Lüderitz Forum was established to tackle issues
affecting all users of the marine environment and Lüderitz town. The Forum comprises
representatives of local and national government (e.g. Ministry of Mines and Energy, the
Ministry of Fisheries and Marine Resources), and the fishing and mining industry. A liaison
committee is soon to be established for the West Coast region in the South Africa on which
various industries and other coastal users will be represented. Another positive initiative has
been the formation of the South African and Namibian Marine Diamond Mining
Associations. The former association has recently adopted a coordinated approach to
environmental management through the development of a Generic Environmental
Management Programme. A consolidated environmental baseline report on the environment
of the South African west coast B, C and D concession areas was compiled in late 1997, and
is to be followed shortly by a baseline report for the A concession areas and a generic EMPR
for all four zones. Such initiatives must be commended.
In Angola, however, marine diamond mining is very much still in its infancy. Few, if any,
serious initiatives have been undertaken towards sustainable exploitation of the mineral
resources in this country. While it is good to think that much of the experience gained and
many of the lessons learned in South Africa and Namibia will put this country in good stead
for the future, several major stumbling blocks remain. Decades of civil war and continued
political instability have stifled the development of local expertise and prevented access by
foreign scientists. Consequently, there is little information available with regard to basic
knowledge of biological and ecological functioning of systems in this country. Much of the
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country lies within subtropical and tropical areas and most of the information gathered
regarding the consequences of mining in temperate ecosystems of South Africa and Namibia
will be of little value. In this regard, desktop approaches will be all but meaningless,
necessitating more costly field-based approaches in order to establish meaningful baselines on
which comprehensive impact assessments can be based.
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8. BIBLIOGRAPHY
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diamond divers, with special attention to the rock lobster, Jasus lalandii. Final Report
to NAMDEB (Pty) Ltd. December 1996.
PULFRICH, A and A. PENNEY, 1998. Assessment of the impact of diver-operated
nearshore diamond mining on marine benthic communities in the Zweispitz area,
Namibia. Report to NAMDEB Diamond Corporation (Pty) Ltd.
SCHNEIDER, G.I.C., 1998. Diamond mining off the coast of Namibia and the marine
environment. First Regional Workshop on the BCLME, Cape Town, South Africa, 22-
24 July 1998.
SCHNEIDER, G.I.C. & R. MILLER, 1998. Did nature compensate Namibia with diamonds?
Namibia Review 7(3): 1-11.
SUE LANE & ASSOCIATES, 1998. March 1998 review for DFI of CSIR Report EMAS-
C95040b: Environmental impact assessment for the proposed mining of concession
area M46/3/1607 off Lüderitz Bay: Namibia (Dated November 1995).
SUE LANE & ASSOCIATES, 1996. Environmental assessment and management plan
report for deep sea diamond mining in Namibia by Arena Mining (Pty) Ltd. October
1996.
TOMIN, B.J. 1993. Migrations of spiny rock lobsters, Jasus lalandii, at Lüderitz :
Environmental causes, and effects on the fishery and benthic ecology. M.Sc Thesis,
University of Cape Town, pp. 1-99.
WICKENS, P. & S. LANE. 1997. Deep sea investigations. Mining Environmental
Management, December 1997, p7-10.
Overview of Diamond Mining in the BCLME
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WILLIAMS, R. 1996. King of Sea Diamonds. The Saga of Sam Collins. W.J. Flesch &
Partners, Cape Town
Overview of Diamond Mining in the BCLME
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9. PEOPLE CONSULTED
South Africa
Sue Lane: Sue Lane & Associates
Lionel Philips, Alexkor, Alexander Bay
Louis Luke, DMNM Human Resources Manager, Kleinsee
Patti Wickens, De Beers Marine, Cape Town
Andy Grills, De Beers, Namaqualand
Jeremy Midgely and Romaine Kotze, Nautical Diamonds/Arena, Cape town
Piet Slot-Nielsen, Transhex, Die Punt, W.Cape
Mr Agenbag, Minerals Development, DME, Cape Town
Mr A. Eager, Communications Dept., Minerals Bureau, Pretoria
Ms.N. Botha, Statistics, Minerals Bureau, Johannesburg
Mr A. Damarupurshad, Mineral Commodity Specialist, Minerals Bureau, Pretoria
Ms. E. Swart, DME (Environmental Policy aspects), Pretoria
Mr van Rensburg, N.Cape DME, Kimberley
Mr. P. Schroeder, Ocean Diamond Mining South Africa Ltd
West Coast District Council
Namibia
Colleen Parkins, Environmental Officer, NAMDEB
Mr JJ Dohogne, Directorate of Environmental Affairs, Windhoek
Dr G. Schneicer, Director of Geological Survey, Ministry of Mines and Energy, Windhoek
Mr G. McGregor, Commissioner of Mines, Ministry of Mines and Energy, Windhoek
Mr W. Malango, Acting Director of Mines, Ministry of Mines and Energy, Windhoek
Dr. AE Macuvele, Ministry of Mines, Windhoek
Overview of Diamond Mining in the BCLME
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BENGUELA CURRENT LARGE MARINE
ECOSYSTEM
INTEGRATED OVERVIEW OF FISHERIES OF
THE BENGUELA CURRENT REGION
November
1999
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BENGUELA CURRENT LARGE MARINE
ECOSYSTEM
INTEGRATED OVERVIEW OF FISHERIES OF
THE BENGUELA CURRENT REGION
A synthesis commissioned by the United Nations Development Programme (UNDP) as an information
source for the Benguela Current Large Marine Ecosystem (BCLME) Programme
Authors
I. Hampton
30 Jeffcoat Ave., Bergvliet 7945, South Africa
D. C. Boyer
National Marine Information and Research Centre,
Ministry of Fisheries and Marine Resources, P.O. Box
912, Swakopmund, Namibia
A.J. Penney
22 Forest Glade, Tokai 7945, South Africa
A.F. Pereira
c/o BENEFIT Secretariat, Ministry of Fisheries and
Marine Resources, P.O.Box 912, Swakopmund, Namibia
M. Sardinha
Institute de Investigação Pesqueira, Ministerio das
Pescas, Ilha de Luanda, C.P. 83, Luanda, Angola
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EXECUTIVE SUMMARY
This Report gives an overview of the major living resources of the Benguela
Current Ecosystem, and of the research which has been conducted on them by
the three countries bordering the system (Angola, Namibia and South Africa) and
foreign partners, as input to management of these resources. It treats the
resources on a regional basis, and highlights trans-boundary problems which
need to be addressed through a regional rather than a national approach. The
report amplifies and updates recent summaries of scientific information on the
resources, and adds material on the legal framework and structures under which
they are managed in each of the three countries.
The distribution and habitats of the major species exploited by the purse seine,
trawl, crustacean, linefish and artisanal fisheries of the region, and of the seal
and main seabird populations, are briefly described and discussed with particular
reference to questions of stock separation and the connection between
apparently different populations. It is pointed out that a number of commercially-
important species (e.g. hake, horse mackerel, deep-sea red crab, tuna and,
probably to a lesser extent, sardine and anchovy) are distributed or move
seasonally across national boundaries, requiring regional compatability in the
research and management of these resources.
The life histories of the major exploited species are briefly outlined, with
emphasis on temporal and spatial spawning patterns, the dispersal of the early-
life stages, migration patterns of recruits and adults, and diet (particularly as it
relates to potential competition between species). The broad picture to emerge is
that the important offshore resources in the southern Benguela spawn over
various parts of the Agulhas Bank, and depend to a greater or lesser extent on
the equatorward jet current between Cape Point and Cape Columbine to
transport the early life stages to the West Coast, where much of the recruitment
takes place. Pelagic recruits return to the Agulhas Bank in the poleward counter
current close to the coast. Species which become more demersal with age (e.g.
hake and horse mackerel) tend to move into deeper water as they move south in
the early stages, resulting in complex movements between the West and South
Coasts and more widespread spawning areas. In the northern Benguela,
spawning of many of the important species is concentrated in northern
Namibia/southern Angola, and is probably influenced by movements of the
Angola-Benguela front. Juveniles spawned in this area tend to move south close
to the coast and to return northwards farther offshore when older.
The history and current status of the major fisheries of the region are discussed,
concentrating on catch trends and changes in the nature of the fisheries. Over
the past 30 to 40 years total catches in the south-east Atlantic have declined from
a peak of more than 3 million tonnes in 1968 to levels of around 1 million tonnes
per year in the 1990s. The most pronounced features in Namibia and South
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Africa have been the major decline in catches of South African and Namibian
sardine in the mid- and late 1960s respectively (followed by a dramatic further
decline in Namibia in the mid-1970s), the major decline in the West Coast rock
lobster resource (particularly off Namibia) to levels well below those in 1960, and
the major reduction in hake and horse mackerel catches off Namibia in the
1990s, due largely to the withdrawal of foreign fishing fleets after Independence
in 1990. Off Angola, the most notable feature is the sharp reduction in industrial
catches of all the most important species (e.g. sardinellas, horse mackerel and
deep-water prawns), due largely to the major reduction in foreign fishing effort
from 1985 onwards.
Changes in the abundance and distribution of the major resources, including
seals and seabirds, as revealed by acoustic, trawl and aerial surveys and catch-
based analytical methods, are discussed. VPA estimates confirm the dramatic
decline of Namibian sardine in the late 1960s and the subsequent further sharp
decline in the mid-1970s. Acoustic surveys since 1990 show that the population
dropped to its lowest ever level in 1995 (co-incident with a major Benguela Niño
in the northern Benguela), but that it has recovered somewhat since then.
Acoustic surveys of sardine and anchovy in South African waters indicate that
there has been a gradual increase in sardine abundance since the mid-1980s
(although probably not to pre-collapse levels), and show two cycles in anchovy
spawner biomass, with peaks in 1986 and 1991. The distribution of Namibian
sardine has moved northwards as the population has declined, an extreme being
reached in 1994, when sardine were only found north of the Cunene River, in
Angolan waters. Likewise, there has been a major shift in the distribution of
sardine in South Africa since the 1960s; the core of the distribution of adults
having shifted from the West Coast to the South Coast. Acoustic surveys off
Angola indicate that, in the 1990s, the biomass of both sardinella and Cunene
horse mackerel has roughly doubled compared to the 1980s. Recent swept-area
estimates of hake abundance in both Namibia and South Africa indicate that
these populations are relatively stable at present, and there is some evidence
that they could be gradually increasing. An interesting trend has been the
increase in the abundance of Merluccius paradoxus in Namibian waters since
1992, which may indicate recent expansion or northward displacement of the M.
paradoxus population from the South African West Coast. Acoustic and trawl
survey estimates of adult horse mackerel in Namibia and South Africa over the
past decade do not reveal any pronounced trends apart from a roughly 3-fold
increase in the biomass on the South African West Coast since 1991. It is
evident from CPUE indices that the abundance of line-caught species in South
Africa has declined over the past few decades, to almost zero in some cases. As
a result, the distributional ranges of many of these species has contracted, and
the magnitude and extent of their migrations has declined. Aerial censuses reveal
that the Namibian seal population was roughly halved by the effects of the 1993-
1994 extreme anoxia events in the northern Benguela, from which the population
now appears to have almost recovered. Aerial censuses have also revealed long-
term reductions in the numbers of Cape gannets and Cape cormorants on the
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West Coast of southern Africa since the 1960s, and continuing declines in
numbers of African penguins.
A number of major effects of the environment on the distribution and abundance
of commercially important resources in recent years are discussed. The most
dramatic of these was the wide-scale advection of low-oxygen water into the
northern Benguela from Angola in 1993 and 1994, and the subsequent Benguela
Niño of 1995, which appears to have severely affected the Namibian sardine
population, and its major predators (particularly seals), and to have directly or
indirectly increased mortality of juvenile hake on the Namibian shelf.
The present socio-economic value of the region's fisheries to Angola, Namibia
and South Africa is outlined. Their national importance and the balance between
the various sectors (industrial, artisanal, recreational etc.) varies considerably
between the three countries. The fisheries sectors in Angola and Namibia rank
high in national importance, for local food production in the case of Angola, and
in Namibia for exports from the industrial fishery, which are worth over 1,35 billion
N$ (approx. 225 million US$) per year at present. In both countries the sector is
an important source of employment, which is largely informal in the case of
Angola, and formal in Namibia. In South Africa, while the fishing industry is
relatively unimportant nationally, exports rival those of Namibia, and the industry
is an important source of revenue, food and employment in coastal areas,
particularly in the Western Cape Province, which yields 80 - 90% of the total
South African marine fish catch. Artisanal fisheries are currently of relatively little
importance in South Africa, but the recreational fishery for linefish is large and
varied, and directly or indirectly generates revenue and employment
opportunities which probably exceed those of the industrial fishery.
The broad national policies, legislation and formal structures for managing
marine living resources in Angola, Namibia and South Africa are sketched, and
the institutional capacity for research and management (including donor support)
in each of the three countries is outlined. Current regional marine research
programmes such as BENEFIT are briefly outlined, and other international and
regional agreements pertaining to management of the region's marine resources
are listed. Recent and current methods used to assess the size of the major
resources in each of the three countries are described in broad detail, and the
methods used to manage them discussed.
Major gaps in current knowledge of the region's resources and threats to their
rational management are discussed, with particular attention to trans-boundary
issues, which are seen to be notable for hake, horse mackerel, sardine, anchovy
and crab stocks. The major general scientific problems are seen as inadequate
understanding of stock definition (particularly for shared or migratory stocks),
inaccurate or non-existent information on basic biological characteristics
(particularly age structure) for many of the harvested species, inadequate
absolute estimates of population size and of trends in biomass, the lack of
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Operational Management Procedures based on population models for many of
the resources, and the inability to predict the effects of environmental
perturbations on resource dynamics with sufficient confidence for this information
to be used in national or regional management. In most cases these problems
are particularly severe in Angola and, to a lesser extent, in Namibia. It is noted
that the root cause of many of the trans-boundary management problems is the
lack of regional agreements and structures for research and management of
shared resources, and the shortage of manpower and funds to undertake trans-
boundary surveys and other related research activities.
Finally, particular scientific and operational problems in Angola, Namibia and
South Africa are discussed on a national basis. In Angola, where resources and
their environment have been significantly less studied than elsewhere in the
region, there are limited data series for retrospective analyses, large deficiencies
in the understanding of fundamental life history characteristics of commercially
important species, and no population models on which to evaluate management
options. Catch and effort statistics are unreliable, and fisheries regulations are
difficult to enforce owing to the extended coastline and small corps of compliance
officials. Research capacity is limited because of the small number of people
involved and the lack of appropriate local educational facilities. Most importantly,
the breakdown of basic services and infrastucture as a result of the protracted
civil war, and the severe macroeconomic problems in the country at present
seriously inhibit development of local capacity in all spheres. In Namibia, the
chief scientific challenges are the development of population models and
Operational Management Procedures which would enable alternative harvesting
strategies for the major fisheries to be formally evaluated, and the finding of
objective ways of including environmental information into management
decisions. A major operational constraint is the severe shortage of scientific and
particularly technical staff within the Ministry of Fisheries and Marine Resources
for the large number of resources which have to be studied, a problem
exacerbated by the need for local staff to spend extended periods abroad for
further education. In South Africa, the nation's strong capacity in marine science
is being threatened by a reduction in research funding, which has led inter alia to
difficulties in maintaining even essential resource-monitoring surveys, and strict
curtailment of environmentally-orientated cruises. Loss of senior research and
management staff as a result of moves to reduce the size of the Public Service
has resulted in a loss of experience and a greater load on remaining staff, which
is likely to be aggravated by added responsibilities under the new Marine Living
Resources Act.
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CONTENTS
Executive
Summary
3
1.
Introduction
9
2.
Occurence
and
Stock
Identity
12
2.1
Small
pelagic
fish
12
2.2
Trawled
fish
13
2.3
Crustaceans
16
2.4
Line-caught
species
16
2.5
Seals
and
seabirds
18
3.
Life
History
of
Major
Resources
19
3.1
Small
pelagic
fish
19
3.2
Trawled
species
22
3.3
Crustaceans
26
3.4
Line-caught
species
27
3.5
Seals
and
seabirds
28
4.
History and Current Status of the Fisheries
29
4.1
Purse
seine
fisheries
30
4.2
Trawl
fisheries 34
4.3
Crustacean
fisheries
37
4.4
Commercial
linefisheries
38
4.5
Artisanal/subsistence
fisheries
40
4.6
Recreational
fisheries
40
5.
Changes in Abundance and Distribution of Major Resources
41
5.1
Pelagic
resources
41
5.2
Trawled
species
44
5.3
Crustaceans
48
5.4
Line-caught
species
48
5.5
Seals
and
seabirds
49
6.
Effects of the Environment on Distribution and Abundance
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52
6.1
Pelagic
resources
52
6.2
Trawled
species
54
6.3
Crustaceans
55
6.4
Line-caught
species
55
6.5
Seals
and
seabirds
55
7.
Socio-economic
Importance
56
8.
Management
61
8.1
Policy
and
legal
framework
61
8.2
Research and management capacity
63
8.3
International and regional agreements and conventions
67
8.4
Management measures for major resources
68
9.
Research Gaps and Threats to Management
75
10.
Acknowledgements
80
11. References
and
Other Literature
81
12.
Acronyms
91
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1. INTRODUCTION
The Benguela Current Ecosystem can be loosely considered as covering the
continental shelf between the Angola-Benguela frontal zone in northern
Namibia/southern Angola and the Agulhas retroflection area, typically between
36 and 37 oS (Shannon and O'Toole 1998). As such, it covers the West Coast of
South Africa, the entire Namibian coast, and southern Angola (Fig. 1) to an
extent depending on the position of the Angola-Benguela front, which moves
seasonally typically between 14 and 17 oS.
Fig. 1 Southern Africa, showing the 200m isobath, considered here to delimit
the
continental shelf
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The Benguela Current is one of the world's major eastern-boundary current
systems, and is rich in pelagic and demersal fish populations, supported by
plankton production driven by intense coastal upwelling. These populations have
been heavily exploited by man, particularly since the Second World War. Total
fish catches in the south-east Atlantic climbed rapidly during the 1950s and
1960s, with the development of hake, sardine, anchovy, horse mackerel and
sardinella fisheries (Fig. 2), and a valuable fishery for rock lobster in both
Namibia and South Africa. The total annual catch peaked at over 3 million tonnes
in 1968, but it subsequently declined to a level of around 2 million tonnes in the
1970s. This was largely attributable to major declines in sardine catches off both
Namibia and South Africa, which were only partly compensated by increased
(largely foreign) catches of hake and horse mackerel off Namibia. Total annual
catches in the region subsequently dropped further to around 1.2 million tonnes
in the 1990s, with a further sharp decline in catches of Namibian sardine in the
second half of the 1970s, and the cessation of foreign trawling for hake and
horse mackerel off Namibia after her independence in 1990. Since the 1960s
there has also been a dramatic decrease in rock lobster catches, particularly off
Namibia, where catches are now some two orders of magnitude below their peak
in the 1960s. It is believed that most of these declines have been due to
overfishing, although some of the major fluctuations have probably been
influenced to a greater or lesser extent by the large-scale environmental
perturbations that have occurred periodically in the system during this period
(Shannon and O'Toole 1998).
3
Total
2,5
Hakes
2
Chub mackerel
and snoek
1,5
Horse
mackerels
1
Round herring
0,5
Anchovy
Sardine
Sardinella
1950
55
60
65
70
75
80
85
90 92 94 96 98
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Fig. 2 Cumulative catches of the principal harvested species in the
south-east Atlantic from 1950
This overview gives a brief description of the major living resources of the
Benguela Current, and of the attempts that have been made, particularly in
recent years, to manage them rationally and sustainably in each of the three
countries bordering the system. It treats the fisheries regionally rather than
nationally, and builds on material already presented in the regional Benguela
Environment Fisheries Interaction and Training (BENEFIT) Programme Science
Plan (Shannon and Hampton 1997), with particular emphasis on work carried out
since the production of that document. References have largely been kept to
recent key publications, and to a number of general articles from the region,
wherein further references may be found.
For the purposes of this overview, the Benguela ecosystem has been defined
somewhat more widely than its physical limits, to include the extremities of the
warm water systems which bound it on both sides. This is necessary, because
some of the major resources of the Benguela spend a significant part of their
lives outside the system boundaries, and are strongly influenced by interactions
between the cool waters of the Benguela and the warm water of the Angola and
Agulhas Currents.
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2. OCCURENCE AND STOCK IDENTITY
2.1 Small pelagic fish
The major fisheries for small pelagic fish off the west coast of southern Africa are
those for sardine Sardinops sagax (also known as pilchard), anchovy Engraulis
capensis, juvenile Cape and Cunene horse mackerel (Trachurus trachurus
capensis and T. trecae respectively), round herring Etrumeus whiteheadi, and the
round and flat sardinella (Sardinella aurita and S. maderensis respectively),
which are fished almost exclusively by Angola.
Sardine and anchovy live in temperate waters from southern Angola to KwaZulu-
Natal in South Africa, with both species co-existing as quasi-discrete stocks off
northern/central Namibia and off the Western Cape (i.e. between Cape Point and
the Orange River). The degree of mixing between the southern and the northern
populations of these species is unknown, but considering that the populations
spawn in different, widely separated areas and are separated by a large,
perennial area of cold, upwelled water off Lüderitz, it is probably not significant
for management purposes, except in anomalous years. The round herring occurs
over a similarly wide latitudinal range, but it appears to be most abundant east of
Cape Point, particularly over the Central and Eastern Agulhas Bank. Most of the
round herring caught in Namibian waters are juveniles, taken inshore as a small
by-catch in the purse seine fishery. Although adults are occasionally taken farther
offshore by bottom and midwater trawlers, the adult stock off Namibia is thought
to be small compared to that farther south. Interaction between these stocks is
probably of little consequence for management.
Juveniles of Cape horse mackerel (i.e. fish < about 20 cm) are most commonly
found off the west and south-west coasts of South Africa, and off northern
Namibia/southern Angola, south of the Angola/Benguela front. These fish are
believed to originate from separate spawning stocks off South Africa's South
Coast and northern Namibia respectively. Juvenile Cunene horse mackerel T.
trecae are found in subtropical and tropical waters in Angola and (occasionally)
off northern Namibia. Their distribution extends from north-west Africa to the
Angola/Benguela front, which moves seasonally between about 14 and 17 oS,
with an average position at 16 oS (Pereira 1988, Shannon et al. 1987). Because
of the highly dynamic nature of the front, it is most likely that the juvenile Cunene
horse mackerel found in southern Angola, and very occasionally in northern
Namibia, are part of a single population.
Sardinella aurita and S. maderensis are found along the entire Angolan coastline,
with the juveniles inshore, predominantly in the north. To the north their
distribution extends apparently continuously along the coasts of Congo and
Gabon, while to the south S. aurita can extend into northern Namibia in Benguela
Niño years. In the north both species undertake extensive spawning migrations
along the Angolan coast (S. aurita more so than S. maderensis), making it
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unlikely that distinctly separate stocks exist in this region. It has however been
suggested (Wysokiski 1986) that the Angolan stock of S. maderensis is
independent of the stock off the coast of Gabon.
Sardine tend to live within about 50 km of the coast, and are often found close
inshore, both in South African and Namibian waters. Anchovy have a similar
coastal distribution, but are commonly found more than 100 km offshore on the
Agulhas Bank off the Cape South Coast in the spawning season. Round herring
are found widely distributed across the shelf both on the West Coast and the
Cape South Coast, with a clear increase in size with distance offshore. Juvenile
Cape horse mackerel off both South Africa and Namibia, and juvenile Cunene
horse mackerel off Angola, are most abundant inshore, generally being found
within the 100m isobath throughout the region. S. aurita inhabits the continental
shelf and is generally found in calm saline waters (>35 ppt) at temperatures
around 24 oC. In contrast, S. maderensis is a coastal, more euryhaline species,
also generally found at temperatures above 24 oC, often in the vicinity of river
mouths (Luyeye 1995). The two species appear to be roughly equal in
abundance, except in the south where S. aurita predominates. Surveys indicate
that sardinella density is generally higher in the central (Luanda-Benguela) region
than to the north and south (Luyeye 1995).
2.2 Trawled fish
The major species caught by trawl off Namibia and South Africa are the Cape
hakes Merluccius capensis and M. paradoxus, which are caught in bottom trawls,
and adult Cape horse mackerel, which are mostly caught in midwater trawls off
Namibia and in bottom trawls off South Africa as a by-catch in the hake fishery.
Other significant by-catch species in the hake fishery in both Namibia and South
Africa are monkfish Lophius spp, kingklip Genypterus capensis, snoek Thyrsites
atun and the West Coast sole Austroglossus microlepis. In recent years, the
monk fishery in Namibia has become increasingly directed, with the West Coast
sole as the most important by-catch. On the outer Namibian shelf there is also a
valuable deep-water trawl fishery directed at orange roughy Hoplostethus
atlanticus and, to a lesser extent, alphonsino Beryx splendens and other deep-
water species. Off Angola there is a relatively small bottom trawl fishery for
Benguela hake Merluccius polli and M. capensis (in the extreme south), and
more important ones in central and northern Angola for demersal species such
as Dentex spp. and red pandora Pagellus belloti. The large-eye dentex Dentex
macrophthalmus is also taken off northern Namibia in midwater trawls, together
with jacopever Helicolenus dactylopterus, another important by-catch species.
The distributions of the three species of hake in the Benguela region are shown
in Figure 3. Merluccius polli occurs predominantly in Angolan waters, and is
caught on the shelf slope as a by-catch in the prawn fishery and by deep water
trawlers in the south, where its distribution overlaps with that of the shallow-water
Cape hake M. capensis. The two species of Cape hake are found throughout
Namibian and South African waters. M. paradoxus (deep-water hake) occurs in
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deeper water than M. capensis, although the two species co-occur at
intermediate depths (Payne 1989). Typically the former is found in water 150
800m deep, mostly at temperatures between 4 and 8oC, whereas the latter
occurs from the coast to a water depth of about 380m, in temperatures between
4 and 12 oC. It has been suggested (Payne 1989) that, in South Africa, the
relative abundance of the two species is related to the width of the shelf and the
steepness of the slope, with M. capensis predominating where the shelf is broad
and the slope steep, and vice versa for M. paradoxus. Larger individuals of both
species are found at greater depths than smaller fish, and there is little overlap in
the distribution of mature fish. M. capensis is the more common species off
Namibia, especially in the central region, although M. paradoxus has been
increasingly abundant and more widely distributed there in recent years (see
following). M. paradoxus predominates off the west coast of South Africa. It is
believed that this stock may be the origin of the Namibian M. paradoxus stock. A
second population of M. capensis, which for management purposes is treated as
a separate stock, exists in the extreme southern Benguela, chiefly over the
Agulhas Bank.
In the 1970s and 1980s, ICSEAF treated Cape stocks off southern
Angola/northern and central Namibia (15 - 25oS), southern Namibia (25 - 30oS),
the South African West Coast (30oS - 20oE), and the South African South Coast
as separate for management purposes. The species were considered together,
as the catch records did not distinguish between them Fig. 3 suggests that the
West Coast stocks of both species are probably shared between Namibia and
South Africa, although catch patterns between Lüderitz and the Orange River
indicate that there may be a measure of separation between the Namibian and
South African M. capensis stocks. In contrast, there is some evidence from
surveys (e.g. Strømme 1996) and commercial catches that, since 1990, there
has been a gradual migration or expansion of M. paradoxus into southern
Namibia and farther north, probably from South African waters. This is the only
reported evidence of significant longshore movement of any of the three hake
species, although it has previously been suggested that such shifts do occur in
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response to environmental changes such as temperature fluctuations and the
movement of de-oxygenated bottom water.
Fig. 3 Distribution of the three hake species in the Benguela ecosystem
(from Payne1989)
At least two stocks of Cape horse mackerel exist off southern Africa, viz. off
northern Namibia/southern Angola, and off the Western Cape. These stocks
were once believed to be genetically separated by the environmental barrier of
the Lüderitz upwelling cell, with only a limited interchange between them.
However, the finding of large adults on the bottom across the shelf south of
Walvis Bay in recent Namibian surveys (E. Klingelhoeffer, NatMIRC, pers.
comm.) raises the question of a possible connection between this part of the
population and that on the West Coast of South Africa. This is a regional question
of major importance for managing this trans-boundary fishery. Opinion is divided
on whether the horse mackerel on the Cape West and South Coasts form a
single or separate stocks, with catch patterns suggesting the former and genetic
studies the latter. There is little information regarding the stock structure of
Cunene horse mackerel in Angolan waters, although Sardinha (1996) has
suggested on the basis of biological data and distribution patterns that there are
separate self-sustaining populations in the north and south of Angola. The
hypothesis is currently being tested genetically (Sardinha and Nævdal,
submitted). (CHECK WITH STAN/ROB LESLIE)
Orange roughy in Namibia are found mainly over the shelf between about 600m
and 1000m depth at bottom temperatures of between 3 and 7 oC (A. Staby,
NatMIRC, pers. comm.). The fish tend to be concentrated over hard substrata in
a number of small areas, particularly during the spawning season. Alfonsino tend
to be more widely distributed over the outer shelf, between about 400 and 700m.
The degree to which the distribution of the two species extends into Angolan and
South African waters, and the extent of any longshore migrations, is at present
unknown.
The main commercial species of monkfish found in southern African waters are
Lophius vomerinus (previously known as Lophius upsicephalus) and Lophius
vaillanti. The former is found from northern Namibia to the East Coast of South
Africa, but the latter only north of Walvis Bay. Both are demersal species, mainly
found at depths of between 150 and 400m. Two separate recruitment areas for L.
vomerinus have been located in Namibia: off Walvis Bay and near the Orange
River. The relationship between these recruits and L. vomerinus to the south is
unknown, as is the extent of any longshore migrations of adults. Nonetheless, it
seems reasonable to assume that there is some interaction between the
population(s) on the South African West Coast, and that found around the
Orange River, in particular.
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Demersal fish caught commercially by trawl in Angola can be grouped into
species occurring below the thermocline along the continental shelf, and species
found above, below and in the thermocline. Sparids are the most important in the
former group. particularly the large eye dentex Dentex macrophthalmus, which is
fished between 60 and 300m depth between Lobito and as far south as Walvis
Bay (Constança 1995). Other important species are the Angola dentex Dentex
angolensis and the red pandora Pagellus belloti, which occur across the shelf to
depths of around 300m (Bianchi 1986). These three species together usually
make up more than half of the demersal catch. In the latter group the most
important species is the bigeye grunt Brachideuterus auritus. A significant part of
the demersal trawl catch consists of deep-water prawns and to a lesser extent,
deep-water red crab, which are discussed in the following Section.
2.3 Crustaceans
The major crustacean fisheries along the west coast of southern Africa are those
for the West Coast rock lobster Jasus lalandii off South Africa and Namibia, the
red crab Chaceon maritae off northern Namibia and Angola, and for the deep-
water rose prawn Parapenaeus longirostris and striped red prawn Aristeus
varidens off northern and central Angola.
J. lalandii is a spiny lobster associated with the cool upwelled waters of the
Benguela. It occurs in commercially exploitable densities from east of Cape Point
to approximately 25oS, and at lower densities beyond its core distribution. Close
inshore it is caught by hoopnets deployed from dinghies and by recreational
divers, but in deeper waters is harvested by traps.
C. maritae occurs on the slope of the continental shelf from about 27 oS off
Namibia, northwards to Angola, Congo and the Ivory Coast. Off Namibia it is
found on soft mud substrata at depths of between about 300 and 900m, and is
harvested solely by Japanese vessels using traps. Off Angola it is found within a
similar depth range, particularly in the southernmost area, and is taken in traps
and (occasionally) bottom trawls. It has recently been shown from tagging studies
(Le Roux 1997) that adult females migrate from Namibia to Angola, suggesting a
single stock in the region, which needs to be managed jointly by Namibia and
Angola.
Parapenaeus longirostris is essentially an Atlantic Ocean prawn, found from
Portugal to Angola in the east, and from Massachusetts, USA, to French Guiana
in the west, whereas Aristeus varidens is an East Atlantic species, found from
Rio de Oro (24 oN) to 18 oS (off Namibia). The depth disrtribution of the two
species differ. P. longirostris is found on the continental shelf and upper slope,
between 50 and 400m depth (López Abellán and de Cárdenas 1990) over sandy
bottoms. A. varidens lives on the slope, mainly between 400 and 800m depth,
and is strongly associated with muddy bottoms. The size of both species
increases with depth, more so in the case of P. longirostris than A. varidens.
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Angolan-Spanish surveys have revealed that P. longirostris have a more
homogeneous distribution than A. varidens, which tends to concentrate in several
areas, mainly related to submarine canyons. Concentrations of P. longirostris
tend to occur around recruitment areas.
2.4 Line-caught species
The linefisheries of the Benguela Current and adjacent waters exploit a large
number of species. They can be broadly classified into a) inshore reef fishes,
which are mainly resident on shallow nearshore reefs and have a limited
geographic distribution, b) migratory shoaling species, where the adults
aggregate and migrate rapidly over large distances, usually as part of annual
migratory cycles, and c) offshore large pelagic species such as tuna and billfish,
which form large, highly-migratory straddling stocks that cross the borders of
many countries, and even oceans.
In Angola, line-caught species belonging to the first two groups make up more
than 40% of the total catch by the large inshore artisanal/subsistence fishery
which extends along the entire coast. The most important groups caught by line
are dentex, croakers (Sciaenidae) and groupers (Serranidae). Catches are
highest in the provinces of Benguela, Namibe and Luanda (Anon. 1998a). The
recreational fishery for linefish in Angola is underdeveloped and negligible
compared to the artisanal/subsistence fishery.
The silver kob Argyrosomus inodorus is the most important of the linefish species
caught commercially in Namibia, with roughly equal amounts being taken by
commercial fishermen and recreational anglers. Other important angling species
in Namibia are the steenbras Lithognathus aureti, the blacktail Diplodus sargus
and the galjoen Coracinus capensis.
Off the South African West Coast, the dominant reef fish in the catches is the
hottentot Pachymetopon blochii, which has been an important contributor to
artisanal/subsistence linefish catches off the West Coast since the early part of
the century. It is a highly resident species, which makes it susceptible to localised
depletion in heavily fished areas. In contrast, the galjoen Coracinus capensis,
which is a major shore-angling species off Namibia and the West Coast of South
Africa, is highly migratory. Tagged galjoen have been found to have moved from
northern Namibia to east of Cape Point.
Snoek is by far the most important migratory linefish species caught
commercially on the West Coast of South Africa, and is important in Namibia as
well. It is found along the entire southern African coast from southern Angola to
Cape Agulhas, mainly in cool upwelled water, and is a major predator on pelagic
fish in the region. Snoek were historically considered to form a single stock
extending from Cape Agulhas to northern Namibia, and to migrate seasonally
between these regions (e.g. Crawford et al. 1990). However, a recent study of all
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available evidence (Griffiths, in prep.) suggests that there may be two separate
sub-populations in Namibia and South Africa respectively - with medium-term
(of the order of five years) exchange between them in response to environmental
events and food availability.
Of the large pelagic species taken in the region, the most important in the
southern part is the albacore or longfin tuna Thunnus alalunga, which is currently
caught by South African and Namibian pole and line vessels within territorial
waters from south of Cape Point to Lüderitz. The species is also exploited by
Asian high-seas longliners off both countries. The stock is believed to be part of a
single southern Atlantic stock, separated from the southern Indian Ocean stock
by the warm water of the Agulhas current. There is also a longline fishery for
bigeye tuna Thunnus obesus along the edge of the shelf in both countries, mostly
by Asian high-seas vessels. It is not known whether these fish form part of an
Indian Ocean, Atlantic Ocean or circumglobal stock. In Angola the most important
species taken by local baitboats is the yellowfin tuna Thunnus albacares, while
bigeye tuna is the major constituent of the Japanese longline fishery. Yellowfin
form part of an Atlantic population, which spawn off Brazil and the Gulf of Guinea,
and are most abundant in southern Angola in summer.
Finally, mention must be made of the Cape hake Merluccius capensis, which
although primarily a trawl-caught species, is also caught by lines off South
Africa's South East Cape, and (to a lesser extent) Namibia, using both hand and
hydraulically-hauled longlines. The South African fishery grew out of an
experimental longline fishery for kingklip in the 1980s, which severely depleted
that stock.
2.5 Seals and seabirds
The Cape fur seal Arctocephalus pusillus pusillus occurs along the southern
African coast between Algoa Bay and southern Angola and is harvested in
Namibia. Although the harvest is low compared to earlier times (the fishery is
centuries old), seals have been included in this overview because they are major
top-predators in the Benguela, whose dynamics have been strongly affected by
fluctuations in a number of the major fish resources of the region, making them
important visible indicators of environmental change. The same is true of
resident seabirds such as the Cape gannet Morus capensis, the Cape cormorant
Phalacocorax capensis and the African penguin Spheniscus demersus, which
breed mainly on nearshore islands and guano platforms off Namibia and South
Africa, and feed largely on pelagic fish such as sardine and anchovy. The
dynamics of pelagic fish stocks is strongly reflected in changes in abundance,
diet and breeding success of the seabirds, to the extent that in South Africa,
consideration is being given to using this information directly in the management
of the sardine and anchovy fisheries.
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3. LIFE HISTORY OF MAJOR RESOURCES
3.1 Small pelagic fish
Sardine and anchovy
Off Namibia, sardine spawn largely within 60 km of the coast in two main areas,
one off Walvis Bay and the other farther north, in the mixing zone south of the
confluence of the Benguela and the Angola Current systems. In the northern
area, peak spawning (mainly by young adults) occurs near the 200m isobath in
late summer/autumn in water temperatures between 19 and 21 oC, whereas
spawning farther south (mainly by older fish) takes place in summer in cooler
water close to upwelling zones. Since the collapse of the sardine stock in the
1970s (Section 4.1), spawning in the south has diminished in importance. The
distribution and movement of anchovy off Namibia is similar to that of sardine
there, but significant spawning only occurs north of Walvis Bay. The larvae of
both species drift south close to the coast, recruiting as 0-group fish into the
fishery in the cool upwelling areas near Walvis Bay. This is followed by a return
northward migration of juveniles and young adults to the northern mixing area,
where they first spawn. In the case of sardine, older fish subsequently return
south again to spawn in the Walvis Bay region, although this migration is
believed to have decreased in importance since the collapse of the fishery. The
behaviour of sardine and anchovy off Namibia is analagous to that found in other
upwelling systems, such as those off California, Peru and north-west Africa
(Bakun 1995), where both spawning and recruitment occur downstream of the
principal upwelling cell (Lüderitz in this case).
In the past, sardine in the southern Benguela have spawned in two areas, one of
large adults in cool water west of Cape Columbine, and the other of younger fish
in warmer water east of Cape Point, inshore of the Agulhas Current, analagous to
the two sardine spawning areas off Namibia. However, since the major stock
decline in the mid-1960s, there has been little evidence of spawning on the West
Coast, and it seems that the stock is now perpetuated mainly by the younger
adults spawning over the Agulhas Bank, particularly the Western Bank, between
Cape Point and Cape Agulhas. Anchovy also spawn mainly over the Agulhas
Bank, somewhat offshore of the sardine, in the upper mixed layer, in water
temperatures ranging between 17 and 19 oC. Peak anchovy spawning is in early
to mid-summer, whereas sardine spawn over an extended period, with weak
maxima during late winter/early spring and late summer. In contrast to the
northern Benguela, spawning occurs mainly upstream of the main upwelling
centres of Cape Point and Cape Columbine. Eggs and larvae are transported
from the Western Agulhas Bank to the West Coast (Fig. 4) between the 200m
and 500m isobaths (Fowler and Boyd 1998), along the offshore boundaries of the
upwelling cells by a perennial equatorward jet current, leading to recruitment
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downstream of the upwelling cells. Bakun (1995) has noted that this is a reversal
of the normal spawning and recruitment pattern in other eastern-boundary
upwelling areas (e.g. the northern Benguela, California Current and Canary
Current), the difference originating from the right-angular configuration of the
coastline in the southern Benguela.
Fig. 4 Conceptual model of anchovy migration, constructed from acoustic
survey data
and trends in length in research midwater trawl catches (from Hampton
1992)
Sardine and anchovy larvae transported past Cape Columbine are either carried
offshore and lost to the system, or are transported northwards and inshore
(possibly assisted by active swimming as they develop), leading to recruitment of
both sardine and anchovy inshore along the West Coast at least as far north as
the Orange River (Fig. 4). There is evidence that in normal years, the northern
limit of the dispersal is the southern edge of the Lüderitz upwelling cell, which
causes the larvae either to be carried far offshore, or to be drawn inshore by
compensatory flow and returned south by the inshore poleward counter-current.
It has been suggested that in years when this cell is abnormally weak (as in
1987), pelagic larvae spawned in Cape waters may be carried past the Lüderitz
"barrier" and recruit into the southern Namibian fishery, linking the South African
and Namibian pelagic fisheries. This may have occurred in 1987, when an
unexpectedly large number of anchovy recruits was caught in southern Namibia,
resulting in catches roughly an order of magnitude higher than in the previous
and following years.
Once inshore, the sardine and anchovy recruits off South Africa move south
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close inshore along the West Coast in autumn and winter, assisted by the
poleward counter-current. They are possibly retained for a period in St Helena
Bay before reaching the Agulhas Bank in early summer, towards the end of their
first year of life. It is during this period that they are exploited by the purse-seine
fleet, which mainly operates from ports on the West Coast. Adults tend to move
eastward and (in the case of anchovy) offshore, with increasing age, although
there is some return of older fish to the West Coast from the outer edge of the
Agulhas Bank, probably assisted by the jet current off the Cape Peninsula.
A portion of the sardine population (mostly fish in their second year of life)
undertakes a pronounced and well-documented inshore migration into the shelf
waters of KwaZulu-Natal each winter (known locally as the "Sardine Run"), to at
least as far up the coast as Durban. This is probably in response to the eastward
retreat of warm subtropical water close inshore at that time of the year, and is
assisted by equatorward counter-currents inshore of the Agulhas Current. The
migration may be analagous to the movement of young Namibian sardine
towards the subtropical system boundary in winter. It is most probable (though
not yet demonstrated) that the surviving fish return rapidly to the Agulhas Bank
later in the year in the strongly flowing Agulhas Current slightly farther offshore.
Analyses of stomach contents up to the end of the 1970s suggested that the
diets of sardine and anchovy in the Benguela are similar, with phytoplankton as
the main food source. However, laboratory and field studies since then have
shown that zooplankton is more important in the diet of both species than was
previously believed to be the case. Certainly, juvenile sardine and anchovy, and
adult anchovy, feed primarily on zooplankton, although adult sardine appear to
utilise more phytoplankton in areas of consistently high phytoplankton
abundance. Little is known about the extent to which sardine and anchovy
compete for habitat and food in the Benguela ecosystem, but a recent field study
on feeding in mixed schools of juveniles, in which a clear size difference was
found in the zooplankton taken by the two species (Louw et al. 1998), suggests
that direct competition may be limited, at least in the younger stages.
Sardinellas
The main spawning area of S. aurita and S. madarensis is thought to be between
5 and 7 oS (Pointe Noire to south of the Congo River), with peak spawning in
March-April. There appears to be a seasonal longshore migration pattern for both
species, with an equatorward movement towards the spawning grounds during
the first part of the year, and a return poleward migration of adults in the second
half of the year to central and (in the case of S. aurita) southern Angola. Juvenile
S. aurita are encountered over the whole littoral zone from Cape Lopez in Gabon
to Baia dos Tigres in southern Angola. Upon reaching a length of 10 14 cm, the
juveniles leave the littoral zone, and remain for some time in shallower shelf
waters before joining the adult stock farther offshore (Troadec and Garcia 1980).
Juvenile S. maderensis appear to be largely concentrated inshore north of the
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Congo River throughout the year (from data in Wysokiski 1986).
Little is known about the diet of sardinellas in Angola, although French studies in
the 1970s found that the diet of both S. madarensis and S. aurita in Congolese
waters consisted almost entirely of the copepod Calanoides carinatus.
Round herring
Little is known about the seasonality of round herring spawning in the Benguela,
although from ichthyoplankton surveys in the south, it appears that there at least,
spawning probably occurs throughout the year, reaching a peak between late
winter and early summer. The early life history of round herring spawned on the
Agulhas Bank appears to be similar to that of sardine and anchovy spawned
there, with the ichthyoplankton being transported to the West Coast by the same
jet current, leading to recruitment along the West Coast at the same time of the
year as sardine and anchovy recruitment, and movement onto the Agulhas Bank
towards the end of the first year of life. The fish appear to move eastwards and
offshore with increasing age, inhabiting the entire Agulhas Bank, at least as far
east as Port Elizabeth (Roel and Armstrong 1991). As with sardine and anchovy,
there is probably some return of older fish to the West Coast from the outer
regions of the Bank.
Round herring is a particulate feeder, whose diet in South African waters consists
exclusively of zooplankton (mainly copepods, euphausiids and decapods).
Juveniles form pelagic shoals in the upper mixed layer, but adults perform
pronounced diel vertical migrations, migrating from near the surface at night to
near-bottom waters during the day, often passing through a temperature gradient
of more than 10 oC.
3.2 Trawled species
Hakes
Cape hakes spawn in midwater throughout the year, with a peak in early summer
for both M. capensis and M. paradoxus, and a secondary peak in late summer for
M. paradoxus in the southern Benguela. Most M. paradoxus spawning is thought
to take place along the edge of the Agulhas Bank, but spawning also occurs over
the shelf-break west of St Helena Bay and off central Namibia. In the latter
region, M. capensis spawn most frequently between 160 and 250m depth,
spawning starting earliest in the shallower waters. The eggs of both species are
concentrated around the depth of the thermocline, and the dispersal of M.
paradoxus eggs and larvae produced on the South Coast could be similar to that
of the pelagic fish spawning there, resulting in young M. paradoxus being plentiful
between Cape Columbine and the Orange River. To the north, 0-group M.
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capensis are particularly abundant off Walvis Bay, which appears to be a nursery
area. Juveniles of this species are also plentiful off the Orange River and south to
about Cape Columbine, sometimes co-occuring with pelagic fish recruits in
winter, on which they feed (particularly on anchovy). As with the pelagic recruits,
juvenile hake in the Orange River area move south as they grow older, but unlike
them they tend to move offshore as they move south.
There is evidence that off the West Coast of South Africa, juvenile M. paradoxus
move inshore in summer and offshore in winter, in response to changing feeding
regimes. The adults, which tend to concentrate in depths greater than about
500m in summer and autumn, move inshore in spring to depths of around 300m,
and then return offshore, movements which are probably related to both
spawning and feeding. Off Namibia, M. capensis follows a similar inshore
migration during the spawning season in early summer, followed by an offshore
migration in late summer.
Cape hakes feed both close to the bottom and in midwater, and tend to be off the
bottom at night, although no clear feeding periodicity in either M. capensis or M.
paradoxus has been demonstrated, except in the case of juvenile M. capensis,
which off the West Coast of South Africa have been observed to move off the
bottom at night to feed on pelagic prey such as juvenile anchovy, and to return to
the bottom before dawn (Pillar and Barange 1995). Recent studies (Pillar and
Barange 1998) have indicated that M. capensis adults on the South African West
Coast also move into midwater at night in response to the vertical migration of
their prey, but that they only return to the bottom when satiated, regardless of
time of day. This results in aperiodic, asynchronous vertical movements of
individuals, depending on food availability and recent feeding activity. This lack of
a distinct diel feeding rhythm has also recently been reported by Huse et al.
(1998) from studies on the behaviour of M. capensis and M. paradoxus at a
location on the central Namibian shelf, although they did find some evidence of
increased feeding in the early evening, in common with earlier studies of M.
capensis feeding in the same area.
Cape hakes are opportunistic feeders, resulting in considerable seasonal and
spatial variability in their diet. On the South African West Coast, young M.
capensis and M. paradoxus feed predominantly on planktonic crustaceans
(particularly euphausiids), juvenile anchovy (by M. capensis), lightfish Maurolicus
muelleri and lanternfish Lampanyctodes hectoris (by M. paradoxus), the diet of
both species becoming increasingly piscivorous with age (Punt et al. 1992).
Squid, epipelagic fish and, to a lesser extent, mesopelagic fish such as lightfish
and lanternfish comprise a significant proportion of the diet of adult M. capensis,
but in the larger fish the principal diet items are small M. paradoxus, small M.
capensis (to a lesser extent) and other demersal species (Punt et al. 1992). With
increasing age, M. paradoxus becomes increasingly cannibalistic on young M.
paradoxus, which together with squid, crustaceans and mesopelagic fish
constitutes most of the diet of the large mature adults on the Cape West Coast.
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In contrast, more than 90% of the diet of large M. capensis on the Agulhas Bank
consists of pelagic fish (particularly anchovy), horse mackerel and young M.
capensis, the size of prey increasing with hake size (Pillar and Wilkinson 1995).
Cannibalism on M. capensis appears to be higher than on the West Coast, but
the interspecific (hake-on-hake) predation somewhat lower.
The diet of hake in Namibia is similar to that in South Africa (see summary in
Gordoa et al. 1995), the chief difference being the greater importance of
myctophids (particularly for M. paradoxus), and the significant proportion of
gobies Sufflogobius bibartus in the diet of both species. As in South Africa, both
species become increasingly piscivorous with age, and hake-on-hake predation
becomes increasingly important.
Because of their catholic feeding habits and abundance, hake are extremely
important predators in the Benguela. For example, Punt et al. (1992) have
estimated that Cape hakes in South African waters could consume as much as 6
million tonnes of food annually. Based on estimates of stock size in Namibia, it
would appear that consumption there could be as high.
Horse mackerels
Cape horse mackerel T. trachurus capensis off the West Coast of southern Africa
have broad spawning areas, with most intense spawning in warmer waters
immediately west of the shelf-break in both regions. Egg and larva surveys in the
1970s (O'Toole 1977) showed that in Namibia the heaviest spawning occurs in
the north between October and March in the mixing zone of warm oceanic water
and cool coastal water, and that the timing of spawning is closely linked with the
duration and intensity of mixing. Nursery areas exist in both the southern and the
northern parts of the ecosystem, adjacent to the spawning grounds but closer
inshore, and there are substantial longshore and cross-shelf migrations of both
juveniles and adults.
Off Namibia, juvenile Cape horse mackerel live inshore, the smallest fish being
found farthest north. Slightly larger individuals appear to migrate south towards
Walvis Bay, especially in winter. Maturing fish move offshore and northwards to
spawn, the adults generally occuring north of 21 oS.
Off the Western Cape, juveniles also occur inshore and the adults farther
offshore. The movements of the fish with increasing age, and particularly the
interchange between the West and South Coast populations, are particularly
complex, as can be seen from a recent migration model postulated by Barange et
al. (1998), reproduced here as Fig. 5. Note that the life history in the first year of
life is similar to that of sardine and anchovy, with spawning on the South Coast
leading to recruitment on the West Coast in the following year, probably driven by
the same transport mechanisms. Recruitment occurs about three months earlier
than that of sardine and anchovy, but overlaps with it to some extent, resulting in
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a by-catch of juvenile horse mackerel in the pelagic fishery. Thereafter the
species diverge, with the horse mackerel becoming more demersal and moving
offshore, probably ultimately leading to spawning over the shelf-break on the
West Coast. Some of these fish however move onshore again in winter in their
second year of life, and move onto the Western Agulhas Bank, assisted by the
poleward counter-current on the inner shelf. These fish reach maturity at two
years of age and move eastwards and offshore with increasing age, leading to
spawning across the entire Agulhas Bank, which peaks at different times on the
Western and Eastern Banks and which, on the Western Bank at least, appears to
be closer inshore in winter than in summer. Barange et al.(1998) suggest that
adults on the Eastern Bank move southward and westward to spawn on the
Central Bank in spring, a movement which would favour transport of the
ichthyoplankton to the West Coast. They also suggest that there is some
secondary recruitment directly into the numerous bays of the South Coast from
spawning farther offshore, probably aided by the inshore movement of spawners
in winter. However, most of these hypotheses are still tentative and need rigorous
testing.
Fig. 5 Conceptual model of Cape horse mackerel migration patterns in the
southern
Benguela, constructed from acoustic and research trawl information
(from
Barange et al. 1998)
According to Troadec and Garcia (1980), the core spawning area of the Cunene
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horse mackerel is off Mauritania and Senegal, where spawning peaks from
February to June. Although spawning undoubtedly occurs farther south as well,
including in Angolan waters, little has been reported about the locality and timing
of any such spawning. Little is also known about the seasonal distributional
patterns of the different life history stages of the species off Angola, although the
fact that at the height of the fishery in the 1960s and 1970s, inshore catches used
to show a sharp peak in October/November co-incident with a rise in water
temperature, has led to suggestions that there is a seasonal inshore migration in
response to changing environmental conditions. This is supported by survey
data, which indicate that the proportion of the population in central Angola is
highest in summer (Sardinha 1996).
Cape horse mackerel up to the age of two years feed near the surface and are
planktivorous. The diet, which consists mainly of copepods, is similar to that of
sardine and anchovy, and juveniles up to about 10 cm in length can co-exist in
schools with sardine and anchovy. Adults off the west coast of southern Africa
are opportunistic feeders on euphausiids (which constitute 95% of their diet in
Namibia), polychaete worms, chaetognaths, squid, various crustaceans and fish
such as gobies Sufflogobius bibartus, lanternfish and lightfish. Older horse
mackerel tend to feed in midwater, and their diet is similar to that of Cape hakes
of similar size. Accordingly, there may be interspecific interaction between Cape
horse mackerel and Cape hakes, with a decrease in the abundance of the one
species benefiting the other, and vice versa. Pillar and Barange (1998) showed
that adults on the Cape South Coast feed predominantly on copepods close to
the bottom in late afternoon, migrate in synchrony into midwater at dusk, clearly
for purposes other than for feeding, and return to near-bottom at dawn. Sardinha
(1996) reports that in Angolan waters, horse mackerel of both species undergo a
similar diel vertical migration. There have been no comparable studies in
Namibian waters, but it would appear from the fact that adult horse mackerel
there are caught by midwater trawl throughout the 24-hour period that their
vertical migratory behaviour in this region may be different from that to the north
and south.
Deep-water species
Orange roughy off Namibia have a short spawning period of about a month in
July/August, when they spawn in dense concentrations close to the bottom in
small areas typically no more than 10 - 100 km2 in extent. They are exceptionally
long-lived and slow-growing, possibly only reaching sexual maturity at around 25
years off Namibia, and may have a maximum lifespan of over 100 years. The fish
have a low reproductive rate, which together with their aggregating behaviour,
makes them highly vulnerable to over-fishing. Alfonsino Berxy splendens are
distributed over a wider area and are probably more productive. Little is known
about their spawning behaviour or breeding habitat.
Dentex
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Dentex macrophthalmus spawn throughout the year with a peak between
October and April. The most intensive spawning occurs between Baia dos Tigres
and the Cunene River at depths between 25 and 110m (Kuderskaya 1985). Little
is known about migration patterns, except that according to Wysokiski (1986),
the stock migrates shorewards in summer and offshore in winter. Even less has
been reported on the life histories of the other commercially exploited demersal
fish in Angolan waters.
3.3 Crustaceans
West Coast rock lobster
J. lalandii has a well-defined moulting and spawning cycle. Adults moult once per
year, the males in spring and the females in late autumn/winter, after which
mating takes place. Egg-hatching peaks in October-November and the
phyllosoma larvae remain planktonic for a long period, drifting in oceanic sub-
gyres until they reach the puerulus (free-swimming) stage and settle. Females
reach sexual maturity about five years after settlement, at a greater length in the
south than in the north. Maturing males grow faster than females, resulting in the
fishery being based largely on males. The adults are generally distributed
offshore of the juveniles, except in the north, where the population is constrained
close to the coast by low-oxygen water. J. lalandii feed largely on mussels, in
particular the ribbed mussel Aulacomya ater, which is abundant in the rocky
subtidal zone of the West Coast. In areas of low mussel abundance, the diet
consists mainly of echinoderms (sea urchins and starfish), gastropods,
bryozoans, polychaetes and seaweeds. The principal predators on J. lalandii are
octopus, dogsharks, hagfish, whelks (on injured or weakened animals) and
young seals. Cannibalism is known to be prevalent in overcrowded situations,
particularly among juveniles.
Deep-sea red crab
Chaceon maritae in Namibia appear to spawn throughout the year, judging from
the fact that no seasonal cycles in moulting and egg-bearing have been found
there (Le Roux 1997). Adult females generally live in shallower water than males,
and virtually all egg production and larval release takes place on the shallower
part of the continental slope; a pattern which has also been found in Angola. The
fact that the migration from Namibia to Angola is almost entirely by females
suggests that this is a spawning migration.
Deep-sea prawns
Parapenaeus longirostris spawn throughout the year, with peaks in July and
December. Sobrino and de Cardenas (1989) state that females reach sexual
maturity at a carapace length of 21.6 mm. According to López Abellán and
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Garcia-Talavera (1992), there are nursery areas between 8 and 9 oS and
between 10 and 11 oS. Eggs are demersal and the larvae planktonic. The larvae
enter the post-larval phase at a length of 12 mm. Juveniles are concentrated
between depths of 50 and 70m, where recruitment takes place. A sampling
programme has shown that there is a major recruitment peak between January
and March, and a lesser one in August-September (López Abellán et al. 1993).
Aristeus varidens appear to spawn throughout the year, with a peak in December
and probably another in April-May. First maturity is reached at a carapace length
of about 25 mm (Sobrino and de Cárdenas).
3.4 Line-caught species
Snoek spawn along the edge of the shelf off the West Coast of South Africa and
the western Agulhas Bank, and off southern Namibia, mainly from July to
October. There is also some evidence of spawning farther north. It has been
suggested that in South African waters the ichthyoplankton is transported by
prevailing currents to a primary nursery ground north of Cape Columbine, and to
a secondary one east of Danger Point on the South-West Coast (Griffiths,
submitted). Juveniles tend to recruit inshore and remain as locally migratory
shoals in nearshore nursery areas until they approach maturity, when they join
the adult population. Their cross-shelf distribution on the inner shelf is determined
by prey availability, and includes a seasonal inshore migration in autumn in
response to pelagic fish migration patterns. Adult snoek are found throughout
their distributional range, moving offshore and somewhat southwards to spawn.
Other than this, there do not appear to be any seasonal trends in longshore
movements of adults in South African waters (Griffiths, in prep.). Migrational
patterns of juveniles and adults in Namibian waters have not been established
with any certainty.
Albacore, the main contributor to the South African and Namibian large pelagic
fisheries at present, are believed to migrate across the southern Atlantic to South
America, and then northwards to spawn in the tropical central Atlantic. Juveniles
occasionally recruit into waters off the Western Cape, but most of the fish caught
are large reproductively inactive adults, following and feeding on the rich pelagic
prey in the Benguela and Agulhas Current systems.
3.5 Seals and seabirds
The Cape fur seal breeds on small rocky nearshore islands and, most
importantly, at six mainland colonies on the Namibian and northern Cape coasts
where human access is restricted. Two of these colonies (Kleinsee in the
northern Cape and Atlas Bay near Lüderitz) are believed to be the largest
mainland seal colonies in the world. The breeding season, during which pupping
is followed almost immediately by mating, lasts for 6 to 8 weeks in
October/November. Pups are weaned at an age of 8 to 10 months, and thereafter
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forage widely. While attending their pups, adult cows feed within a few days
range of the colonies, but the bulls appear to have separate feeding grounds,
probably considerably further offshore. Much of the diet is made up of fish, of
which commercial pelagic fish and hake are the most important on the South
African West coast, and the bearded goby Sufflogobius bibartus (a non-
commercial species), horse mackerel and juvenile hake the most important off
Namibia. It has been estimated that seals in the Benguela consume about 1
million tonnes of fish annually, which is of the same order as the total annual fish
catch in Namibia and South Africa.
The Cape gannet breeds on islands off southern Namibia and the West and
South Coasts of South Africa, usually from September to November. The birds
range widely during the non-breeding season, following their prey (largely sardine
and anchovy), which they capture by plunge-diving. The Cape cormorant breeds
mostly on nearshore islands and guano platforms, but also at islands within
estuaries and lagoons, sewage works and on mainland cliffs. The breeding
distribution extends from northern Namibia to Algoa Bay. They are generally
dependent on large surface schools of fish, which they capture by pursuit-diving,
and do not forage as widely as gannets. Anchovy and sardine are the preferred
prey species, with bearded goby an important prey in southern Namibia. The
breeding range of African penguins extends from Algoa Bay to Sylvia Hill, south
of Walvis Bay. They generally breed on islands, although there are a few small
mainland rookeries in South Africa and Namibia. Pelagic shoaling fish,
particularly sardine and anchovy, are the most important prey, which are caught
by deep pursuit-diving. As with the Cape cormorant, the bearded goby has at
times been an important prey off Namibia, particularly when sardine have been
scarce.
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4. HISTORY AND CURRENT STATUS OF THE FISHERIES
Industrial catches of the major species in each country in 1997 are summarised
in Table 1. Note that zeroes in parenthesis indicate an assumed zero catch in
the absence of data to the contrary. A more general discussion of the history and
current status of each sector of the fishery follows.
SPECIES
ANGOLA
SOUTH AFRICA
TOTAL
NAMIBIA
Pelagic fish
Sardine
(0)
27 892
116 992
144 884
Anchovy
(0)
2 525
60 095
62 640
Juvenile Cape and
138 000 (1996)
88 295
12 727
239 022
Cunene horse
(Mainly T. trecae) (T. t. capensis)
(T. t. capensis)
mackerel
Sardinellas
50 000 (1996)
0
0
50 000
Round herring
(0)
5 084
92 209
97 293
Trawled fish
Hakes
720
108 594
143 053
252 367
(Mainly M. polli)
(M. capensis and M.
(M. capensis and M.
paradoxus)
paradoxus)
Horse mackerels
(0)
213 577
22 984
236 561
(all trawl methods)
(T. t. capensis)
(T. t. capensis)
Monkfish
(0)
10 259
7 640
17 899
Other demersal
20 000
7 145
24 172
51 317
species
(Mainly Dentex,
(Kingklip, sole, etc.)
(Kingklip, snoek,
croakers and grunters)
sole, etc.)
Deep-water species
(0)
20 608
647
21 255
(Mainly orange roughy)
Crustaceans
West coast rock
0
307
1 726
2 033
lobster
Crabs
1 880
739
113
2 732
Deep-water prawns
5 600 (P. longirostris)
0
0
6 950
1 350 (A. varidens)
Linefish
Tuna
910 (1995)
38
3 158
4 106
Other commercial
unknown
8 671
12 132
20 803
218 460
493 754
497 648
1 209 862
Totals
Table 1. Industrial catches (in tonnes) of major species in each country in 1997, except where indicated
otherwise. Assumed zero catches in parenthesis. Data for
Angola from IIP. Data for
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Namibia and South Africa from Stuttaford (1998).
4.1 Purse-seine fisheries
Annual landings of the major species exploited in the purse seine fisheries of the
region from the 1950s to the present are shown in Figs. 6, 7 and 8 for Angola,
Namibia and South Africa respectively. They are discussed by species below.
350
300
250
Horse mackerel
Sardinella
200
150
100
50
1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995
Fig. 6 Purse-seine catches of sardinella (Sardinella maderensis and S.
aurita
combined) and (predominantly) juvenile Cunene horse mackerel off
Angola since 1956
1 400
Sardine
1 200
1 000
800
600
400
Anchov y
200
Horse mackerel
1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998
Fig. 7 Purse-seine catches of sardine, anchovy and juvenile Cape horse
mackerel off Namibia since 1950
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600
Anchov y
500
400
Sardine
300
Horse mackerel
200
100
Round herring
1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998
Fig. 8 Purse- seine catches of sardine, anchovy, round herring and Cape
horse mackerel off South Africa since 1950
Sardine
Industrial catches of sardine in Angolan waters from the 1950s to the present,
which are reduced to meal and oil, have fluctuated widely from almost zero to a
maximum of 146 000 tonnes in 1957, depending on the state of the Namibian
stock and the degree to which it has extended into Angolan waters. The fish were
initially caught by a large local fleet of small vessels, but after Independence in
1975 were mainly taken by larger, foreign-owned purse-seiners which began
fishing on sardine and sardinellas off Angola in 1976, processing their catches to
a large extent at sea. Since 1994, when the adundance of sardine in Namibian
waters has been particularly low, a number of Namibian vessels have fished
under license for sardine in southern Angola, but only in 1995, when 47 000
tonnes were caught by such vessels, have these catches been significant.
In Namibia, annual catches of sardine (mainly adult fish, taken for both canning
and reduction to meal and oil) rose rapidly from levels of around 200 000 tonnes
to a maximum of nearly 1.4 million tonnes in 1968, whereafter there was a sharp
decline to below 300 000 tonnes in 1971, followed by a slight increase in catches
for a few years and a precipitous collapse in 1977 and 1978. Since then, annual
catches have rarely exceeded 50 000 tonnes, reaching an all-time low of a little
over 1 000 tonnes in 1996. It is most likely that these collapses were largely due
to over-fishing (especially in the late 1960's when in addition to the Walvis Bay
fleet there were two factory vessels operating outside territorial waters), perhaps
exacerbated by a number of years of poor recruitment as a result of adverse
environmental conditions. A change from sardine nets to anchovy nets in the late
1960s, which would have placed greater pressure on the recruits, may also have
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been a contributing factor. With the decline of the stock in the 1970s the fishery
moved increasingly northwards, and the fleet changed from small, predominantly
wooden-hulled vessels to larger steel-hulled refrigerated-seawater vessels
capable of returning the fish from northern Namibia in a condition suitable for
canning.
South African catches of adult sardine for canning, and of both adults and
juveniles for fishmeal and oil, rose from around 100 000 tonnes per annum in the
early 1950s to a peak of around 400 000 tonnes per annum in the early 1960s.
Thereafter, catches declined sharply to well below 100 000 tonnes per annum, a
level which has only recently been regained with the steady growth of the stock
since the mid-1980s. Prior to the collapse, the fishery was based on large adults
off St Helena Bay, caught predominantly in winter. Thereafter it shifted to
younger adults farther south, caught throughout most of the year, and recruits
close inshore on the West Coast in autumn and winter as a by-catch in the
anchovy fishery, a pattern which still persists. The fleet changed from 32-mm
mesh sardine nets to 13 mm anchovy nets in the mid 1960s.
Anchovy
In the 1970s and 1980s, catches of South African and Namibian anchovy, which
were not targeted in South Africa prior to 1964 and were hardly caught in
Namibia before 1966, have been less variable than those of sardine, fluctuating
under quota control around a level of around 300 000 tonnes in South Africa and
200 000 tonnes in Namibia. An exception was the pronounced peak in 1987 and
1988 in South Africa and in 1987 in Namibia, when catches were roughly double
the average. The peak in South Africa is thought to have been due to
exceptionally good recruitment, at least partly associated with enhanced
transport of eggs and larvae to the West Coast in those years, while in Namibia,
the peak was probably caused by an anomalous influx of anchovy recruits from
the Cape stock, driven by the same environmental factors which caused the good
recruitment in the south that year. Annual catches in South Africa in the 1990s
have varied between 40 000 and 347 000 tonnes, but the Namibian catches have
averaged less than 50 000 tonnes per annum during this period, with a decline to
virtually zero in 1996 and 1997. Recent surveys confirm that the anchovy stock in
Namibian waters is severely depleted at present.
Horse mackerels
The purse-seine fishery for predominantly juvenile T. trecae off Angola started in
the 1950s. Catches rose in fluctating fashion from an average of slightly under
100 000 tonnes per annum between 1956 and 1965 to 261 000 tonnes in 1972.
Yields then decreased with the cessation of Portuguese rule in Angola, but a
record catch of at least 380 000 tonnes was recorded in 1978, by which time
distant-water foreign midwater and bottom trawlers, targeting more on adults, had
entered the fishery. In the early 1980s, the proportion of the catch taken by
purse-seine varied between 15 and 47%, the remainder being taken by midwater
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(47 - 76%) and bottom (5 - 18%) trawl. Catches declined sharply during this
period, and by 1984 only 55 000 tonnes of T. trecae in total were landed.
Angolan catches since then have fluctuated between about 25 000 tonnes in
1985 and 1991 and 130 000 tonnes in 1996. A small part of the catch
(approximately 2 000 tonnes in 1997 Anon. 1998a) is taken by small-scale
purse-seiners operating close inshore in what is essentially an artisanal fishery.
In Namibia, horse mackerel were not recorded in purse-seine landings until 1971
when, following the first collapse of the sardine fishery, 140 000 tonnes were
caught. Since then there have been sporadic catches in excess of 100 000
tonnes per year, with an average of 59 000 tonnes and a maximum of 116 000
tonnes in 1992. The fish are utilised entirely for meal and oil.
Purse-seine catches of horse mackerel in South Africa, which were once second
only to sardine in the landings, peaked at 118 000 tonnes in 1954, and thereafter
declined steadily to the early 1970s. Since then horse mackerel have only been a
minor constituent of the pelagic fishery, with annual catches never having
exceeded 10 000 tonnes. This decline is thought to have been due to a decline in
the parent stock, probably aggravated by increased fishing pressure on the
younger juveniles with the introduction of anchovy nets in the mid-1960s.
Sardinellas
Annual catches of the two sardinella species off Angola by the industrial fishery
up to the mid-1970s fluctuated between about 50 000 and 150 000 tonnes. With
the introduction of the large purse-seiners after Independence, annual catches
rose to around 300 000 tonnes, followed by a steady decline from the mid-1980s
to 1992 when catches stabilised at around 50 000 tonnes per year. In 1994 there
were 36 vessels operating in this fishery, of which 26 were purse-seiners and 10
pelagic trawlers. The catch is used for fishmeal because the fish is too bony for
canning. A small amount of sardinella (around 2 000 tonnes in 1997 Anon.
1998a) is also caught by artisanal fishermen in small-scale purse- seine
operations close inshore for local sale and consumption.
Round herring
Round herring have been a minor constituent of the South African purse-seine
fishery since the late 1950s with annual catches in the 1980s and 1990s running
at a level of about 50 000 tonnes, peaking at 76 000 tonnes in 1995. The
juvenile fish are caught as a by-catch in the fishery for juvenile anchovy and
sardine inshore on the West Coast, and the adults in targeted fishing between
Cape Columbine and Cape Point, somewhat farther offshore, particularly during
the first three months of the year. There have also been sporadic attempts to
exploit the large adults in the Algoa Bay region by both purse-seine and midwater
trawl. Some of the catch has been canned and the rest reduced to meal. The
round herring resource in South African waters is believed to be under-utilised at
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present, and attempts at greater exploitation have been encouraged. In Namibia,
around 1 000 tonnes of juvenile round herring are usually taken each year by the
purse-seine fleet for reduction, although catches as high as 14 000 tonnes (in
1996) have been recorded. The potential for canning the larger fish has been
investigated, but they have generally been found to be too soft for this purpose.
4.2 Trawl fisheries
Hakes
Annual catches of Cape hakes (M. capensis and M. paradoxus combined) in
Namibian and South African waters by local and foreign fleets since 1950 are
shown in Fig. 9. Although the demersal fishery began around the turn of the
century, catches prior to 1950 seldom exceeded 50 000 tonnes per annum, with
most fishing effort being in South African waters. The Namibian fishery started in
the late 1950s. In the early 1960s there was an explosive increase in effort and
landings throughout the Benguela, with the arrival of foreign trawling fleets, and
by 1972, the annual hake catch in the south-east Atlantic exceeded 1.1 million
tonnes. Subsequently, catch rates and landings of hake declined sharply, and
conservation measures were introduced, including the declaration of a 200-mile
fishing zone by South Africa in 1977. Since then hake catches in South African
waters have remained relatively stable at just over 140 000 tonnes per year. Off
Namibia, hake catches between 1973 and Independence in 1990 averaged 500
600 000 tonnes annually, mainly taken by foreign fleets. At Independence, strict
conservation measures were introduced, including the exclusion of foreign
vessels. The hake catch is now taken exclusively by Namibian-registered vessels
and the annual local catch has risen from 55 000 tonnes at Independence to
around 120 000 tonnes over the period 1996 1998. Catches of M. capensis and
Namibia
800
600
400
Namibia
Foreign
200
South Af rica
600
400
200
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Foreign
South Af rican
195052 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98
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M. polli in Angola are of a lower order, amounting to less than 1 000 tons per
year in recent years.s
Fig. 9 Catches of hakes off Namibia and South Africa by foreign and local
fleets since 1950
Horse mackerels
Adult horse mackerel are the main target for midwater trawlers operating in
Namibia and Angola, the Namibian fishery being the largest by volume in that
country. Trawl catches of the two species rose from under 50 000 tonnes per
annum in the early 1960s (when horse mackerel were only trawled in Namibia),
to between 600 000 and 700 000 tonnes per annum from 1982 to 1984 (Fig. 10),
by which time most of the catch was being taken by foreign (mainly former Soviet
bloc) vessels. The fish were largely frozen and shipped back to Europe for
human consumption. Trawl catches of horse mackerel (mainly T. trachurus
capensis) in Namibia since Independence in 1990, when Namibia took control of
the fishery, have fluctuated around 350 000 tonnes per annum, with a decline to
between 200 000 and 250 000 tonnes per annum in recent years. The number
of midwater trawlers in the fishery now is less than half that at Independence.
The fleet is largely made up of ageing ex-Soviet bloc vessels, about half of which
are now registered in Namibia, but which are mostly operated by foreign crew.
The major part of the catch is frozen and transhipped to reefer vessels for export
as a relatively low-value product to West Africa, but a small amount is now being
smoked or dried-salted ashore for export to African countries.
Total
600
500
400
Midwater
300
200
Purse seine
100
1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997
Fig. 10 Catches of (predominantly) Cape horse mackerel by midwater
trawl
and purse-seine off Namibia since 1961
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Purse-seine and trawl catches of Cunene horse mackerel in Angola were
summarised in Section 4.1. Compared to these catches, which have generally
been between 50 000 and 100 00 tonnes per annum over the past decade,
catches of Cape horse mackerel in Angolan waters in the past decade have been
insignificant.
The fishery for T. trachurus capensis in South Africa changed from a purse-seine
operation for juveniles on the West Coast in the 1950s and early 1960s to a
bottom-trawl fishery for adults on the South Coast thereafter, caught by both local
and foreign (mainly Japanese) trawlers. Catches rose from about 10 000 tonnes
in 1964 to a peak of nearly 100 000 tonnes in 1978 (Fig.11), and have averaged
about 30 000 tonnes per annum over the past two decades. Between 1967 and
1975, horse mackerel contributed some 40% of the landings of the inshore
demersal fishery on the South Coast, but since the gradual phasing out of the
foreign fishery from 1982, this proportion has declined to around 20%. In the
1990s a targeted midwater trawl fishery for horse mackerel developed, mostly on
the Eastern Agulhas Bank. Catches have been relatively low (average just under
8 000 tonnes per annum between 1990 and 1997) due to operational and
marketing constraints, but there is concern that this fishery has the potential to
threaten the resource. Horse mackerel catches in bottom trawls on the West
Coast in the past decade have never exceeded 5 000 tonnes per year.
Trawl (south coast)
100
Purse-seine (west coast)
80
60
40
20
1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995
Fig. 11 Cape horse mackerel catches in the South African purse-seine
(West
coast) and trawl (South Coast) fisheries since 1950
Monkfish
The Namibian monkfish fishery was initially a by-catch fishery, but in recent years
it has developed into a target fishery in response to increasing market demand.
At Independence in 1990 the fishery changed from an international to a local
fishery. Since then annual catches (mainly by small wetfish trawlers) have risen
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from 1 500 tonnes (the lowest value in the past decade) to around 10 000 tonnes,
comparable to peak levels reached by the international fishery in the 1980s. The
value of the product is high, making this fishery an important contributor to the
Namibian economy (Olsen 1997). The by-catch of monkfish in the South African
demersal trawl fishery on the West and South Coasts has been relatively
constant over the past two decades, at around 5 000 tonnes per year.
Other trawled species
In Angola, roughly 10 000 tons of demersal fish have been caught annually in
trawls in recent years, mainly dentex spp., croakers (Scianidae), grunters
(Pomadasydiae) and groupers (Serranidae). In Namibia the most important other
species caught in bottom trawls are kingklip and sole, catches of which have
averaged 1 275 and 340 tonnes respectively per year since 1990. The average
combined catch of dentex and jacopever in midwater trawls in Namibia since
1990 is 3 750 tonnes (Boyer et al. 1998). In South Africa the two most important
other trawled species are snoek and kingklip. Between 1990 and 1995 catches of
these two species averaged 10 900 and 2 200 tonnes per year respectively.
Deep-water species
Exploratory fishing for deep-water trawl species, particularly orange roughy,
began in Namibia in 1994. Small catches were made in 1995, but in the following
season over 12 000 tonnes of roughy were caught (by bottom trawl) making this
the second-largest roughy fishery in the world. The alfonsino catch during these
two years was nearly 3 000 tonnes. Indications are that the 1997/98 catch of both
species will be at the same level. At present only four roughy aggregations are
being targeted, although there is some exploratory fishing for further
aggregations. Five vessels are currently operating, in joint ventures between
foreign and Namibian companies. The roughy and alfonsino catch is entirely
exported, mainly in the form of high-value frozen fillets for the USA and Japanese
markets respectively.
4.3 Crustacean fisheries
West Coast rock lobster
There has been a fishery for West Coast rock lobster since the early part of the
century, and for a long period the fishery was the world's largest for any Jasus
species. During the 1940s and 1950s South African catches were relatively
stable at around 9 000 tonnes (whole mass) per annum, but from the mid 1960s
to the present catch levels have declined under quota control to around 1 500
tonnes per annum, with particularly sharp declines in the late 1960s, early 1980s
and early 1990s, the most recent one being attributed at least in part to a sharp
decline in the growth rate of individuals. In Namibia, where the resource was
clearly over-exploited, annual catches have declined even more dramatically,
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from a peak of nearly 9 000 tonnes in 1966 to about 3 000 tonnes in the early
1970s, to half this level a decade later, and to a few hundred tonnes in recent
years.
Deep-sea red crab
The red crab fishery in Namibia started in 1973. Catches rose to a peak of about
10 000 tonnes in 1983, after which annual landings declined steadily to 2 676
tonnes in 1991, clearly as a result of over-fishing. Catches have fluctuated
around this level since then. In only two of the years since the introduction of
TACs in 1989 has the TAC been reached. The entire catch is taken by Japanese
vessels fishing with traps. Off Angola, a few hundred tonnes of red crab are taken
by trawl each year as a by-catch of the deep-water prawn fishery. Since 1986
there has also been a directed crab fishery by a single Japanese vessel, which
has caught a few thousand tonnes per year on average.
Deep-water Prawns
The deep-water prawn fishery off the west coast of southern Africa (mainly for
rose and striped prawns) began in 1966, when a single Spanish trawler started
operating off Angola. By 1972, a fleet of 54 foreign (mainly Spanish) trawlers was
operating off Angola, and catches had risen from about 1 000 tonnes per annum
to over 8 000 tonnes per annum. The catch peaked at over 12 000 tonnes in
1973, whereafter there was a sharp reduction in Spanish operations, ending in
complete withdrawal from the fishery by 1977. The Spanish fleet was replaced by
a Cuban fleet, which continued to fish until 1979, the total catch peaking at 11
400 tonnes in 1975. Since then catches have declined, with annual landings of
the two species combined over the past decade fluctuating between about 3
500 and 7 000 tonnes per year (Fig. 12) peaking in 1997. In all but two of the
years, landings of rose prawn have been higher than those of the striped prawn.
At present, there are 44 vessels in the fishery, of which 22 are fishing under an
agreement with the European Union, and the remainder are national.
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Fig. 12 Annual landings of deep-water rose prawn and striped prawn in
Angola since 1988 (from Sardinha) 1998)
4.4 Commercial linefisheries
The total annual catch of tuna in Angolan waters between 1993 and 1995
reported to ICCAT varied between 291 and 910 tonnes, with yellowfin tuna
(caught by local baitboats and longliners) and big-eye tuna (caught by foreign
longliners) making up most of the catch .
Foreign longliners caught tuna in Namibian waters under South African licence
prior to Independence in 1990. The Namibian-controlled tuna fishery started in
1991, and since then an average of 2 330 tonnes of tuna (predominantly
southern albacore) have been taken per year by a fleet of about 30 local and
foreign-owned pole or line vessels. The foreign longline tuna fishery, which
targets bigeye tuna for the high-value sashimi market, started in 1993. Catches
have varied between 52 tonnes in 1996 and 1 005 tonnes in 1994. Experimental
catches of swordfish Xiphias gladius taken by surface longlining have been low
(50 tonnes in three years), but are regarded as encouraging given the low level of
effort. An average of 770 tonnes of snoek has been taken per year by
commercial vessels since Independence, mostly by handline (Boyer et al. 1998).
Catches of silver kob from commercial linefish vessels have fluctuated over the
past three decades around an average of about 500 tonnes per year. It is
estimated that at present the recreational catch of silver kob is roughly equal to
the commercial catch (Kirchner 1998).
The commercial linefishery in South Africa developed rapidly after the Second
World War, reaching its peak in the late 1960s, when about 20 000 tonnes on
average were caught per year. Thereafter, catches declined despite increasing
effort. The average annual catch of all species excluding tuna between 1993 and
1997 was 11 700 tonnes, of which just over half was caught west of Cape Point.
Snoek have consistently contributed over half the catch since the start of the
fishery. The average catch over the past five years was 6 650 tonnes, of which
more than half was landed at St Helena Bay and Yzerfontein on the West Coast.
The second-most important species in terms of landings was hake, with average
landings of just under 1 000 tonnes per annum, caught mostly on the South
Coast. Other important species include yellowtail Seriola lalandi, kob spp.
(particularly Argyrosomus inordus) and geelbek Atractoscion aequidens, which
together contribute almost as much as snoek to the annual landings.
There is a large and varied recreational fishery for linefish species in South
African waters, particularly on the South and East Coasts. Off the West Coast,
the species most commonly taken from boats are tuna, snoek and yellowtail,
while galjoen, hottentot, silver kob and white stumpnose Rhabdosargus globiceps
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are the bony fish most commonly caught by shore-anglers.
The baitboat (pole) fishery for tuna in South African waters started in 1980, and
by 1990 about 10 000 tonnes of tuna (predominantly southern albacore) were
being caught per year. Catches subsequently declined to about half this (6 571
tonnes on average between 1993 and 1997), but reached about 8 000 tonnes
again in 1998. For the past two decades there has also been a longline fishery
for large bigeye and yellowfin tuna by Japanese and Taiwanese vessels fishing
under license, catches of the latter species being confined to the warmer waters
east of Cape Point. In 1997, experimental pelagic longline permits were issued to
South African fishermen, primarily to target high-grade tuna for fresh export. The
vessels have made good tuna catches along the edge of the continental shelf,
and have also caught substantial quantities of swordfish (probably nearly 1000
tonnes in 1998), which has a high market value and is likely to be exploited more
heavily in the next few years.
4.5 Artisanal/subsistence fisheries
By far the most important artisanal fisheries in the region are in Angola, where
they contribute some 30% of the total landings of fish and shellfish. Declared
landings from this sector in 1997 amounted to nearly 30 000 tonnes (Anon.
1998a). In 1995 there were more than 23 000 registered artisanal fishermen,
landing their catches at some 105 controlled landing places, predominantly in the
central provinces of Luanda, Benguela and Kwanza Sul (Delgado and Kingombo
1998). The total number of boats in 1995 was estimated at 4 677, ranging in size
and sophistication from unmotorised canoes (about 25% of the total) to small
wooden boats 5 - 6.5 m long with or without motors ("chatas"), which make up
about 70% of the total, to 8 12 m vessels ("catrongas") with inboard motors and
some preservation facilities (Delgado and Kingombo 1998). Larger "traineiras" (8
25m semi-industrial deckboats with inboard engines) are also involved in small-
scale fisheries along the coast. The most common fishing gears are gillnets,
longlines, and beach- and boat-operated seine nets and traps. The main species
caught are pelagic fish such as sardine and sardinellas, horse mackerel, mullet,
bigeye grunter and small tuna, and demersal fish such as bigeye dentex,
croakers and groupers. Fresh fish is sold in urban areas close to the landing
sites, or because of a lack of freezing facilities, is dried or smoked for sale in the
rural areas.
Artisanal/subsistence fisheries off the West Coast of South Africa (particularly for
mullet Liza richardsoni, which is now caught mainly by beach-seine and
driftnets), have been in existence for centuries, but are of negligible value
compared to the nation's major industrial fisheries. In Namibia there is virtually no
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artisanal/subsistence fishing, because of the uninhabited desert coastline.
4.6 Recreational fisheries
Marine recreational fishing from skiboats and larger gamefishing boats, and by
rock-and-surf anglers and spearfishermen is an important leisure activity in South
Africa, and directly or indirectly generates a significant amount of employment
and revenue (see Section 7). The sector has grown rapidly since the Second
World War, to the extent that surveys indicate that approximately 15% of coastal
residents now fish in the sea on a regular basis. As the fishery has grown, there
has been a tendency along the entire coast for catch rates to decline, and for
endemic inshore reef species (such as galjoen and white stumpnose in the
Western Cape) to be replaced by cartilaginous fish in the rock-and-surf catches.
Recreational fishing in Namibia is pursued by rock-and-surf anglers, who have
access to about 20% of the coastline, and skiboat fishermen operating from
Walvis Bay, Swakopmund and Lüderitz. The sector has grown rapidly in recent
years, and now attracts many visitors to the coast, particularly from Namibia and
South Africa, generating considerable employment and revenue in the coastal
towns (see Section 7). With the recent increase in fishing pressure, the number
of fish caught per angler has declined significantly.
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5. CHANGES IN ABUNDANCE AND DISTRIBUTION OF MAJOR
RESOURCES
5.1 Pelagic resources
Sardine and anchovy
Virtual Population Analysis (VPA) estimates of sardine biomass in Namibia
between 1952 and 1988 (Fig. 13) confirm the marked decline of the stock in the
second half of the 1960s, and the collapse to well below 1 million tonnes in the
mid 1970s. Catch patterns have clearly indicated a northward shift in the core
distribution since the collapse of the fishery in the 1970s, possibly as a result of
the depletion of the southern spawning population and the cessation of
associated migrations. Acoustic survey estimates of sardine on the
Namibian/southern Angolan shelf since 1990 (Fig. 14) indicate that the adult
stock is still well below pre-collapse levels, with an all-time lowest estimate of
only a few thousand tonnes in the summer of 1995/1996, co-incident with the
Benguela Niño at that time (Section 6.1). The surveys also indicated a further
northward shift in distribution in 1994, when the majority of the biomass was
found off southern Angola. Survey estimates of anchovy and juvenile round
herring combined (they are not distinguished in the surveys) have dropped from
levels of around 200 000 tonnes between 1990 and 1993 to below 100 000
tonnes since then. The decline is reflected in the anchovy landings, which have
12
10
8
6
4
2
1945
50
55
60
65
70
75
80
85
90
95
been negligible since 1996.
Fig. 13 VPA estimates of sardine biomass in Namibian waters from 1952
to
1988 (from Boyer 1996)
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Angola
700
Namibia
600
*
*
*
500
*
*
*
400
*
300
200 *
100
*
*
SURVEY YEAR (months)
Fig. 14 Estimates of sardine biomass in Namibia/southern Angola since
1990,
obtained from acoustic surveys (updated from Boyer 1996).
* = Angola not surveyed.
In South Africa, acoustic surveys of sardine over the past 14 years have revealed
a gradual increase in spawner biomass from below 50 000 tonnes in 1984 to
around 600 000 tonnes at present (Fig. 15). The same surveys (supported by
concomitant egg-production surveys between 1983 and 1990) have revealed two
major peaks in anchovy spawner biomass in South African waters during this
period, with pronounced troughs in 1989/1990 and in 1996 (Fig. 15). Acoustic
surveys of sardine and anchovy recruitment off South Africa show the same
general pattern (Fig. 16), except in 1995, when strong anchovy recruitment was
not matched by a high spawning biomass in that or the previous year. Of
particular note is the high degree of correlation between the sardine and anchovy
recruitment estimates throughout the time-series, which suggests that, in South
Africa at least, recruitment of these two species is controlled largely by common
1 500
Anchov y
1 000
500
Sardine
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
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environmental influences on the early life history stages, and not primarily by
spawning biomass.
Fig. 15 Acoustic estimates of anchovy and sardine spawner biomass off South
Africa since 1984 (from Barange et al. in press)
The South African surveys have also revealed significant shifts in sardine and
anchovy distribution in the Southern Benguela since the early 1980s, the most
prominent of which was a sudden large increase in the number of anchovy
spawners on the West Coast in 1986, followed by a progressive reduction to the
more normal low levels over the next three years (Hampton 1992). A significant
eastward shift in both the anchovy and the sardine spawning populations has
also been recorded in the past decade, from 1990 in the case of anchovy, and
from 1988 onwards for sardine (Barange et al. in press).
120
Anchov y
Recruits
100
500.000
Biomass
80
400.000
60
300.000
40
200.000
20
100.000
Sardine
30
Recruits
250.000
25
Biomass
200.000
20
150.000
15
100.000
10
5
50.000
1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
Fig. 16 Acoustic estimates of the number and biomass of anchovy and
sardine
recruits off South Africa since 1995 (from Barange et al. in press)
Sardinella
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Dr Fridtjof Nansen acoustic survey estimates of the biomass of sardinella (S.
aurita and S. maderensis combined) in Angolan waters between 1984 and 1997
are shown in Fig. 17, which suggests that sardinella biomass has increased from
600
500
Sardinella
400
300
200
100
SURVEY
levels of around 200 000 tonnes in the 1980s to more than double this in the
1990s. (This increase was probably at least partly due to the withdrawal of a
major part of the distant-water foreign fleet in the late 1980s). It should be noted
that at least some of the survey estimates are possibly negatively biased
because of the difficulty in assessing sardinella acoustically when the fish are on
or close to the surface, which frequently occurs.
Fig. 17 Estimates of sardinella (S. maderensis and S. aurita) biomass in
Angola
since 1985, from Dr Fridtjof Nansen acoustic surveys (Data from
IIP)
Round herring
According to acoustic survey data, round herring spawner biomass in South
Africa appears to have remained relatively constant at around 1 million tonnes
since the first estimate was made in 1986. No pronounced shifts in the
distribution of adults have been noted from the survey data, although since the
surveys have not always encompassed the distributional range of the population,
the possibility of such shifts cannot be excluded.
5.2 Trawled species
Hakes
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Survey estimates of M. capensis and M. paradoxus abundance off South Africa
and Namibia over the past decade, derived from swept-area demersal surveys
(supplemented by acoustic estimates of fish above the trawl in the Namibian
surveys), are shown in Fig. 18. It is notable that there has been a marked
increase in the abundance of M. paradoxus off Namibia since 1992, which is
confirmed by a marked increase in the proportion of M. paradoxus in the
Namibian hake catches in recent years (E. Voges, NatMIRC, pers. comm.). This
increase may indicate northward displacement or expansion of the stock from
South Africa, or alternatively, a shoreward displacement in response to changes
in the oxygen content of bottom waters. Fig. 16 indicates that in Namibia, the
component of the population targeted by the fishery (i.e. M. capensis >35 cm
long) grew between Independence in 1990 and 1992, but thereafter declined for
the next four years. The most recent survey results indicate exceptionally good
recruitment in 1997 (Boyer et al. 1998), with a subsequent increase in fishable
biomass to the highest level since Independence. Off South Africa, the survey
results suggest an increase in M. paradoxus biomass on the West Coast over the
past decade, but no clear trend in the biomass of M. capensis. The low estimate
for M. paradoxus in 1992 supports the hypothesis of a longshore displacement of
the Cape stock into Namibian waters in that year, but given the uncertainty in the
estimates, this apparent connection should be viewed with caution.
1200 South Africa
Namibia
800
400
M. capensis
M. paradoxus
< 35 cm
Fig. 18 Research survey estimates of the biomass of Cape hakes (Merluccius
capensis
and M. paradoxus) off the West Coast of South Africa and off Namibia
(data from M&CM and NatMIRC respectively)
Fig. 19 (from Anon. 1998b) shows trends in exploitable and total biomass of hake
on the West Coast of South Africa from 1917 to the present, estimated from an
age-structured production model. All indications are that the stock has been
relatively stable over the past two decades, with signs of a gradual increase in
recent years.
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2 000
Exploitable biomass
Total biomass
1 600
Catch
1 200
800
400
1927
1937
1947
1957
1967
1977
1987
Fig. 19 Estimates of the exploitable and total biomass of Cape hakes in South
African waters since 1917 from an age-structured production model
(from Anon. 1998b)
Horse mackerel
Acoustic estimates of horse mackerel (mainly T. trecae) biomass in Angolan
waters between 1985 and 1997, obtained from Dr Fridtjof Nansen surveys, are
shown in Fig. 20. There appear to be two distinct periods: from 1985 to about
1995, when T. trecae biomass fluctuated around a level of about 200 000 tonnes
and capensis biomass was occasionally of the same order, and from 1995 to the
present, when T. trecae levels have been about twice as high, and T. t. capensis
biomass very low. In all surveys the abundance was highest in central and
southern Angola, except in 1996 (a year of anomalously warm conditions along
the whole Angolan coast) when a third of the biomass was found in the north,
between Luanda and Cabinda. The level of these estimates compared to the
catches made at the height of the Angolan horse mackerel fishery (over 380 000
tonnes in 1978) is clear indication of the decline of the resource, which is
supported by the more than 10-fold reduction in annual catches which has
occurred since then (Section 4.1).
600
Cunene horse mackerel
500
400
300
200
100
Cape horse mackerel
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SURVEY
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Fig. 20 Acoustic survey estimates of Cunene and Cape horse mackerel
biomass
in Angolan waters since 1985. Data from IIP (NB: check this Fig!)
Using a VPA of catch data from the former Soviet bloc fleet, Vaske et al. (1989)
estimated that the biomass of Trachurus spp. in ICSEAF Divisions 1.3, 1.4 and
1.5 (i.e. between southern Angola and Cape Agulhas) between 1973 and 1987
fluctuated between about 1.5 and 2.3 million tonnes. This estimate must however
be treated with caution because of, inter alia, the unreliability of the age-length
keys used in ageing the fish. Since 1990, the biomass of adults and juveniles
combined off Namibia and southern Angola has been estimated by annual
acoustic surveys, predominantly from Dr Fridtjof Nansen (Fig. 21). The estimates
generally fall between 1 and 2 million tonnes, with a maximum of 2.1 million
tonnes in 1992. In an absolute sense, these estimates are questionable because
of the lack of verification of the target strength expression used. For example,
use of a target strength expression for T. trachurus capensis developed in South
Africa (Barange and Hampton 1994) would lower the estimates by a factor of
approximately 3. Furthermore, some of the differences between the surveys
have been attributed to variations in the proportion of the population which is
acoustically detectable rather than to fluctuations in the biomass (Anon. 1998c)
a problem which has also been experienced in acoustic surveys of horse
mackerel in South Africa (see below).
2 000
1 500
1 000
500
0
SURVEY
Fig. 21 Acoustic survey estimates of (predominantly) Cape horse
mackerel
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biomass in Namibian waters since 1989. Data from NatMIRC
Bottom trawl survey estimates of T. trachurus capensis biomass on the South
African West Coast between 1985 and the present have increased from less than
10 000 tonnes in 1986 to between 50 000 and 300 000 tonnes since 1991.
Equivalent estimates on the South Coast over this period for the 0-200m depth
stratum have fluctuated between 100 000 and 580 000 tonnes, with an average
of about 300 000 tonnes. There is however evidence from acoustic surveys and
other acoustic observations that the South Coast trawl estimates are negatively
biased because of the unavailability of part of the population to the bottom trawl
at certain times and in certain areas (particularly on the outer shelf and over the
shelf-break).
Deep-water fish
From a swept area analysis of commercial catches in 1996 and 1997, Branch
(1996) and Branch and Roberts (1998) estimated the total abundance of orange
roughy on the Namibian shelf at that time at over 200 000 tonnes. No biomass
estimates considered reliable have yet been obtained for alfonsino. An acoustic
survey of the three most important roughy grounds from Dr Fridtjof Nansen in
1997 gave an estimate of 147 000 tonnes after correction for the major sources
of bias. A major difficulty in assessing the total roughy population by either trawl-
based or acoustic methods is the lack of knowledge regarding the proportion of
the population outside the known aggregations.
5.3 Crustaceans
West coast rock lobster
The Schaefer and Fox production models used to estimate the MSY for the
Namibian rock lobster resource (Section 8.4) have given values of 4 300 and 3
100 tonnes respectively for the period 1958 - 1991. If the very variable data from
the 1960s and the TAC-restricted data from the early 1990s are ignored, these
estimates drop to 1 900 and 1 800 tonnes respectively. Recent modeling
estimates put the stock at around 3 000 tonnes at present.
Assessments of the South African rock lobster resource based on conventional
size-based analyses have shown it to be seriously depleted, estimates of
recruitment in recent decades being only some 35% of pristine.
Deep-sea red crab
Photographic surveys of red crab within two approximately 50-km long sections
of the northern Namibian shelf in the early 1980s indicated a biomass of
approximately 5 000 tonnes in the one area and about 2 000 tonnes in the other.
Recent estimates from analytical models (Section 8.4) indicate that the Namibian
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component of the stock has declined from about 40 000 tonnes at that time to
around 10 000 tonnes in the 1990s, which is reflected in the decline in the catch
rate during this period (Section 4.3). In Angola, estimates of 47 6000 tonnes, 91
000 tonnes and 18 000 tonnes have been reported for 1977, 1982 and 1996
respectively (Neto 1997), perhaps indicating a decline of the Angolan stock as
well, which might be expected in view of the fact that this appears to be a single
shared stock, with considerable trans-boundary migrations.
Deep-sea prawns
Estimates of rose prawn and striped prawn abundance off Angola have been
made from Dr Fridtjof Nansen trawl surveys between 1985 and 1997. The
estimates for the two species combined vary between 1 770 tonnes in 1996 and
5 850 tonnes in 1986, divided almost equally between the two species. There
does not appear to have been any major shift in distribution during the survey
period.
5.4 Line-caught species
Judging from commercial handline catches, the abundance of snoek in Namibia
increased some three-fold between 1970 and 1980, probably in response to an
increase in the abundance of prey in the form of juvenile horse mackerel, which
was then the dominant pelagic fish species in the region. This increase was also
reflected in catches of snoek by the international midwater trawl fleet operating
off Namibia at the time, which rose sharply during this period to levels of over 20
000 tonnes per year. Relatively constant catches by commercial linefishermen
and in trawls since Independence suggest that the population is relatively stable
at present, although the trawl catches are now an order of magnitude lower than
in the 1970s and 80s. It is not clear whether the latter reflects a major reduction
in biomass, or is due to a change in distribution and/or fishing strategy.
Commercial catches of other linefish species in Namibia have also not fluctuated
widely since Independence. Kirchner (1998) has recently estimated that the
current exploitable biomass of the most important of these (silver kob) is in the
region of 11 000 tonnes. The estimate was obtained from a Thompson and Bell
yield-per-recruit model, using catch-at-age data for two years. She estimates
that the stock is currently at between 29 and 46 % of its virgin biomass and that
the current fishing mortality is between 0.12 and 0.22 yr-1.
Fluctuations in the abundance of line-caught species in South Africa are evident
from catch-per-unit-effort (CPUE) indices, which for practically all species have
declined over the past few decades, to almost zero in some cases. This is the
case for both resident reef fish and migratory shoaling species. For many of the
latter it has been estimated that spawner biomass/recruit ratios are now below
the recommended critical threshold level of 25% (Penney et al. 1997), with ratios
for important species such as the silver kob being only 3 12% of pristine. As a
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result of stock declines, the distributional ranges of many of these species appear
to have contracted towards the centre of their past distributions, and the
magnitude and extent of their migrations has declined. Of the migratory shoaling
species, snoek and yellowtail are perhaps the only ones considered not to be
overexploited in South African waters, although there have been substantial
fluctuations in abundance and distribution of both species in the past, probably in
response to changes in the abundance and distribution of their pelagic prey.
5.5 Seals and seabirds
The Southern African seal population was heavily overexploited in past centuries
and the breeding colonies around the Cape Peninsula were exterminated soon
after the arrival of European settlers in the 17th century. Subsequently, as a
result of conservation measures applied over many years, and probably the
establishment of new mainland colonies in areas of restricted human access, the
population increased from around 100 000 animals in 1900 to 1.5 to 2 million
animals in the early 1990s, as deduced from aerial surveys of pups and tag-
recapture studies. The Namibian population subsequently declined (probably by
almost a factor of 2) as a result of breeding failure and high pup and adult
mortalities brought about by the effects of the 1994-95 intrusion of warm, low-
oxygen water into northern Namibia (Anon. 1997a). In 1994 and 1995 there was
also a northward shift in distribution, with Cape fur seals being found as far north
as Luanda, feeding on sardinella. Recent information suggests that the
distribution has now returned to normal, and that the population has almost
recovered to previous levels (Geromont et al. in press).
Aerial censuses have shown that between 1956 and 1986, the population of
Cape gannets at the Namibian colonies declined from around 200 000 adults to
only about 50 000, which was probably due to the decline and subsequent
collapse of the Namibian sardine resource during this period. Over the same
period the adult populations at the two colonies off the Westen Cape remained
relatively constant at around 30 000 birds, whereas numbers at Bird island, Algoa
Bay, increased from around 20 000 to approximately 60 000 birds. The surveys
also revealed a substantial decline in the numbers of Cape cormorant, from more
than a million birds in the early 1970s to about 277 000 pairs in the late 1970s,
and only about 120 000 pairs in the mid 1980s. The decline was most severe in
the north. As with the gannet, the population on the South Coast increased as the
West Coast population declined, by a factor of five between 1956 and 1978. The
African penguin population in Southern Africa has been reduced to very low
levels during the last few centuries through prolonged and excessive egg
collection and disruption of their breeding habitats during the guano rush in the
1840s. The most recent estimate of the total population, from an aerial census in
1995, is about 150 000 birds, of which about 40% were found on islands off the
South African West Coast. Even allowing for underestimation owing to
inadequacies of the aerial survey technique, this population is probably at least
an order of magnitude below pre-exploitation levels. As with Cape gannets and
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Cape cormorants, the distribution of penguins has changed over the past three
decades in response to changes in the distribution and relative abundance of
sardine and anchovy (Crawford 1998).
Crawford and Dyer (1995) and Crawford (in press) have shown that the
proportion of sardine and anchovy in the diet of seabird in the southern Benguela
is strongly correlated with acoustic estimates of sardine and anchovy abundance.
An example is shown in Fig. 22, which compares the trends in the diets of
gannets with the acoustic estimates of sardine and anchovy spawner biomass
since the start of the surveys in 1984.
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Sardine
60
Diet
0.6
50
40
0.4
30
20
Biomass
0.2
10
Anchov y
60
Diet
Biomass
1.5
50
40
1
30
20
0.5
10
'78
'80
'82
'84
'86
'88
'90
'92
'94
'96
Fig. 22 Acoustically derived estimates of sardine and anchovy spawner
biomass off South Afica since 1984, compared with the contribution
of these species to the diet of gannets in the region (from Crawford
in press)
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6. EFFECTS OF THE ENVIRONMENT ON DISTRIBUTION AND
ABUNDANCE
Although a number of Benguela resources have clearly been over-exploited in
the past, some of the variations in abundance and distribution which have been
observed are more likely to have been caused by the major perturbations which
have occured in both the northern and the southern Benguela over the past three
decades, and which are summarised in Thematic Report 2. The probable effects
of these perturbations on some of the major resources of the region are
discussed briefly below.
6.1 Pelagic resources
In a recent Principal Components Analysis of satellite SST imagery from the
northern Benguela between 1981 and 1987, Cole and McGlade (1998) identified
three spatial/temporal patterns which characterised the physical dynamics of the
system. They related two of them (the balance between cross-shelf and
longshore SST gradients, and the warming of the central region in relation to
conditions to the north and/or south), to conditions favourable for clupeoid
production in the region. Other, more specific impacts of the environment on
pelagic resources of the region have been observed, as detailed below.
The biomass of sardine in both the northern and the southern Benguela declined
sharply following a system-wide Benguela Niño in 1963, which in the northern
Benguela caused the fish to be concentrated close to Walvis Bay where fishing
pressure was high. The subsequent collapse in the Namibian sardine after 1974
(Fig. 14) followed a protracted but less intense local Benguela Niño between
1972 and 1974, whose effects were probably aggravated by over-fishing. O'Toole
and Shannon (1997) have postulated that the recent decline in Namibian sardine,
which started in 1993, was largely the result of the advection of low-oxygen water
from Angola in 1993 and 1994, aggravated by a major Benguela Niño in 1995,
which also originated off Angola. In March of that year, the Benguela Niño
caused the entire coast from Cabinda to central Namibia to be covered by
anomalously warm water (up to 8 oC above average in places) to a distance of
more than 300 km offshore (Gammelsrød et al. 1998). Observed mortalities of
sardine, horse mackerel and silver kob, and poor recruitment and declining catch
rates of a number of other key resources in Namibia at the time, are further
indications of a broad-scale environmental effect on sardine and other resources
in Namibia at the time. There was also increased fishing pressure on sardine,
caused by a southward displacement of sardine from northern Namibia and
Angola, increasing the availability of these fish to the Walvis Bay fleet. The more
gradual increases in sardine abundance in the southern Benguela since the mid-
1980s, and to a lesser extent in the northern Benguela in the late 1980s, may be
related to the fact that this was a relatively warm period, with no major
environmental perturbations. Although these observations are all highly
speculative, they are suggestive of strong relationships between sardine biomass
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and the environment in both the northern and the southern Benguela which bear
further investigation.
In the case of anchovy, a Benguela Niño in 1984, which followed an extended
cold period on the shelf, seems to have had an adverse effect on the Namibian
resource. As suggested in Section 3.1, the exceptionally good catches in 1987
were probably largely the result of recruitment from the strong year-classes of
1986 and 1987 in the southern Benguela, rather than from a recovery of the
Namibian stock. Following the most recent Benguela Niño in 1995, which came
at the end of a period of low abundance (Fig. 7), the Namibian anchovy resource
appears to have collapsed completely, or perhaps to have been displaced.
In the southern Benguela, the exceptionally good anchovy recruitment in 1986
and 1987 is thought to have been at least partly associated with enhanced
leakage of Agulhas Bank shelf water onto the West Coast, and the increased
influence of westerly winds, which would have resulted in favourable transport
and entrainment of eggs and larvae with minimum offshore advective loss. The
weak anchovy recruitment in 1989 was associated with poor feeding conditions
during the latter part of 1988 in the spawning area over the western Agulhas
Bank, and with less favourable transport to the nursery grounds on the West
Coast. In general, it appears from extensive studies of transport mechanisms,
food availability, wind stress, primary production and other environmental
influences, that in the southern Benguela there is an optimum environmental
window for good anchovy (and probably sardine) recruitment, with too much or
too little wind stress, primary production etc. being detrimental to recruitment
(e.g. Hutchings et al. 1998). Variations in these conditions may explain much of
the observed variation in recruitment (Fig. 16), and hence in spawning biomass,
although there is evidence that other factors such as temperature and feeding
conditions on the spawning ground, the location and duration of the spawning,
and the condition of spawners can also have an effect on recruitment (e.g.
Hutchings et al. 1998, Painting and Korrûbel 1998, Korrûbel et al. 1998, Shannon
1998). The balance of the evidence does however suggest that offshore
advective loss of ichthyoplankton, which is present to some extent in all years, is
probably a major controlling factor in both anchovy and sardine recruitment.
Isolating and ultimately quantifying the most important environmental factors
affecting the recruitment of pelagic fish in the Benguela region is a major
research thrust, both in national research programmes and in
regional/international programmes such as BENEFIT, ENVIFISH and VIBES (see
Section 8.3).
On a larger scale, the meridional distribution of sardine and anchovy in the
Benguela Current may be affected by shifts in the major wind belts across the
African continent. Their distribution might therefore be expected to be connected
to that of sardine and anchovy in the Canary Current, which would also be
affected by such shifts. In contrast, there is some evidence that regime shifts in
the Benguela, and switches between sardine and anchovy dominance (which
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according to scale-deposit studies have a characteristic periodicity of around 50
years), tend to be out of phase with those in the Pacific. It is also notable from a
comparison between Figs 7 and 8 that, over the past two decades, there has not
been a close correspondence between abundance trends in the northern and
southern Benguela for either sardine or anchovy. This could possibly be due to
the major differences in the geographical relation between the spawning and
upwelling areas in the northern and southern Benguela noted in Section 3.1, and
consequent differences in the effect of wind stress on recruitment processes.
6.2 Trawled species
Relatively little is known about the behaviour of Cape hakes in the Benguela
ecosystem, and of their responses to environmental variability and change. Adult
hake are good swimmers, undergo vertical migrations, can tolerate a range of
temperatures, and are particularly well-adapted to low oxygen conditions, the
adults being able to tolerate levels as low as 0.25 ml l-1 . They are therefore well
able to react to unfavourable environments, and being opportunistic feeders,
long-lived and inhabiting a wide area, should be robust to all but major
environmental perturbations. There is some evidence to suggest that low surface
temperatures favour hake recruitment, or at least that the recruits are more
abundant and at higher densities during cool periods, e.g. in 1992 in the case of
M. capensis in Namibia, and in 1987 for M. paradoxus in the southern Benguela.
Also, there has been a clear positive correlation between monthly catch rates and
SST in Namibia in certain years (e.g. 1994 through 1996), although in other years
(e.g. 1993 and 1997) the correlation has been as clearly negative (Boyer et al.
1998). The reasons for these apparent connections are not understood. The
response of hake to hypoxic conditions is of particular interest in Namibia, where
levels over a large part of the shelf can become intolerable even to hake,
possibly causing major shifts in distribution, affecting recruitment strength
(Woodhead et al.1996), and causing increased mortality of juveniles and older
fish if extensive and persistent enough. For example, Hamukuaya et al. (1998)
found that persistent and pronounced hypoxic conditions off central and northern
Namibia in 1994 displaced M. capensis offshore, subjecting them to heavy
mortality from predation by larger hake and trawling. Improving understanding of
the effects of temperature and oxygen fluctuations on the distribution, abundance
and behaviour of hake in the Benguela region is the focus of a number of local,
regional and international research efforts.
Little is known about the reaction of adult horse mackerel to environmental
perturbations in the Benguela, although it is believed that in Namibia, warm-water
intrusions can cause the fish to move closer inshore (Klingelhoeffer 1996). This is
supported by the fact that in Namibia over the past five years, there has been a
clear positive correlation between seasonal trends in CPUE and surface
temperature along the 200m isobath (Boyer et al. 1998), and by historical catch
data, which show that there was a large-scale southward shift in the distribution
of both T. trachurus capensis and T. trecae in the northern Benguela in the late
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1950s/early 1960s, coinciding with the intrusion of warm, highly saline water from
the north. This was followed by a northward movement from the mid 1970s,
following a period of cooling. The effect of the environment on the distribution and
migration of horse mackerel in the Benguela as a whole is an important trans-
boundary question, inter alia for interpreting and comparing survey results in
neighbouring countries.
The possible effect of environmental changes on the deep-water resources of the
region is totally unknown, but it could be substantial. For example, the fact that
orange roughy off Namibia concentrate within a narrow temperature range and
spawn on very specific sites suggests that any significant change in the near-
bottom temperature could have a major impact on the distribution and perhaps
the spawning process, which could severely disrupt the fishery targeting these
sites.
6.3 Crustaceans
There is evidence that the declines in J. lalandii lobster production in Namibia
and South Africa which occurred towards the end of the 1980s were at least
partly environmentally induced. In the southern Benguela, the decline resulted
from reduced growth rates, whereas off Namibia it was attributed to changes in
availability related to oxygen fluctuations in bottom waters, aggravated by over-
fishing. Since there is relatively little longshore migration of rock lobster, and it is
improbable that fishing impacted all areas simultaneously, it seems most likely
that the resource responded to some large-scale change in the environment. In
the south, the decline in growth rates may have been caused by a reduced
biomass of ribbed mussels, or by changes in primary production and a regime
shift in the benthic foodweb.
6.4 Line-caught species
Relationships between linefish species and the environment in the Benguela
have not been formally studied or quantified in any way. As most linefish species
are predators, the effects of environmental perturbations on their distribution and
abundance is likely to be secondary, through more direct effects on the
abundance and distribution of their prey.
6.5 Seals and seabirds
The high mortality and breeding failure of Cape fur seals at all the Namibian
colonies in 1994 and 1995 was accompanied by a drastic deterioration in the
condition of both pups and adults, and was clearly the result of low food
availability over most of their habitat. This is confirmed by the estimates of low
sardine abundance in the period between 1994 and 1996 (Fig. 14). Likewise, the
major reduction in the number of Cape gannets in southern Namibia (particularly
at Ichaboe Island) in the 1960s and 1970s would appear to be related to the
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decline of the Namibian sardine stock during this period, the sharpest decline
occurring in the mid-1970s, coincident with the collapse of the fishery. The
decline of the sardine stock appears to have had a similar, but somewhat less
pronounced, effect on the Cape cormorant population off Namibia.
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7. SOCIO-ECONOMIC IMPORTANCE
Summary data on the economic value of Namibian and South African commercial
fisheries in 1996 and 1997 respectively are set out in Table 2. (The information
available for Angola is less detailed, and cannot be given in this form).
FISHERY
NAMIBIA (1996)
SOUTH AFRICA (1997)
Landed value Wholesale
Landed value
Wholesale
(Million N$)
(processed)
(Million R)
(processed) value
value
(Million R)
(Million N$)
Pelagic
Canned fish
28.3
291.0
Fish meal &
45.8
66.6
oil
3.4
8.4
Bait
26.0
93.9
77.5
366.0
Total
Demersal
Bottom
593.3 *
718.1
406.1 **
1 000.5 **
Midwater
275.1
293.0
Deep-water
94.2
171.1
Longline
22.2
40.0
Total
962.6
1 182.2
428.3
1 040.5
Crustacea
Rock lobster 13.0
20.2
50.9 102.2
Red crab
17.7
17.7
Total
30.7
37.9
50.9
102.2
Line
Tuna
10.3
12.9
Snoek
24.9
48.5
Other
32.7
44.7
Total
13.3
44.7
67.9
106.1
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Total
1 032.6
1 358.7
624.7
1 614.7
Table 2. Value of major industrial fisheries in Namibia and South Africa in 1996
and
1997 respectively. Namibian data from MFMR. South African data
from
Stuttaford (1998). Note: N$1 = R1.
* Includes longline catches
** Includes midwater trawl catches
The following is a more general description of the socio-economic value of the
major fisheries in each of the three countries
Angola
The fisheries sector is very important in Angola, being the third-most important
industry after oil and diamond mining. It provides nearly half of the animal protein
of the country, and is an important source of employment and food to populations
of the coastal regions, where it is often the only source of livelihood for the poorer
population groups. Domestic consumption of fish, which was estimated at 11.1 kg
per person per annum in 1994, is the highest in the region.
According to the results of a survey conducted in 1992, there were at that time
around 30 000 workers directly involved in activities of the fisheries sector, of
which some 18 000 were involved in artisanal fisheries. The remainder were
involved in industrial fisheries and public administration. In addition, it was
estimated that some 5 000 persons (mainly women) were involved in informal
fish trade activities. A more recent report (Delgado and Kingombo 1998) puts the
number of artisanal fishermen a few years later at over 23 000, and the number
of people involved in informal fish trading at between 20 000 and 30 000. Many
artisanal fishermen are not able to make a living solely from fishing, and
supplement their incomes by, for example, agricultural and commercial activities.
At present, roughly half of the revenue from fish and fish products in Angola
comes from exports, which varied in value between US$ 27 million in 1993 and
US$ 46 million in 1995. Prawns are the most important product, making up 48%
of the total revenue from the fishery sector in 1995, for example. The main export
markets are Europe for prawns and demersal fish, African countries for small
pelagic fish including horse mackerel, and Japan for tuna and crab.
Although some of the resources have clearly been overexploited, others are
probably still under-utilised, evidenced by the fact that, in some of the fisheries,
TAC limits have often not been reached, and that total industrial catches before
Independence were typically some three times higher than they are now. This is
partly due to operational constraints stemming from a breakdown in infrastructure
during the civil war, and the socio-political and security situation in the county at
present. With greater political and economic stability, some of these resources
could well contribute more to the Angolan economy than they do at present.
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Namibia
Fisheries is the third-largest sector of the Namibian economy, behind agriculture
and mining, The industrial fishery has generated more than 10% of the GDP in
recent years, producing products to the value of N$ 1 374 million in 1996.
Exports were valued at N$ 1 048 million in that year, making the sector the
second-largest export earner behind mining. It is the second-fastest growing
industry in the Namibian economy (behind tourism) with the value of production
and exports now being some six times greater than at Independence.
The fisheries sector is extremely important in the social economy of Namibia,
particularly in Walvis Bay, which is the major fishing port and where most of the
processing plants are situated. Local employment in the sector grew rapidly after
Independence, with an estimated 6 000 jobs having been created between 1991
and 1994. The integration of Walvis Bay into Namibia in 1994, and the removal of
the uncertainty regarding the port's future, stimulated an influx of investment in
the fishing industry and subsidiary service industries with a further growth in
employment. The number of people directly employed in the fisheries sector in
1996 was about 15 000, of which some 7 500 were fishermen. Of these 43%
were foreigners, mainly in the horse mackerel and tuna fisheries, a proportion
that has decreased from around 66% in 1993. It has been projected that by the
year 2 000, the total number of people employed in the fisheries sector will have
risen to above 20 000, exceeding the original target of 15 000 set in 1992.
The demersal fishery is the most valuable fishery in Namibia. In 1996 the catch
had a landed value of N$ 593 million, and a final value after product beneficiation
of N$ 718 million. About 90% of the catch is either sea-frozen or wetfish hake.
Monkfish make up most of the remainder, with the average landed value of the
catch in recent years amounting to some N$ 70 million per year (Olsen 1997).
Almost the entire demersal catch is exported.
The pelagic fishery is second in importance, canned sardine being the most
valuable product. In recent years the total export earnings from the pelagic
fishery have been around N$ 400 million per annum, except in 1996 when no fish
were canned, causing exports to drop to N$ 91 million. In more normal years,
canned fish, almost all of which is exported to South Africa, make up more than
90% of the export earnings of the fishery, with fishmeal contributing almost all of
the remainder.
The midwater trawl fishery for horse mackerel has contributed some N$ 250
million per year in exports in recent years, mostly in the form of relatively low-
value frozen fish, with minor contributions from fishmeal (around 10% ) and dried-
salted fish (approx. 3 % in 1996). There is little product beneficiation, the export
value of the catch being typically only about 10% above the landed value. Only
about 3 % of the production is consumed domestically.
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The deep-water fishery has made a significant contibution to the fisheries sector
in recent years, with exports to the value of N$ 171 million in 1996. Orange
roughy contributes more than 90% by value, and alfonsino most of the
remainder. Processing (mainly the production of high-quality fillets for the USA
and Japanese markets) approximately doubles the value of the catch, and is
labour-intensive, providing much-needed employment in Walvis Bay.
The above four industries contribute more than 90 % by product value of all of
Namibia's industrial fish production. Of the remainder, only the tuna (3%), crab
(1.5%) and rock lobster fisheries (1.5%) contribute more than 1% in most years.
To these must be added the recreational linefishery. Kirchner, Sakko and Barnes
(in press) have estimated that between October 1997 and September 1998,
some 8 800 anglers spent 173 000 days angling, and had direct expenditures of
N$ 29.7 million. Value added to gross national income within the shore-angling
fishery during that period was estimated at N$ 14 million. The expenditures
ultimately resulted in gross national income of some N$ 3 000 per angler, or N$
27 million in aggregate.
South Africa
The living marine resources of the Benguela Current form the basis of a fishing
industry which supports some 26 000 people (mostly in the Western Cape), and
supplies food for the whole Southern African subregion. In 1997 the South
African fishing industry caught a total of 445 000 tonnes of fish, shellfish and
seaweed nationwide, of which more than 90% was taken from the Benguela.
The wholesale value of the total processed output in this year was estimated at R
1 953 million, with an export value of R 873 million, on a par with Namibia.
Fishing is particularly important in the social economy of the Western Cape,
where some entire coastal communities depend directly or indirectly on fishing for
their livelihood. However, the fishing industry yields less than 1% of South
Africa's GDP.
In terms of volume, the purse-seine fishery for pelagic species is the most
important sector. In 1997 (a comparatively poor year), landings of pelagic fish
totalled 286 000 tonnes, of which about a third was canned. Practically all of the
remainder was reduced to meal. Because of the high local demand for fishmeal,
and the comparatively small output of canned fish, the pelagic sector exports
relatively little (export value R 31 million in 1996). The sector is entirely
industrialised, the smaller vessels (some of which are privately owned)
concentrating on anchovy and juvenile sardine for meal, and the larger, factory-
owned vessels on adult sardine for canning.
Economically, the trawl fishery is the most important sector of the South African
fishing industry. Catches of hake, which amounted to 147 000 tonnes in 1997,
usually contribute about 70% of the trawl catch and about 80% of its value. Horse
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mackerel, snoek, monkfish and kingklip are the most valuable other trawled
species, together accounting on average for about 20% by landing and value of
the catch. In 1997 the landed value of processed products from a total demersal
trawl catch of 200 000 tonnes was R 428 million. The value of hake exports in
1997 exceeded R 300 million; about a third of the total revenue from all South
African fish and shellfish exports. The fish are largely caught by trawlers
operating under quotas held by a number of large companies, although in recent
years a number of smaller companies and private boat-owners have entered the
trawl fishery. A longline fishery from smaller vessels has also been developing,
accounting for about 3% of the hake catch in 1997.
The West Coast rock lobster fishery is a major export fishery in South Africa,
about 75% of the catch being exported. In the 1997 season, 1 726 tonnes of rock
lobster were landed from the West Coast, with a wholesale processed (mainly
frozen tails) value of R 102 million. The rock lobster fishery is labour-intensive,
and is an important source of employment and income in many fishing villages on
the Cape West Coast.
The wholesale processed value of all commercial landings of linefish in South
African waters in 1997 was estimated at R 106 million, of which about half was
contributed by snoek. Contributions from tuna catches in this year made up 12%
of the remainder. These figures do not represent the substantial direct and
indirect contribution which recreational and subsistence fishing on linefish
species makes to the South African economy. A recent nationwide survey
conducted between 1994 and 1996 (Brouwer et al. 1997, McGrath et al. 1997)
showed that over that period there were some 3 000 registered commercial
linefish boats and about 7 900 skiboats operating off the South African coastline.
About 18 100 crew were employed on the commercial boats, while nearly 14 000
recreational fishermen went to sea on skiboats. They estimated furthermore that
roughly 412 000 people participated in shore-based angling, and about 7 000
each in beach-seining/gill- netting (largely a subsistence fishery) and recreational
spearfishing. In all, they estimated that South Africa's linefisheries and direct
support industries provide employment to over 130 000 people, and that some 20
000 households living in poverty depend on linefish catches for about 9% of their
household income. They put the total contribution of linefisheries to the gross
geographic product (GGP) of South African coastal provinces (Western and
Northern Cape, Eastern Cape and KwaZulu-Natal) at nearly R2 200 million,
which amounts to 1.3% of the GGP of those provinces. Although a significant
proportion of this was caught on the South and East Coasts, it is clear that the
value of the South African linefisheries in the Benguela system is out of all
proportion to the product value of the catch.
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8. MANAGEMENT
8.1 Policy and legal framework
In all three countries of the region it is the national policy to utilise living marine
resources on a sustainable basis for the benefit of the nation, and to manage
them according to scientific information and principles. Ultimate responsiblity for
control measures rests with the State in all three countries. Most of the primary
research on fisheries resources has been done by state-run research institutes
operating within Government Departments (viz. the Ministry of Fisheries in
Angola, the Ministry of Fisheries and Marine Resources in Namibia, and the
Department of Environmental Affairs and Tourism in South Africa).
Angola
The nation's marine and inland fisheries are managed and developed in terms of
the Fisheries Act, which was developed with the assistance of the FAO and
promulgated in 1992. The Act covers such aspects as fisheries management
(which is implemented through various Executive Decrees governing different
sectors of the fishery), planning and licensing, the control of the quality and
export of fish products, and surveillance and enforcement. In recent years, with
the move to a market economy in Angola, and the privatisation of large State-
owned companies, the State has limited its activities to the management of the
resources, surveillance, support of development and the creation of
infrastructure.
The broad national policy regarding fisheries development centres around the
stengthening of regulatory and management capabilities of the Government, the
development of small-scale fisheries, developing and increasing the participation
of the national fleet in industrial fisheries, the rehabilitation of land-based
industries with an emphasis on frozen, salted and canned products, and the
improvement of the quality and distribution of fish for domestic and export
markets. In terms of this Policy, the State is encouraging conversion of present
licencing agreements for foreign fishing into joint ventures involving local vessels
and Angolan entrepeneurs.
Research is carried out by IIP, the Instituto de Investigação Pesqueira (Institute
of Fisheries Research), and IPA, the Instituto de Desenvolvimento Pesca
Artesanal (Institute for Development of Artisanal Fisheries), both of which fall
under the Ministry of Fisheries and have headquarters in Luanda, with smaller
regional laboratories along the coast. IIP annually submits a document on the
current state of the fisheries resources in the Angolan EEZ and
recommendations on TACs and other control measures to the Ministry of
Fisheries, and maintains a corps of some 120 observers for monitoring catches.
As part of the national surveillance system, Angola is already implementing a
VMS for fishing vessels, which is one of the more advanced in the region.
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(CHECK_FONTES)
The Ministry of Fisheries receives support for research and development from
donor agencies such as the Swedish International Development Agency (SIDA)
and the Norwegian Agency for Development Co-operation (NORAD), and from
fishing agreements with the European Union (EU). Cooperation with international
bodies (such as the FAO) and various donor agencies and overseas laboratories
(such as the Institute for Marine Research in Bergen and the Portuguese Institute
of Marine Research in Lisbon) in the development and management of Angola's
fisheries is seen as very important. The development of links with other countries
in the region (particularly Namibia) is also regarded as important, as is
participation in regional marine science programmes such as BENEFIT (see
Section 8.3), whose training and infrastructure-building goals are seen as being
particularly pertinent to the needs of the country.
Namibia
In Namibia, a 200 nautical mile Exclusive Economic Zone was declared on
Independence in 1990, followed by the promulgation of a new Sea Fisheries Act
in 1992, and the introduction of a new national policy on exploitation rights and
quota allocation in 1993. A major emphasis has been placed on Namibianization
of all sectors of the fishing industry and the building up of local research and
management capacity. Fisheries research is conducted within the Directorate of
Resource Management of the Ministry of Fisheries and Marine Resources
(MFMR), by the National Marine Information and Research Centre (NatMIRC) in
Swakopmund and the Lüderitz Research Centre. Scientific recommendations for
the harvesting of all resources except seals are presented to the Namibian Sea
Fishery Advisory Council, which makes recommendations to the Minister of
Fisheries and Marine Resources after considering socio-economic factors and
the industry's perception of the state of the resource. The Council also advises
on the allocation of a research fund derived from levies on catches. The Minister,
after consultation with a Fisheries Management Committee within the Ministry,
submits TAC recommendations to Cabinet for final endorsement. Legislation is
effectively implemented. All fish must be off-loaded under inspection at either
Walvis Bay or Lüderitz, and a fisheries observer trained in basic biological
sampling accompanies all vessels large enough to carry extra personnel.
Surveillance is carried out by patrol vessels and aircraft, and a satellite vessel-
monitoring system is being investigated. In addition to her national
responsibilities, Namibia has established a SADC Sector Coordinating Unit within
the MFMR to discharge her responsibility as Sector Coordinator for Marine
Fisheries and Resources for the SADC.
South Africa
Until very recently, management of South Africa's living marine resources was
carried out in terms of the Sea Fisheries Act of 1988. TACs and other control
measures were decided upon by the responsible Minister (most recently the
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Minister of Environmental Affairs and Tourism), acting on advice from his
Department and a Sea Fisheries Advisory Committee (SFAC), which received
input inter alia from the Department's Chief Directorate of Sea Fisheries. The
SFAC also made recommendations on the allocation of the Sea Fishery Fund, a
fund derived from levies on fish catches that was used to support research and
development activities. Quotas were awarded by an independent Quota Board.
A new Act (the Marine Living Resources Act of 1998) has recently been
promulgated. It includes in its objectives the achievement of broad and
accountable participation in decision-making processes, and the restructuring of
the fishing industry to redress historical imbalances and achieve equity within the
industry. The SFAC has been replaced by a Consultative Advisory Forum (CAF),
which is responsible for advising the Minister of Environmental Affairs and
Tourism on management and development of the fishing industry (including the
setting of TACs), research direction and allocation of a Marine Living Resources
Fund, which replaces the former Sea Fishery Fund. The new Fund receives
income from levies, licences, penalties and other sources, which permits its
disbursement to spheres of fisheries management (e.g. administration,
compliance) other than only research and development. The Minister is
ultimately responsible for deciding upon TACs and other control measures, and
for allocating quotas on advice from his Department. Implementation of fisheries
regulations is still carried out by the Department, with assistance where
necessary from the South African Navy and the Police Unit for Coastal Patrols. A
VMS system to assist in monitoring the movements and activities of fishing
vessels is currently being tested.
8.2 Research and management capacity
Local institutions
In Angola, accommodation available for marine science and technology is
generally adequate, particularly at IIP headquarters in Luanda. However, the
laboratories are not well equipped, and the support infrastructure (technical
services, communications systems, computing and library facilities etc.) is
inadequate to service the needs of the Institute. The Institute's research vessel
Goa is poorly equipped and is at present not operational, making the Institute
totally reliant on foreign research vessels (particularly Dr Fridtjof Nansen) for
research cruises in Angolan waters. Although the Institute employs a number of
research staff with post-graduate degrees in marine science from overseas
universities, most are graduates of the Agostino Neto University in Luanda,
where no courses in marine science subjects are provided. Consequently there is
an acute shortage of professional knowledge, both in terms of numbers and
skills, which is only being partly overcome by post-graduate training within the
Institute and abroad. The same is true of technical support personnel.
NatMIRC in Swakopmund, Namibia, currently employs a research staff of some
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42 scientists, technicians and assistants, and the Lüderitz Research Centre,
which is responsible for research on local resources in southern Namibia, about
10. NatMIRC's office, laboratory, library and meeting facilities are new and
excellent, and the Lüderitz facilities are even newer. NatMIRC possesses a range
of reasonably modern equipment, and there is a public aquarium within the
building to increase public awareness of marine issues. The Ministry operates a
47 - m research stern trawler R. V. Welwitschia (scientific capacity 9) which is
relatively new and well-equipped for resource and environmental surveys in local
waters. All acoustic surveys on pelagic fish are now done on this vessel, but trawl
surveys are still done on Dr Fridtjof Nansen and commercial trawlers because of
limitations in Welwitschia's bottom-trawling capability. The Ministry's scientific
staff are generally well qualified, but have limited experience. On appointment
few have specific training as marine scientists, and most undergo further training
through studying for post-graduate degrees at South African or overseas
universities and the attendance of courses and specialist workshops locally or
abroad. Training and research support is also received from donors and from
foreign consultants attached to or engaged by the Ministry for varying periods.
Nonetheless, there are staff limitations, a particular practical one being the
shortage of qualified technicians to maintain and develop the specialised
equipment needed for research.
Namibian institutions which are involved in marine science education, or which
have the potential to become involved, are the University of Namibia (UNAM) in
Windhoek, through a new course in natural resources which includes marine
science subjects, and the Polytechnic of Namibia, through its nature conservation
diploma. Through the BENEFIT Training Programme, inter alia, ways are being
sought to strengthen the ties between NatMIRC and these institutions and other
tertiary education bodies in the region.
In South Africa, statutory responsibility for advising on the state and management
of marine living resources, and for carrying out the necessary research in order to
do so, resides with the Department of Environmental Affairs and Tourism.
Research was until very recently carried out by the Sea Fisheries Research
Institute (SFRI) in Cape Town, which resorted under the Department's Chief
Directorate of Sea Fisheries. The Institute had an establishment of some 150
scientific and technical staff, who conducted research on all aspects of marine
science, including resource assessment, physical, chemical and biological
oceanography and equipment and gear development (including electronics). The
Institute itself, as well as the Chief Directorate it served, has now been
restructured to meet new challenges in resource management in the country. The
scientific component is now split among three resource-orientated directorates
within a new Chief Directorate of Marine and Coastal Management (M&CM), the
scientific establishment becoming more involved in resource management issues
in an attempt to strengthen the whole Chief Directorate where it is needed most.
Scientists will still however have leading roles in the new structure, within a
matrix-like system which is being developed to ensure continuation of the strong
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scientific ethic already in place.
M&CM has a number of research vessels, the largest of which are the two
research stern-trawlers, R. S. Africana (78m, with a capacity for 19 scientists)
and the 52m-long R. S. Algoa, which has a capacity for 13 scientists. Both
vessels are excellent platforms for multi-disciplinary research, and are relatively
well equipped, although some of the equipment requires updating or
replacement. In recent years the vessels have been underutilised due to staffing
and funding problems, and maintenance problems are increasing. M&CM has
good workshop and library facilities, and possesses a wide range of
oceanographic and survey equipment (some of which was developed in-house),
as well as a newly-built research aquarium of world-class standard. The
Department also publishes the prestigious South African Journal of Marine
Science, edited by M&CM staff, which has a high current ranking in the
international Science Citation Index, and in which much of the research work in
the Benguela has been published. To date 20 volumes have been published,
dating back to 1983.
Other South African institutions actively involved in research in the Benguela are
the University of Cape Town (Departments of Oceanography, Zoology, Applied
Mathematics and Statistical Sciences), the University of the Western Cape
(Departments of Zoology and Botany), and to a lesser extent, the South African
Museum in Cape Town (Taxonomy), the University of Port Elizabeth
(Departments of Zoology and Oceanography), Rhodes University in
Grahamstown (Department of Ichthyology and Fisheries Science), the Port
Elizabeth Museum and the J.L.B. Smith Institute of Ichthyology in Grahamstown,
a national facility of the National Research Foundation. Technical training in
oceanography is offered by the Cape Technikon in Cape Town, which runs a 3-
year diploma in oceanography, with practical training and lecturing by M&CM
staff. These institutions have been an important source of professional and
technical staff for South African marine research institutions, and strong links
have been developed between them and the State, for example through the
Benguela Ecology Programme (BEP); a highly successful collaborative research
venture between the former SFRI and several of the universities (particularly
UCT) which was started in 1981 and is still running (see assessment by Field,
1996).
In South Africa, a national oceanographic data base for physical and chemical
data is maintained by the CSIR's (Council for Scientific and Industrial Research)
South African Data Centre for Oceanography (SADCO) in Stellenbosch. High-
resolution raw and partly-processed thermal and ocean colour imagery can be
purchased from the CSIR's Satellite Applications Centre (SAC) in
Haartebeeshoek, which maintains an archive of NOAA AVHRR imagery dating
back to 1984. These Centres are capable of serving the needs of much of the
region, although there are inadequacies such as incomplete satellite cover of
northern Angola and the lack of biological information within SADCO.
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Donor assistance
Marine research in the Benguela has been, and continues to be, supported by
donations and other assistance from foreign governments such as Norway,
Germany, Iceland, Sweden, Denmark, France, the United Kingdom, Spain and
Japan, plus the European Union. Assistance is also being received from
international organisations such as the FAO.
Through the Nansen Programme, sponsored by the Norwegian Agency for
Development Co-operation (NORAD), the research vessel Dr Fridtjof Nansen has
been active in the South-East Atlantic since her commissioning in 1994, and is to
remain in the region until at least 2002 to assist in the national programmes of
Namibia and Angola, and the regional BENEFIT Programme. Dr Fridtjof Nansen
is a 57-m multi-purpose vessel excellently equipped for stock assessment
surveys and studies on fishing gear performance and fish behaviour. She
replaces her predecessor of the same name which carried out stock assessment
and environmental surveys in Namibian waters from Independence in 1990, and
off Angola since 1985, in terms of an earlier phase of the Programme. The new
phase, which was launched in 1993, places greater emphasis on training and
capacity-building in fisheries research and management, and has recently been
expanded to include the strengthening of local fisheries institutions, particularly in
Namibia and Angola. With the transition to democratic rule in South Africa in
1994, the Nansen Programme established links with marine research institutions
there (particularly Sea Fisheries, now M&CM), and has endeavoured to
strengthen regional co-operation in fisheries research in the Benguela. In line
with this, the Nansen Programme has actively supported the BENEFIT initiative
since its conception, and is now a major provider of financial and material support
to BENEFIT, the latter in the form of ship's time on Dr Fridtjof Nansen and
assistance from Norwegian scientists on the staff of the Institute for Marine
Research (IMR), Bergen.
The German government, through GTZ, the Deutsche Gesellschaft für
Technische Zusammenarbeit (German Organisation for Technical Co-operation)
has supported marine environmental research and monitoring and training in
Namibia since 1993, and has also been an active supporter of the BENEFIT
Programme throughout its development stages. It has recently committed funds
to support BENEFIT in a number of ways over the next three years, including the
funding of a number of regional environmental research activities aimed at
improving understanding of the impact of the environment on the major resources
of the region. In addition, the German government has funded a combined
research and training cruise to the region on a chartered vessel (Petyr Kottsov)
as a contribution to BENEFIT, and has promoted collaboration between regional
and German scientists, mainly from the Institüt für Ostseeforschung,
Warnemunde (IOW) and the Centre for Tropical Marine Ecology (ZMT), Bremen;
collaboration which is expected to continue under the umbrella of BENEFIT.
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In Angola, the Swedish and Danish International Development Agencies (SIDA
and DANIDA) have in the past given considerable assistance in building
infrastructure for fisheries research and development, with a particular recent
emphasis on artisanal fisheries, while in Namibia, the Icelandic International
Development Agency (ICEIDA) has provided assistance to the Ministry of
Fisheries and Marine Resources (MFMR), mainly in the operation of Namibian
research vessels and the training of officers and crew. ICEIDA has also
supported the SADC Fisheries Sector Co-ordinating Unit in Windhoek. DIFD, the
Department for International Development of the United Kingdom (formerly ODA,
the Overseas Development Agency), has developed a fisheries information
system for MFMR, and is currently investigating ways of improving the collection
of fisheries statistics in the whole of the Southern African region. The Japanese
government built and donated R. V. Welwitschia to the Namibian government,
and made a small vessel (R. V. Matsuyama Maru) and researchers available for
specific research projects for a two-year period. Namibia has also received
training assistance from a number of countries and donor agencies and the
FAO, the latter in the form of stock assessment courses and advice by expert
consultants. The FAO has also actively supported courses in South Africa.
The French government is currently supporting a bilateral study with South
Africa, aimed at providing new tools and information for the regional assessment
of pelagic fish resources in the Benguela. The project, code-named VIBES
(Variability of exploited pelagic fish resources in the Benguela ecosystem in
relation to Environment and Spatial aspects) involves collaboration between the
French Research Institute for Development Co-operation (formerly ORSTOM,
now IRD), M&CM, UCT and other universities and research institutes in South
Africa and France. It is to be extended and expanded into the region through
affiliation with the BENEFIT Programme.
The region as a whole is also to receive assistance through a three-year
European Union funded international collaborative project on environmentlal
conditions and fluctuations in the distribution of small pelagic fish in the Benguela
(code-named ENVIFISH). The partners are Angola, Namibia, South Africa,
Germany, Norway, Portugal, the United Kingdom, the European Union Joint
Research Centre in Ispra, Italy, and the FAO. ENVIFISH will be closely linked to
both BENEFIT and VIBES.
8.3 International and regional agreements and conventions
FAO Code of Conduct for Responsible Fishing
Angola and Namibia are signatories to this Agreement. South Africa is yet to
sign, but has agreed in the interim to abide by its provisions.
United Nations Convention on the Law of the Sea (UNCLOS) - South East
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Atlantic Fisheries Organisation (SEAFO)
Angola, Namibia and South Africa have all ratified UNCLOS and have voted in
favour of its Convention on Transboundary and Highly Migratory Stocks, and the
United Nations Implementing Agreement (UIA) relating thereto. Subject to that
Agreement, Angola, Namibia and South Africa, along with the United Kingdom
(acting on behalf of its Dependencies; Ascension Island, St. Helena and Tristan
da Cunha), have formulated the South East Atlantic Fisheries Organisation
(SEAFO) for the conservation and management of straddling and High Seas
stocks in the South-east Atlantic. Other parties which have expressed interest in
SEAFO are the European Union, Japan, Norway, Russia, Ukraine and the USA.
Negotiations on this Agreement are far advanced, and will ultimately lead to
regional arrangements for the management of straddling and High Seas stocks in
the region. This is likely to be the first Agreement concluded under the UIA.
International Commission for the Conservation of Atlantic tunas (ICCAT)
Angola and South Africa are both long-standing members of ICCAT and Namibia
is about to join the organisation.
The BENguela Environment Fisheries Interaction and Training (BENEFIT)
Programme
BENEFIT is a regional marine research and training programme involving
Angola, Namibia and South Africa, with financial and other assistance from a
number of Northern Hemisphere countries which have recently been active in
marine research and training in the Benguela region, such as Norway and
Germany, and the African Development Bank. The Programme is aimed at
improving knowledge and understanding of the dynamics of key commercial
stocks in the Benguela (primarily hakes, horse mackerels, small pelagic fish and
crustaceans) and of linkages between environmental processes and stock
dynamics, with the broad objective of improving management of these resources.
BENEFIT has the full support of the Angolan, Namibian and South African
governments, and of SADC, all of which are represented on a Policy Committee
which guides the Programme through a network of Committees and Working
Groups, on each of which all three countries are represented. International
scientific guidance is provided by a Scientific Advisory Panel, on which France,
Germany, Norway, South Africa, USA and the United Kingdom are represented.
BENEFIT has been conceived as a ten-year programme, and will operate in
terms of a locally-developed Science Plan (Shannon and Hampton 1997) which
inter alia identifies the broad scientific and training problems of the participating
countries, and stresses the need for a regional approach to their solution. The
Programme is now underway, and the first research projects (all of which will be
regional in nature) started in 1999 with assistance from the Norwegian and
German governments (through NORAD and GTZ respectively). The specific
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training needs of the region are being identified, and contacts between local
fisheries research organisations and tertiary education establishments are being
strengthened with a view to developing an integrated regional training
programme for BENEFIT. In addition, in mid-1999 the African Development Bank
sponsored a 40-day BENEFIT training cruise in the region on R. S. Africana,
which provided training in marine science to other African countries in addition to
the BENEFIT partners.
It is envisaged that there will be close links between the BENEFIT and BCLME
Programmes which, although differing in emphasis and scope, will be mutually
complementary.
8.4 Management measures for major resources
Pelagic fisheries
In Angola, sardinellas, horse mackerels and sardine have been assessed
acoustically since 1985 from first the original, and then the new Dr Fridtjof
Nansen (see estimates in Figs. 14, 17 and 20). In the absence of reliable catch
statistics for these species, IIP has based management recommendations solely
on trends in the survey estimates. The fisheries are managed by TAC, with no
distinction between the two sardinella or two horse mackerel species. At a recent
international workshop on the management of small pelagic fish in Angola,
Congo and Gabon, attempts were made to estimate MSY for the region's
sardinella and T. trecae stocks using surplus production models for the former
and an age-structured model for the latter. CPUE indices needed in these models
were derived indirectly from the acoustic survey data and information on total
catches. The sardinella models (which were considered to be more reliable than
the horse mackerel model) placed the MSY at more than double the catch in
recent years (around 60 000 tonnes) suggesting that these species are curently
underexploited. In contrast, the horse mackerel model suggested that the current
level of catch of around 60 000 tonnes per annum is approaching the species'
sustainable level. The Workshop emphasised, inter alia, the need for reliable
direct CPUE indices for all the species considered, the collection of fleet and
country-specific length frequency data, and the need for an effective monitoring,
control and surveillance system in Angola and its northern neighbours.
Prior to Independence in 1990, the management of pelagic fish in Namibia
(primarily sardine and anchovy), was based on stock assessments by South
African scientists, derived from CPUE indices, aerial and acoustic surveys and
VPA of commercial catch data, supported by trends in the diets and breeding
success of predators, and in guano production. Since Independence there have
only been TAC restrictions on sardine and, in recent years, juvenile horse
mackerel. Anchovy catches are however restricted somewhat by a closed season
and limits on the by-catch of sardine. Recommendations on the sardine TAC
have been based on acoustic/midwater trawl surveys conducted by first the old,
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then the new Dr Fridtjof Nansen, and the MFMR research vessels Benguela and
Welwitschia. Extensive use is made of fishing vessels as scouts to find shoal
groups and check that fish have not been missed close inshore or outside the
surveyed area. Attempts have also been made by NatMIRC to deduce population
trends in sardine from VPA and length-based cohort analysis of commercial data,
but this work has been severely hampered by the unreliability of the ageing
techniques used and insufficient information on population parameters.
Consequently, the results have not yet been considered in management
recommendations. At present, the recommended TAC for the forthcoming
season is taken as 18 % of the survey estimate at the end of the previous fishing
season, with subsequent adjustments if surveys during the season indicate
unusually high or low recruitment, growth or mortality. This procedure has
enabled management authorities to react to major resource fluctuations but, as
has been emphasised at a recent international workshop on research and
management of the Namibian sardine (Anon. 1997b), there is a pressing need for
more rigorous stock assessment modelling, using all appropriate data, as the
foundation for management decisions.
In South Africa, the most important pelagic resources (i.e sardine, anchovy and
round herring) have been routinely surveyed acoustically since the mid 1980s,
with surveys of recruitment in winter and spawning biomass in summer (e.g.
Hampton 1992, 1996). Between 1984 and 1993, the anchovy spawning biomass
was also estimated annually by egg surveys, using the daily egg-production
method; a method which is now being considered for sardine. The survey
estimates of sardine and anchovy spawning biomass and recruitment strength,
and of the precision of these estimates, are used together with (in the case of
sardine) estimates of the population age structure from commercial data, to
model the risk to the stocks of various harvesting strategies, and hence to
recommend TACs for sardine and anchovy. This process is carried out through a
Pelagic Working Group, with input from Sea Fisheries survey personnel,
modellers from the Department of Applied Mathematics, UCT and M&CM,
environmentalists and, on occasion, the pelagic fishing industry. The current
strategy is to manage the sardine and anchovy fisheries together and
interactively in such a way as to optimise the sardine catches, while heeding the
needs of the anchovy fishermen, who frequently catch juvenile sardine as a by-
catch. There are at present no direct restrictions on the round herring fishery,
because the resource is not thought to be threatened by the comparatively low
levels of catch (typically less than 50 000 tonnes per year from a stock which has
consistently been estimated acoustically at about 1 million tonnes).
Trawl fisheries
Hake off Angola (Merluccius polli and, in the extreme south, M. capensis), have
been investigated in the course of various bottom-trawl surveys conducted by R.
V. Goa between 1970 and 1992, the old and new Dr Fridtjof Nansen between
1984 and the present, and recently, by chartered fishing vessels. As a part of
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these studies, the other major groups of demersal species in Angolan waters
(dentex, croakers and groupers) have also been investigated. In the absence of
reliable fisheries statistics for any of these species in Angolan waters, stock
assessments and TAC recommendations have been based on trends in the
survey estimates using holistic models. With improvement of commercial catch
information, it will be possible to incorporate CPUE data into the analysis.
Separate TACs are set for the two hake species and for different groups of other
demersal fish. Other forms of control include effort limitation, the prohibition of
trawling close to the coast, and minimum size limits.
Between 1975 and 1989, the assessment and management of Namibian hake
stocks was carried out under the auspices of ICSEAF. Various surplus production
models based on catch and effort data from the Soviet and Spanish fleets were
used in the assessments. The fishery was managed by mesh regulations and
limits on the TAC, which was apportioned between nations according to their
historic interest and performance in the fishery. Since Namibia's declaration of
an EEZ in 1990, and the subsequent withdrawal of foreign fleets, the hake TAC
has been based on biomass estimates obtained from Dr Fridtjof Nansen bottom
trawl surveys, in which Norwegian and Namibian staff participate. To these
estimates are added acoustic estimates of hake off the bottom. The surveys
produce estimates of the fishable (> 35 cm) and non-fishable (<35 cm)
components of the population for both M. capensis and M. paradoxus. Trends in
the survey estimates of the adult stock and of recruitment strength are combined
with CPUE indices of trends in the adult stock to recommend annual adjustments
in the TAC. Previously, the recommendation was set at 20% of the estimated
fishable stock, but a new Operational Management Procedure, in which the TAC
is adjusted according to the average change in the survey and CPUE indices for
the previous 5 years (Butterworth and Geromont 1997), has recently been
recommended as an interim measure until the question of whether the survey
estimates can be treated as absolute has been resolved. (Treating them as
absolute indicates that the resource is currently heavily depleted, in conflict with a
number of different production models, which indicate the opposite Anon.
1997c. The discrepancy is resolved if the survey estimates are treated as relative
rather than absolute).
M. capensis and M. paradoxus in South African waters are assessed as one for
management purposes, using commercial data in a locally-developed dynamic
Schaefer-form production model, which since 1989 has included multiple CPUE
series, and is tuned by data from research swept-area surveys using bottom
trawls. Recently, the Fox form of production model has been applied, and
advances made in incorporating age structure for the hake stock on the South
Coast, where the trawl and linefisheries select different age components of the
population (Geromont et al. 1999). The assessments are carried out by M&CM,
with modelling assistance from the Department of Applied Mathematics, UCT.
The group together makes annual TAC recommendations through a Demersal
Working Group, which liaises with the demersal industry when and where
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appropriate. The survey estimates used in the assessments are obtained from
annual swept-area bottom trawl surveys of the West and South Coasts from R. S.
Africana, using pseudo-random depth-stratified sampling. The estimates are
treated as relative because of difficulty in quantifying catchability coefficients.
Research is currently directed at refining the assessments by using Generalised
Linear Models to improve the validity of the CPUE time series, investigating the
effect of wind stress on commercial catch rates, and disaggregating the
commercial catch by species so that a species-specific VPA can be performed.
Since 1984, assessment of Cape and Cunene horse mackerel in Angolan waters
has mainly been done from acoustic surveys conducted by the old and the new
Dr Fridtjof Nansen, most of them as extensions to Namibian surveys. Information
relevant to stock assessment has also been collected during R. V. Goa cruises
between 1972 and 1992, as well as from collaborative resource studies with the
Atlantic Research Institute for Fisheries and Oceanography (ATLANTNIRO) of
the former USSR. As with other commercial species in Angola, catch statistics on
the horse mackerel fishery are inadequate for assessment and management of
the fishery, and TACs (for the two species combined) are based on trends in the
survey estimates .
In Namibia, adult horse mackerel were assessed and managed from 1980 to
1989 according to TACs set by ICSEAF agreements, based on Schaefer and Fox
surplus production models applied to catch data from the international midwater
trawl fishery. No distinction was made between Cape and Cunene horse
mackerel, although the former dominated in the catches. TACs were allocated
between interested nations by ICSEAF in a similar manner to the hake TACs.
Since 1990, when the fishery came under Namibian control, TACs for the
midwater trawl fishery have been based on MFMR recommendations, made
according to trends in acoustic survey estimates, recently supported by length-
based and age-based VPA estimates, obtained using commercial catch data.
The reliability of horse mackerel ageing techniques needs to be substantially
improved before the age-based VPA estimates can be used with greater
confidence.
In South Africa, the lack of a reliable age-structured catch and CPUE data series
has hampered attempts at producing reliable stock assessments of T. trachurus
capensis. A surplus production model, based on CPUE indices, egg-density data
and abundance indices from direct surveys, was used to assess the resource on
the South Coast between 1989 and 1991 and recommend TACs through the
Demersal Working Group. The first TAC (30 000 tonnes) was set in 1990. These
assessments were discontinued in 1991 when withdrawal of the Japanese
vessels terminated the CPUE time series. Since 1993 a Beddington and Cooke-
type yield-per-recruit model, based primarily on bottom-trawl survey estimates
has been used to set a precautionary catch limit. The estimates are obtained
from surveys on Africana which are biased to a highly variable degree because of
spatial and temporal variations in the availability of horse mackerel to bottom
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trawls. To reduce this bias, acoustic techniques are now being introduced to
estimate the portion of the population on the South Coast which is inaccesible to
the bottom trawl (Barange et al. 1998).
Management of the deep-water fisheries off Namibia is based on TAC
recommendations from the Namibian Deep Water Fisheries Working Group to
the Namibian Sea Fishery Advisory Council. The Working Group consists of
MFMR scientists and industry representatives, and receives input from a number
of foreign scientific and industry consultants. For orange roughy, management is
based on a population model which uses acoustic and swept-area survey
estimates of abundance on the three main grounds, and swept-area estimates of
abundance on these grounds from commercial catches throughout the season, to
recommend TACs for each of the grounds. The current policy for the fishery is to
have a fishing-down period at a constant catch, followed by a gradual reduction
in catches to a level likely to provide MSY. No TACs have been recommended
for the Alfonsino fishery because of the low level of catch. This situation will be
reviewed should the annual catch rise above 2 000 tonnes.
The monkfish fishery in Namibia is at present managed by effort control, mesh-
size limits and by-catch penalties on catches of monkfish by hake trawlers, which
in recent years have made up more than 30% of the monkfish catch. Recently
there has been pressure to move to a catch-limited control system.
Crustacean fisheries
West Coast rock lobster resources in Namibia and South Africa are assessed
and managed according to various population models. In Namibia, a Schaefer
surplus production model based on annual catch and effort data is used to
recommend TACs and minimum size limits, with the assumption that the stock at
the start of the time series (1958) was 40% of pristine. Fishing is controlled by
limits on the TAC per area, a prohibited area and closed season, minimum size
and bag limits, and various restrictions on catch methods. Stock assessment-
related research being conducted by MFMR staff in Lüderitz includes
investigation into the effects of migrations on sex ratios, the estimation of growth
rates through tagging studies, and studies on the effect of environmental
conditions (particularly oxygen levels) on CPUE indices.
In South Africa, the J. lalandii resource has been assessed and managed since
1992/93 through a size-based population model which uses data on growth rates,
size structure and sex ratios in catches, CPUE and total landings. Results from a
Fisheries-Independent Monitoring Survey have also been used. The model,
which has been modified and updated a number of times since its inception, is
used to make recommendations on TACs for the commercial fishery, and on a
minimum size limit. The catch is also controlled by a closed season, prohibited
areas, a bag limit and other restrictions on recreational fishermen. Very recently,
a new Operational Management Procedure has been introduced to facilitate TAC
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recommendations. The input data required are the TAC from the previous year,
and three of the indices of resource status (averaged over the three previous
seasons), which were used previously in the size-based model (Anon. 1998b).
The management of deep-sea red crab in Namibia is based on length-based
cohort analysis and prediction models, adapted to fit the growth dynamics of the
species, using growth rates established by tagging (Le Roux 1997). The models
are used to project future stock size as a function of catch, from which TACs are
recommended. The catch is also controlled by limits on minimum size and the
prohibition of fishing inside the 400m isobath. Management of the resource in
Angola is based on CPUE trends and estimates of MSY, using estimates of
natural mortality from a number of different sources. Catches are controlled by
TAC, effort control, prohibition of fishing inside 500m to protect juveniles and
immature females, a minimum size limit and limitation of the crab by-catch in the
prawn fishery.
The deep-water prawn fishery off Angola is managed on the basis of trawl survey
estimates and CPUE trends, which are used in a simplified Beverton and Holt
model to recommend TACs for rose prawn and striped red prawn. Other forms of
control include the prohibition of fishing within certain inshore areas to protect
juveniles, a closed season and effort limitation /reduction.
Linefisheries
There are effectively no restrictions on catches in the large artisanal fishery in
Angola, partly because of the difficulty in enforcing regulations. Consideration
has however been given to protecting the interests of small-scale fishermen by
prohibiting trawling close to the coast, which can severely disrupt small-scale
fishing operations. The issue has not been resolved and remains a source of
conflict between industrial, semi-industrial and artisanal fishermen in Angola.
Management of the tuna fisheries in Angola and South Africa is carried out in line
with ICCAT regulations. Although not yet a member of ICCAT, Namibia is also
following these regulations, and implements effort control over both national and
foreign vessels. The commercial line fishery for snoek and angling species in
Namibia is at present unrestricted, but recreational catches of angling species
are controlled by closed areas and bag limits.
In South Africa there is a comprehensive suite of linefish management
regulations developed by the National Marine Linefish Committee, which was set
up in 1984. These include regulations on the licensing and number of permits for
commercial fishing boats, bag limits by species category for all recreational and
part-time commercial fishermen, closed seasons for certain species, and
minimum size limits for the most important ones. After 1985 the Committee was
superseded by an independent body; the South African Marine Linefish
Management Association (SAMLMA), which has provided advice on
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modifications of the original measures. The new Marine Living Resources Act of
1998 retains most of the past measures, with some changes in the commercial
permit system and the institution of a "Subsistence" fishing category, in which
fishermen are subject to bag limits but permitted to sell their catches.
Recreational fishermen are also now obliged for the first time to obtain an
angling permit, although as before, will not be permitted to sell their catches.
Continuing reduction in the abundance of most linefish species has led to the
development of a holistic mangement protocol for linefish, which is currently
being taken forward.
Seals
The Namibian seal harvest is primarily controlled through limitations on the
annual TAC, with separate allowances for pups and bulls and for the different
colonies. TAC recommendations are based on aerial censuses and estimates of
biological parameters for the population (fecundity rate, mortality of pups and
adults, sex ratios etc.), which are used in a deterministic, age-structured model of
the female component of the population to predict ideal harvesting levels for
maintaining sustainable yields. The total seal harvest in recent years (which has
not always reached the TAC) has varied between 17 000 animals in 1991 and 38
000 animals in 1994, with pups contributing about 80% of the harvest in all years.
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9. RESEARCH GAPS AND THREATS TO MANAGEMENT
There are a number of broad gaps in scientific understanding of the dynamics of
the Benguela Current's marine resources which inhibit rational, optimal
management of these resources in all three countries. The major problems have
been identified in the Draft BENEFIT Science and Implementation Plan (Shannon
and Hampton 1996), and are the focus of a recently-developed framework for
resources research within the Programme (Anon. 1998d). Briefly, they can be
summarised as:
· Inadequate definition of stocks and understanding of factors affecting the
separation and/or interchange between them, especially for stocks which are
shared between countries or move between them, such as hake, horse
mackerel, red crab and, to some degree, certain pelagic fish species. Lack
of this information makes it difficult to manage these resources on a national
basis and is likely to complicate any attempts at regional management.
· Inaccurate or non-existent information on basic biological characteristics such
as growth and natural mortality rates, reproductive characteristics, recruitment
variability and population age structure for most of the harvested species.
These are important input parameters for population dynamics models used
in the region (which are themselves often inadequate). A particular problem
for most species is the inadequacy and lack of validation of ageing
techniques.
· Inadequate absolute estimates of population size and questionable indices of
population trends for most of the exploited species, due to deficiencies in the
methods used to obtain these estimates. Furthermore, few attempts have
been made to assess the accuracy or precision of the estimates, making it
difficult to assess their value.
· The lack of Operational Management Procedures based on population
models for many of the major resources is seen locally as a serious problem,
precluding any meaningful form of risk analysis or quantitative evaluation of
harvesting strategies for these resources. This is a particular problem in
Angola, and to a lesser extent, Namibia.
· Inability to predict the effect of environmental perturbations on resource
dynamics for any species with sufficient confidence for the predictions to be
used quantitatively in resource management.
Those of the above which are trans-boundary problems in resource management
are summarised in Table 3. Included in the Table is an indication of the
immediate and root cause of each of the problems listed. It will be noted that the
root cause of many of the problems is the lack of regional agreements and
structures for research and management of shared resources, and the shortage
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of manpower and funds to undertake trans-boundary surveys and other trans-
boundary research activities.
Issue
Immediate cause
Root cause
Problem
Management
Inadequate
Lack of trans-
Lack of regional agreement(s) and
of
information on
boundary surveys
structures under which trans-
hakes (South
identity of M.
boundary surveys could be
Africa/
capensis and M.
organised. Shortage of funds and
Namibia)
paradoxus stocks in
manpower for surveys
southern Benguela
Inadequate
Lack of
Shortage of funds and manpower
understanding of
ichthyoplankton
for surveys and data analysis. Low
life history
surveys and migration priority given to ichthyoplankton
(spawning areas,
studies in both
work. Lack of structures for
larval dispersal
Namibia and South
organising trans-boundary surveys
patterns, migration
Africa
and collaborative migration studies
of juveniles and
adults etc.)
Questionable
Different survey
Inadequate intercalibration and
comparability of
techniques, sampling
comparison of techniques. Lack of
stock estimates in
gear and ageing
regional structures for
Namibia and South
methods. Different
standardising methods
Africa
interpretations of
commercial catch data
No
unified
Different approaches
Different national exploitation
Operational
to management and
policies and constraints. Lack of
Management
exploit-ation control
structures for regional resource
Procedure
in the two countries,
management. Shortage of
or common
and different level of
modellers, particularly within
exploitation control
modelling skills
NatMIRC
methods
Inadequate
under-
Lack of studies on
Shortage of funds, vessels and staff
standing of effects of interaction between
for appropriate monitoring and
trans-boundary
hake and their
dedicated behavioural studies
environ-mental
environment on
perturbations on
appropriate scales
abundance,
distribution,
behaviour and
production
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Management
Inadequate
Shortage of trans-
Lack of regional agreement(s) and
of horse
knowledge of
boundary surveys,
structures for joint surveys.
mackerels
integrity of T.
particularly in
Shortage of funds and staff for
(Angola/Nami
trachurus capensis
southern Benguela.
surveys. Shortage of skills in
bia/South
stock(s) off west
Limitations of stock
genetics and other stock
Africa)
coast of southern
characterisation
characterisation techniques
Africa
studies
Inadequate
Lack of
Lack of regional agreement(s) and
understand-ing of
ichthyoplankton
structures for trans-boundary
spawning and larval
surveys and migration ichthyoplankton surveys. Shortage
dispersal patterns,
studies throughout the of funds and manpower for data
particularly in
region
collection and analysis
southern Namibia,
and of adult
migration in this
region
Questionable
Different survey
Inadequate intercalibration and
comparability of
techniques, sampling
comparison of techniques. Lack of
stock estimates in
gear and ageing
regional agreement(s) for
South Africa and
methods. Differences
standardising methods, and of
Namibia/Angola
in methods of
funds and manpower for data
collecting and
collection and analysis
interpreting
commercial catch data
Issue
Immediate cause
Root cause
Problem
Management
Inadequate
Lack of studies on
Shortage of funds, vessels and
of horse
understanding of
interaction between
manpower for appropriate
mackerels
effects of large-scale
horse mackerel and
monitoring and dedicated
(cont).
environmental
their environment on behavioural studies
perturbations on
appropriate scales
abundance,
distribution,
behaviour and
production
Management
Inadequate
Shortage of surveys
Lack of regional agreement(s) and
of sardine
information on the
across national
structures under which trans-
(Angola/
degree of mixing
boundaries at
boundary surveys could be
Namibia/South between Namibian
different times of the organised. Shortage of funds and
Africa) and
and South African
year
manpower for surveys
anchovy (
sardine and anchovy
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South
stocks, and on the
Africa/Namibi
extent to which the
a)
Namibian sardine
stock extends into
Angola.
Inadequate
Lack of
Lack of funds and manpower for
understanding of
ichthyoplankton
data collection and analysis
spawning and larval
surveys in southern
dispersal patterns of
Angola and northern
sardine in Namibia
Namibia (in recent
and southern Angola
times), and lack of
studies on sardine
migration in the
northern Benguela
Inadequate
Lack of integrated
Lack of regional agreement(s) and
understanding of
surveys and
structures for setting up such
physical and
environmental
studies. Shortage of funds and
biological factors
studies on pelagic
manpower for surveys and data
affecting the
fish in vicinity of
analysis
penetration of the
national boundary
South African
anchovy stock into
Namibia and the
Namibian sardine
stock into Angola
Management
Inadequate knowledge Lack of trans-
Lack of regional agreement(s) and
of Deep-sea
of migration of stock
boundary surveys at
structures for setting up trans-
red crab
between Namibia and
different times of the boundary surveys. Shortage of
(Angola/Nami
Angola
year. Limited
funds and manpower for surveys
bia)
tagging and other
and tagging studies
migration studies
Questionable
Different survey and Inadequate comparison and
compara-bility of
assessment
standard-isation of techniques.
stock estimates in
techniques
Lack of regional agreement(s) and
Angola and Namibia
structures for promoting
standardisation
Different
management
Lack of common
Lack of regional agreement(s) for
and exploitation
management and
joint management and exploitation
control methods in
harvesting strategy
control
Angola and Namibia
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Table 3. Immediate and root causes of major trans-boundary problems in the
manage-
ment of the region's marine living resources
In addition to these general scientific problems (which are not unique to the
Benguela), there are particular scientific and operational problems and threats to
management in each country, which differ according to the nature of the fisheries
and the economic realities and research and management capacity in each
country.
In Angola, the resources and their environment have been significantly less
studied than elsewhere in the Benguela, and the history of fisheries research is
too short to have provided a long time-series of observations and a strong
scientific foundation for the proper analysis of trends in population size (Neto
1998). There are limited national data for long-term retrospective analyses of
major fluctuations in the marine ecosystem, large deficiencies in the
understanding of fundamental life history characteristics (e.g. stock delineation,
location of spawning grounds, distribution of ichthyoplankton, nursery grounds,
migration patterns) of commercially important stocks, and no population models
which can be used to evaluate management options. Partly because of the large
number of remote landing points, and a small corps of compliance officials, catch
and effort statistics for many of Angola's fisheries tend to be unreliable, making it
difficult to implement even basic management measures. Research capacity is
limited because of the small number of people involved, the lack of appropriate
tertiary education in fisheries science in the country, and the severe
macroeconomic problems in the country resulting from the protracted civil war
and resultant breakdown of services. There is clearly a desperate need in Angola
for education and training in fisheries science and resource management at all
levels, but this can only proceed if there is stability, and basic services and
infrastucture are in place.
In Namibia, there are fairly reliable catch statistics for all of the exploited species,
and control measures are effectively implemented. The greatest general scientific
problem is the development of rigorous methods of assessing sardine, hake and
horse mackerel biomass from survey and other information, and the building of
these assessments into formal, testable management procedures which take
assessment errors into account. In view of the dramatic effects which the major
environmental perturbations of the mid 1990s had on the abundance and
distribution of Namibian resources (particularly sardine and their predators), a
strong need has been perceived to improve understanding of the effects of the
environment on the country's marine resources, particularly with a view to
predicting recruitment and anticipating changes in distribution. The major
operational constraint is a severe shortage of scientific and technical staff within
the Ministry of Fisheries and Marine Resources for the large number of resources
that have to be studied, and the amount of effort necessary merely to maintain
the current level of resource monitoring. The often prolonged absence of staff
attending training courses and studying outside Namibia for higher degrees
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places an additional load on remaining research staff, further reducing the
amount of time available for detailed analysis of results, innovative research and
the publishing of results in the primary literature. Although the opportunities for
local tertiary education in marine science may improve in due course, lessening
the need for distance-education, this problem is likely to persist for some time.
In South Africa, there are long and generally reliable time-series of catch
statistics for the major exploited species, and effective exploitation control
measures for most of them. The major exception is the linefishery, where
attempts to limit effort have so far been ineffective. The problem is being
exacerbated by technological improvements and increased capitalisation in the
sector, and increasing demands on already over-exploited coastal linefish
resources by a rapidly expanding subsistence sector.
Although the scientific basis for fisheries management in South Africa is very
much stronger than elsewhere in the region, there have been a number of
developments which in recent years have weakened national capacity in marine
science, and which threaten to weaken it further. State funding for marine
research, both within statutory organisations and at universities is shrinking, with
a consequent shortage of funds for equipment, running expenses travel and
education. There is a shortage of funds to maintain, man and operate ageing
research vessels, and at present little provision for replacing them. Because of
these factors, increased difficulty is being experienced in maintaining even
routine resource-monitoring cruises essential for recommending TACs, and there
is almost no ships' time available for developmental work and supporting (e.g.
environmental) research. This jeopardises the substantial progress which has
been made in the past two decades in understanding the effect of the
environment on fish resources in the southern Benguela, at a time when the use
of such understanding in fisheries management is being pioneered in the region.
Also, in recent years there has been a weakening of scientific and research
management capacity within the Department of Environment Affairs and Tourism
due to loss of senior staff brought about largely by moves to reduce the size of
the Public Service. The loss of expertise, and in many cases, posts, has added to
the routine commitments of remaining staff, further limiting their opportunities for
undertaking innovative work and otherwise pursuing their scientific careers. The
weakening of state-funded capacity in marine reseach, unless compensated for
by an increase in the marine research done by non-statutory bodies and through
regional and international co-operative programmes, could well lead to a decline
in the quantity and quality of marine science in South Africa.
With the broadening of participation in the fisheries sector under the new Act, and
the increased number of landing sites, monitoring is becoming increasingly
difficult, which is likely to result in a decline in the reliability of data. The pressure
on already hard-pressed staff within the M&CM Chief Directorate brought about
by growing demands on the MCS Unit and new responsibilities to advise on
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quota allocation (previously the function of the Quota Board) is likely to add to
staffing problems in the years ahead.
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10. ACKNOWLEDGEMENTS
We acknowledge generous assistance given by staff at IIP Luanda, NatMIRC,
Swakopmund and M&CM, Cape Town in providing data needed for this Report.
We also thank the Reprographics Section, M&CM, Cape Town for the use of
figures and other artwork from their files. Drs A.I.L.Payne and P. de Barros are
thanked for extensive and helpful comments on an earlier draft of the manuscript,
which led to a number of improvements, and generally tightening of the text.
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11. REFERENCES AND OTHER LITERATURE
During the past decade several thousand scientific publications on the Benguela
ecosystem and its resources have been published in the primary scientific
literature, the majority of them dealing with the southern Benguela. A listing of
these is beyond the scope of this document. Instead, readers are referred to
Crawford et al. (1987) and references therein for a comprehensive summary of
the published work on the major fish and inverterbrate resources of the Benguela
up to that date, and to the book Oceans of Life off Southern Africa (Eds. A.I.L.
Payne and R.J.M. Crawford, 1989, revised in 1995), which gives a popular but
authoritative account of the same body of work. Much of the more recent work
has been published in the South African Journal of Marine Science, particularly in
the three "symposium volumes" viz. Vol. 5: The Benguela and Comparable
Ecosystems (Payne et al. 1987), Vol.12: Benguela Trophic Functioning (Payne et
al. 1992) and Vol. 19: Benguela Dynamics: Impacts of Variability on Shelf-Sea
Environments and their Living Resources (Pillar et al. 1998). A wealth of
information on the Namibian and South African fishing industries, fisheries,
catches, etc. may be found in the Fishing Industry Handbook series, edited by M.
Stuttaford and published annually by Marine Information CC. The references
listed below give details on these publications, a short selection of other useful
works, and the articles cited in the text, which have largely been restricted to
work which has appeared since publication of the BENEFIT Science Plan
(Shannon and Hampton 1996, 1997).
ANON 1997a Proceedings of International Workshop on Research and
Management of
Cape Fur Seals in Namibia, Swakopmund,
June 1997: 60 pp.
ANON 1997b Proceedings of International Workshop on Research and
Management of
Pilchard in Namibia, Swakopmund, February
1997: 130pp.
ANON 1997c Proceedings of International Workshop on Research and
Management of
Hake in Namibian Waters, Swakopmund, October 1997: 233pp.
ANON 1998a Dados estatisticos sobre as capturas da pesca artesanal, 1997.
Instituto de
Desenvolvimento da Pesca Artesanal, Ministério das Pescas,
Luanda,
Angola: 54pp.
ANON 1998b - Research Highlights, 1997-1998. Sea Fisheries Research
Institute, Cape
Town, South Africa: 67pp
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ANON 1998c Cruise Report of Dr Fridtjof Nansen horse mackerel survey, June
1998.
National Marine Information and Research Centre,
Swakopmund.
ANON 1998d Framework BENEFIT Resources Research Programme. July
1998.
BENEFIT Secretariat, Windhoek: 8pp.
ARMSTRONG, M. J. and R. M. THOMAS 1989 - Clupeoids. In Oceans of Life off
Southern
Africa.
Payne, A.I. L. and R. J. M. Crawford (Eds).
Cape Town;
Vlaeberg: 105-121.
BAKUN, A. 1995 Patterns in the Ocean: Ocean Processes and Marine
Population
Dynamics. Published jointly by Centro de
Investigaciones Biologices di
Nord Ovest, La Paz, Mexico and
University of California Sea Grant, San
Diego, USA: 320pp.
BARANGE, M. and I. HAMPTON 1994 Influence of trawling on in situ estimates
of
Cape horse mackerel Trachurus trachurus capensis target
strength. ICES
J.mar.Sci. 51: 121-126.
BARANGE, M., PILLAR, S.C. and I. HAMPTON 1998 Distribution patterns,
stock
size and life-history strategies of Cape horse mackerel
Trachurus
trachurus
capensis,
based on bottom trawl and
acoustic surveys. In
Benguela Dynamics:Impacts of
Variability on Shelf-Sea Environments
and their Living
Resources. Pillar S.C., Moloney, C.L., Payne, A.I.L.
and
F.A.Shillington (Eds). S.Afr.J.mar.Sci. 19: 433-449.
BARANGE, M., HAMPTON, I. and B.A. ROEL (in press) Trends in the
abundance
and distribution of anchovy and sardine on the South
African continental
shelf in the 1990s, deduced from acoustic
surveys. S.Afr.J.mar.Sci. 21:
367-391.
BIANCHI, G. 1992 Demersal assemblages of the continental shelf and upper
slope of
Angola. Mar. Ecol. Prog. Ser. 81: 101-120.
BOYER, D. 1996 Stock dynamics and ecology of pilchard in the northern
Benguela. In
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Upwelling Systems, Swakopmund,
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BOYER, D., BOTES, F., BURMEISTER, L., CLOETE, R., FOSSEN, I.,
HOLTZHAUSEN,
H.,
KIRCHNER, C., KLINGELHOEFFER,
E.,
LETH,
N.,
MAARTENS, L., STAALESEN, B., STABY,
A., and
E.VOGES 1998 Collected papers; First
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Current Large Marine Ecosystem (BCLME) Programme, UNDP,
Cape Town, South Africa, 22-24 July 1998: 14pp.
BRANCH, T.A. 1996 Baseline biomass estimates for orange roughy off
Namibia,
using a swept-area technique. Unpublished
ms. Namibian Deep Water
Fisheries Working Group: 13pp.
BRANCH, T.A. and R.D. ROBERTS 1998. - Swept-area estimates for Namibian
orange
roughy. Namibian Deep Water Fisheries Working
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WG/01/98/DWFWG/ORH:5:
21pp.
BROUWER, S.L., MANN, B. Q., LAMBERTH, S.J., SAUER, W.H.H. and C.
ERASMUS. 1997. A survey of the South African shore
angling fishery.
S.Afr.J.mar.Sci. 18: 165 - 177.
BUTTERWORTH, D.S. and H.F.GEROMONT 1997 Evaluation of a range of
possible simple interim management procedures for the
Namibian hake
fishery. Report to the Ministry of Fisheries and
Marine Resources,
Namibia: 28pp.
COLE, J.F.T. and J. McGLADE 1998 Temporal and spatial patterning of sea
surface
temperature
in
the northern Benguela upwelling
system:
possible
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indicators
of
clupeoid
production. In Benguela Dynamics:
Impacts of Variability on
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(Eds).
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CONSTANÇA, L. J. 1995 An evaluation of the trawl surveys used for
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waters. M. Phil. thesis,
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CRAWFORD, R.J.M. 1998 Responses of African penguins to regime changes
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of
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CRAWFORD, R.J.M. (in press) Seasonal responses to long-term changes of
prey
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to a
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DELGADO, F. and P.A. KINGOMBO 1998 (Effect of) Coastal development and
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FIELD, J.G. 1996 The South African "Benguela Ecology Programme". In
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and larvae
from the western Agulhas Bank to the West Coast
during the 1993/94 and
1994/95 spawning season. In Benguela
Dynamics:Impacts of Variability
on Shelf-Sea Environments and theirLiving Resources. Pillar S.C.,
Moloney, C.L., Payne, A.I.L. and F.A.Shillington (Eds).
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19: 181-195.
GAMMELSRØD, T., BARTHOLOMAE, C.H., BOYER, D.C., FILIPE, V.I.L. and
M.J. O'TOOLE 1998 Intrusion of warm surface water along the
Angolan-Namibian coast in February-March 1995: the 1995
Benguela
Niño. In Benguela Dynamics:Impacts of Variability on
Shelf-Sea
Environments and their Living Resources. Pillar
S.C., Moloney, C.L.,
Payne,
A.I.L. and F.A.Shillington
(Eds). S.Afr.J.mar.Sci. 19: 41-56.
GORDOA, A., MACPHERSON, E. AND M. OLIVAR 1995 Biology and fisheries
of
Namibian hakes (M. paradoxus and M. capensis). In Hake:
Biology, Fisheries
and
Markets. Alheit J. and T. J. Pitcher
(Eds). London;
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GRIFFITHS, M.H. (submitted) Life history of Thyrsites atun (Pisces:
Gempylidae): a
pelagic predator of the Benguela Ecosystem.
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HAMPTON, I. 1992 The role of acoustic surveys in the assessment of pelagic
fish
resources on the South African continental shelf. In
Benguela
Trophic
Functioning.
Payne, A.I.L., Brink, K.H., Mann,
K.H. and R.Hilborn
(Eds). S.Afr.J.mar.Sci. 12: 1031-1050
HAMPTON, I. 1996 Acoustic and egg-production estimates of South African
anchovy
biomass over a decade: comparisons, accuracy and
utility. ICES J. mar.
Sci. 53: 493-500.
HAMUKUAYA, H., O'TOOLE, M.J. and P.M.J. WOODHEAD 1998
Observations of
severe hypoxia and offshore displacement of
Cape hake over the Namibia
shelf in 1994. In Benguela
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their Living Resources. Pillar S.C., Moloney, C.L.,
Payne, A.I.L.
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HUSE, I., HAMUKUAYA, H., BOYER, D.C., MALAN, P.E. and
T.
STRØMME 1998
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their Living Resources. Pillar S.C.,
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HUTCHINGS, L., BARANGE, M., BLOOMER, S.F., BOYD, A.J., CRAWFORD,
R.J.M., HUGGETT, J.A., KERSTAN, M., KORRÛBEL, J.L., DE
OLIVEIRA, J.A.A., PAINTING, S.J., RICHARDSON, A.J.,
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L.J.,
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1998 Multiple factors affecting South African
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GEROMONT, H.F., DE OLIVIERA, J.A.A., JOHNSTON, S.J. and C.L.CUNNING-
HAM (in press) Development and application of management
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KIRCHNER, C. (1998) Population dynamics and stock assessment of the
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silver
kob
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KIRCHNER, C., SAKKO, A.L. and J.I. BARNES (in press) The economic value
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KLINGELHOEFFER, E. 1996 An overview of research on the Namibian horse
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KORRÛBEL, J.L., BLOOMER, S.F., COCHRANE, K.L., HUTCHINGS,
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12. ACRONYMS
ATLANTNIRO Atlantic
Research
Institute for Fisheries and Oceanography
(Kaliningrad, former USSR)
AVHRR
Advanced Very High Resolution Radiometer
BCLME
Benguela Current Large Marine Ecosystem (Programme)
BENEFIT
BENguela Environment Fisheries Interaction & Training
(Programme)
BEP
Benguela
Ecology
Programme
CPUE
Catch Per Unit Effort
CAF
Consultative Advisory Forum (South Africa)
CSIR
Council for Scientific and Industrial Research (South Africa)
DANIDA
Danish International Development Agency
DIFD
Department for International Development (United Kingdom)
EEZ
Exclusive
Economic
Zone
ENVIFISH
Environmental Conditions and Fluctuations in Distribution of
Small Pelagic Fish Stocks (Programme)
EU
European
Union
FAO
(United
Nations)
Food
and Agriculture Organisation
GTZ
Deutsche
Gesellschaft
für Technische Zusammenarbeit
ICCAT
International Commission for Conservation of Atlantic Tunas
ICEIDA
Icelandic International Development Agency
ICSEAF
International Commission for the South-East Atlantic Fisheries
IIP
Instituto
de
Investigação Pesqueira (Angola)
IPA
Instituto
de
Desenvolvimento da Pesca Artesanal (Angola)
IMR
Institute
of
Marine Research (Bergen, Norway)
IOW
Institüt
für
Ostseeforschung (Warnemunde, Germany)
IRD
(French)
Research
Institute for Development
M&CM
(Chief Directorate) Marine and Coastal Management (Department
of Environmental Affairs and Tourism, South Africa)
MFMR
Ministry of Fisheries and Marine Resources (Namibia)
MSC
Monitoring, Surveillance and Control
NatMIRC
National Marine Information and Research Centre (Namibia)
NORAD
Norwegian Agency for Development Co-operation
ODA
Overseas Development Agency (United Kingdom)
ORSTOM
French Research Institute for Development through Co-operation
SADC
Southern African Development Community
SADCO
South African Data Centre for Oceanography
SAC
Satellite
Applications
Centre (CSIR, South Africa)
SAMLMA
South African Marine Linefish Management Association
SEAFO
South East Atlantic Fisheries Organisation
SFAC
Sea Fisheries Advisory Committee (South Africa)
SFRI
Sea Fisheries Research Institute (South Africa)
SIDA
Swedish International Development Agency
SST
Sea
surface
temperature
TAC
Total
Allowable
Catch
UCT
University of Cape Town
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UIA
United Nations Implementing Agreement
UNAM
University of Namibia
UNCLOS
United Nations Convention on the Law of the Sea
VPA
Virtual-population
Analysis
VIBES Variability of exploited pelagic resources in the Benguela ecosystem in relation to
Environmental and Spatial aspects (Programme)
VMS
Vessel
monitoring
system
ZMT
Centre
for
Tropical Marine Ecology, Bremen
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SYNTHESIS AND ASSESSMENT OF INFORMATION ON THE BENGUELA
CURRENT LARGE MARINE ECOSYSTEM (BCLME)
THEMATIC REPORT NO.2
INTEGRATED OVERVIEW OF THE OCEANOGRAPHY AND
ENVIRONMENTAL VARIABILITY OF THE BENGUELA
CURRENT REGION
By
L.V. SHANNON and M.J. O'TOOLE
Windhoek, Namibia November 1999
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1.
INTRODUCTION
The Benguela is one of four major current systems which exist at the eastern boundaries of the world
oceans, and the oceanography of the region is in many respects similar to that of the Humboldt
Current off Peru and Chile, the California Current off the west coast of the U.S.A. and the Canary
Current off north-west Africa. These eastern boundary currents are characterized by upwelling along
the coast of cold nutrient-rich water, and are important centres of plankton production which support
a global reservoir of biodiversity and biomass of fish such as sardine (pilchard), anchovy and horse-
mackerel and also sea birds and marine mammals.
The coastal upwelling area of the Benguela Current ecosystem extends from southern
Angola along the west coast of Namibia and South Africa around the southernmost part of
the continent. While the area shares many of the generic characteristics of other eastern
boundary currents, it is unique in that it is bordered at both northern and southern ends by
warm water systems viz. the Angola Current and Agulhas Current respectively. These
equatorward and poleward boundaries are not fixed in space and in time, but are highly
dynamic, and their pulsing impacts on the ecosystem as a whole and on its harvested
resources. With a western boundary approximating to the 0° meridian, the Benguela thus
encompasses the coastal upwelling regime, the eastern part of the South Atlantic gyre and
a complex system of fronts and transition zones. In terms of the Benguela Current Large
Marine Ecosystem (BCLME) Programme, the Benguela is viewed in a broader context
than is customarily defined, and includes the full extent of Angola's Exclusive Economic
Zone (EEZ), with a northern boundary at 5°S at the Angola Front. (The latter is the
boundary between the BCLME and the equatorial current system.)
The earliest physical observations in the South Atlantic and Indian Oceans were those
necessary for the safe and efficient passage of sailing ships along the trade routes between
Europe and the East. The early Portuguese, Dutch and other navigators accordingly
compiled comprehensive records of winds and currents records which display a
remarkable amount of information about the underlying physical oceanography of the
region. The first published work of scientific merit was, as may be expected, of currents
around the Cape of Good Hope and was compiled by James Rennel in the 18th century
(Rennel 1778). It was, however, the cruise of the H.M.S. Challenger in the 1870s which
initiated the global science of oceanography, and pioneering studies were conducted on
that expedition in the Benguela region during 1873. The next half-century witnessed the
age of the great oceanographic expeditions inter alia those of the Valdivia, the Gauss, the
Planet and the Möwe. It was, however, work undertaken during the expedition of the
German Meteor in the South Atlantic between 1925 and 1927 that resulted in a quantum
jump in human understanding of the oceanography of the Benguela and adjacent regions.
The scene for development of regional oceanography was set by the arrival in Cape Town of
Professor J. D. F. Gilchrist in 1896. Gilchrist is regarded as the father of southern African
oceanography, and he undertook a host of marine studies in Angola, Namibia, South Africa and
Moçambique. During the second half of the twentieth century it was oceanographers such as Drs T.
J. Hart, R. I.Currie, A. J. Clowes, A. H. B. De Decker, N. D. Bang, J. R. E. Lutjeharms and L. Hutchings
who contributed so much to the understanding of the complex physics, chemistry and biology of the
Benguela.
This overview is a brief summary the oceanography and environmental variability of the
Benguela Current Large Marine Ecosystem. As such it draws principally on the published
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scientific literature which now comprises several thousand authoritative articles. In
preparing this overview, we have synthesised available information and ideas and have
attempted, where possible and where appropriate, to simplify and to explain concepts in
such a way that they will be intelligible to non-oceanographers, yet still useful to marine
scientists with an interest in the Benguela system. It is not, however, a Benguela science
review per se: There are a number of authoritative reviews in the international scientific
literature, and these are referred to in the text, together with other key publications.
The overview commences with a discussion of the main physical features and processes in
the Benguela - the bathymetry, windfield, temperature, upwelling, currents, fronts and
boundaries. Key aspects of the chemistry and chemical processes follow, including major
and minor elements and all-important dissolved oxygen. The next section deals with
plankton, primary and secondary production and the foodweb and carbon budget. We have
also devoted several paragraphs to a discussion of environmental variability and the
ecosystem consequences thereof. Finally we have provided a perspective on the various
issues, problems and threats facing the Benguela, and have identified what we believe are
the major gaps in knowledge and understanding. It is hoped that the various sections
collectively will provide a useful introduction to, or at least background information for,
those overviews dealing with more specific aspects of Benguela resources.
2. PHYSICAL FEATURES AND PROCESSES
2.1 Bathymetry
The continental shelf along the west coast of southern Africa is variable in width and
depth. It is narrow off southern Angola (20km), south of Lüderitz (75km) and off the Cape
Peninsula (40km) and widest off the Orange River (180km) and in the extreme south
where the Agulhas Bank extends over 200km polewards from Cape Agulhas, the
southernmost tip of Africa. The edge of the continental shelf, or shelf break as it is
generally termed, lies at depths between about 200m and 500m. The position of the 200m
depth contour (isobath) is shown in Fig. 1. By global standards the Benguela continental
shelf is relatively deep, and the slope and configuration of the shelf is by no means
uniform. Indeed, double shelf breaks are common off the west coast of Southern Africa:
for example near Walvis Bay (23°S latitude) there are inner and outer breaks beginning at
depths of about 140m and 400m respectively. This is illustrated graphically in Fig. 6,
which also shows a similar feature at 32°S off South Africa. Between about 31°S and 35°S
several convoluted submarine canyons intersect the shelf, the best known of which is the
Cape Canyon which lies approximately 80 north-west of Cape Town. The variable
topography of the Benguela shelf is of particular significance for near shore circulation
and for fisheries.
The continental shelf is covered by layers of sediments primarily of biological origin
(biogenic) and large areas of shelf sediments contain more than 75% calcium carbonate.
Significant features of the Benguela shelf are two extensive mud belts, each about 500km
long. The southern belt extends from the Orange River southwards, up to 40km wide with
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an average thickness of 15m, and is mainly of river origin. The northern belt which lies
over the middle shelf off Namibia comprises organically rich diatomaceous oozes
(originating from planktonic plants). In places the organic carbon content of these
diatomaceous muds exceeds 15%!
West of the shelf break is a steep continental slope area which descends to a depth of
about 5000m where it meets the abyssal plain of the South-east Atlantic Ocean. This plain
comprises two large ocean basins, the Cape Basin and the Angola Basin, separated by a
submarine mountain chain, the Walvis Ridge which runs from its abutment with the
continental shelf at latitude 20°S (northern Namibia) in a south-westerly direction for
more than 2500km towards the Mid-Atlantic Ridge. The steep continental slope and a
cross-section of the Walvis Ridge is illustrated in Fig.6. As may be expected, the latter
feature forms a barrier to deep circulation in the South-east Atlantic. Other prominent
bathymetric features are the Agulhas Ridge which forms the southern boundary of the
Cape Basin, and the Agulhas Plateau both shown in Fig. 1, and numerous seamounts of
volcanic origin, of which Vema is perhaps the best known.
2.2 Winds
Winds significantly influence the oceanography of the Benguela region on various time
and space scales, ranging from basin-wide seasonal and longer period processes to local
inshore events of only a few hours duration. The prevailing winds along the west coast of
southern Africa are controlled by anticlockwise (anticyclonic) motion around the South
Atlantic High pressure system, the seasonal low pressure field over the land and eastward-
moving cyclones which cross the southern part of the subcontinent. The South Atlantic
High (Anticyclone) is part of a discontinuous belt of high pressure which encircles the
southern hemisphere and is maintained throughout the year. Small seasonal differences
occur. On average the anticyclone is centred at about 28°S: 8°E, and undergoes seasonal
shifts, being at a more northerly and easterly position in winter than in summer. The
pressure over the subcontinent alternates between a well-developed low during summer
and a weak high in summer, and consequently the atmospheric pressure gradient and
hence wind is seasonably variable. The coastal plain, much of which is arid, acts as a
thermal barrier to cross-flow, and hence winds tend to be predominantly southerly
(longshore) over most of the Benguela region, being "topographically steered" along the
coast. These longshore winds produce coastal upwelling which gives much of the
Benguela its cool surface water characteristics (discussed in the next subsection).
The essential seasonal differences in the intensity of the upwelling-producing longshore
winds is best illustrated in Fig.2. From this diagram it is evident that the principal
perennial area of strong southerly winds lies near Lüderitz (27°S) with a secondary area
near Cape Frio (18°S). In winter the northward shift in the atmospheric pressure systems
has a strongest influence south of 31°S, where there is a relaxation of the southerly winds
and a greater frequency of westerlies. Off central Namibia wind speeds are generally
lower on average, and display less seasonality. Off northern Namibia, the longshore wind
is strongest during autumn and spring. North of about 15°S, the latitude of Namibe in
southern Angola, the winds are much weaker than off Namibia and South Africa, although
they remain longshore on average and reach maximum intensity during winter.
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A common feature of the wind field during autumn and winter are "Berg" winds. These
catabatic winds occur when there is a pronounced high pressure over the subcontinent, and
they blow down from the central plateau across the escarpment and over the coastal plain
and then seawards. They are hot, dry winds, often laden with fine particles of dust which is
visible in some satellite pictures. They exert little direct physical effect on the sea,
however, as being warm, they tend to blow above the cool marine atmosphere layer.
Apart from seasonal changes in the windfield, coastal winds are modulated in the southern
Benguela during summer by the passage of the easterly-moving cyclones (low pressure
cells) which move past the tip of the subcontinent. These result in periodic changes in
winds from northerly initially with an easterly component, before blowing from the
northwest to southerly (southwesterly to southeasterly). The latter can be quite intense
and are often characterised by a "tablecloth" of cloud over Table Mountain at Cape Town.
These wind relaxation-reversal-strengthening events typically occur on periods of 3 to 10
days.
Diurnal changes in coastal wind intensity and direction are common throughout most of the Benguela
region north of St Helena Bay (near 33°S). These are associated with the differential heating and
cooling of the sea and the adjacent land mass, typical of the classical land-sea breeze effect. Off
much of Namibia coastal fog is often associated with the night time and early morning slacker winds,
and tends to dissipate around noon when the southerly wind intensifies.
Readers wishing to know more about the climatology of southern Africa are referred to a
definitive book on the subject by Tyson (1986), while comprehensive accounts of the
winds over the ocean are contained in Nelson and Hutchings (1983), Shannon (1985), and
Shannon and Nelson (1996). For comparisons of the winds and oceanography between the
Benguela and the other three eastern boundary current systems, Parrish et al (1983) and
Bakun and Nelson (1991) are recommended texts.
2.3 Upwelling and surface temperature
Coastal upwelling is the process whereby cold water is brought to the surface near the
coast under the influence of longshore equatorwards winds. The essential process is
illustrated in Fig. 3. In simple terms, the longshore wind can be viewed as displacing
warm surface water northwards and, as a consequence of the earth's rotation, offshore.
This results in a drop in sea level against the coast, which serves as a non-permeable
boundary. To balance the displaced water, the deeper water wells up inshore, and
compensatory circulations and longshore currents over and adjacent to the continental
shelf are set up. In a simple one cell system, the thermocline (layer where there is a strong
vertical temperature gradient) is displaced vertically upwards, and may result in a front
between the warm oceanic water and the cool upwelled water, with water moving at depth
over the shelf and upwards, and sinking at the front. This is in reality an over-
simplification two or three fronts may develop with rather complex circulations in
between, while the actual extent of upwelling and the intensity and direction of shelf
currents will be influenced by "coastal trapped waves" a type of internal wave within the
ocean. The existence of these coastal trapped waves can result in enhanced or reduced
upwelling and larger sea level changes than might simply be inferred from the wind.
Nevertheless, as a general rule, the areas along the west coast of southern Africa where the
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southerly winds are consistently strongest are also the areas where upwelling is most
pronounced. It follows, therefore, that coastal upwelling in the Benguela is neither uniform
in time or in space.
The wind field, topographic features (bathemetry and land features) and orientation of the
coast result in the formation of a number of areas where upwelling is more intense. The
principal upwelling centre or cell is in the central Benguela in the vicinity of Lüderitz
(27°S). Strong upwelling occurs there throughout the year (Stander, 1964), with some
slackening during autumn, and the extensive zone characterised by cold surface water,
weak stratification and high turbulence which results there appears to be an important
determinant of the biology of the system effectively dividing the Benguela into two
quasi-independent subsystems (Fig. 7). There are several secondary upwelling cells viz
Cunene, northern Namibian and central Namibian cells (at approximately 18°, 20° and
24°S) and the Namaqua, Columbine and Cape Peninsula cells (at about 31°, 33° and
34°S). The last two are seasonal, with maximum upwelling occurring between September
and March, whereas off northern and central Namibia upwelling is more perennial, but
with a late winter maximum. Several smaller ephemeral upwelling cells develop to the
west of headlands along the south coast. Although upwelling does occur along the coast of
Angola at times, it is not pronounced, and the water column remains stratified throughout
the year.
In the northern Benguela peak upwelling and insolation (solar heating) are out of phase,
and sea surface temperatures over the shelf follow a distinct seasonal cycle. In the south
off the Cape Peninsula, maximum insolation and the upwelling season coincide, and
average sea temperatures inshore vary seasonally by little more than 1°C. Viewing the
Benguela in terms of a heat budget, the central zone is a major heat sink, with negative
climatological sea surface temperature anomalies of 5° - 6°C in the Lüderitz vicinity.
South of Africa in the area influenced by the Agulhas Current positive climatological sea
surface temperature anomalies of 2°-4°C exist and the area is a major heat source for the
atmosphere.
Off Angola, north of about 14°S, there is a positive offshore climatological sea surface
temperature anomaly during summer. The dramatic temperature differences between
surface waters of the Angolan and Agulhas Currents and those associated with upwelling
off Namibia and South Africa are illustrated in Figs 4 and 8.
2.4 Water masses and general circulation
Like temperature, salinity is an important physical property of sea water, and also affects
density, and density and pressure (which is approximately proportional to depth) are key
parameters in terms of ocean dynamics just as they are in the atmosphere, the only
difference being that sea water is less compressible than air. Salinity is measured in
"practical salinity units" (psu) and one psu corresponds to one part per thousand or one
tenth of one percent. The salinity of sea water is typically about 3.5% or 35 psu, but like
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temperature can vary. Salinity is influenced inter alia by fresh water input from rivers, by
evaporation, precipitation, freezing of sea water and melting of sea ice.
Water masses are defined by specific temperature-salinity properties. There are a number
of different water masses present off the west and south coasts of southern Africa, and
their distribution and essential characteristics have been described by various authors and
reviewed by Shannon (1985), Chapman and Shannon (1985) and Shannon and Nelson
(1996).
The principal water masses in the Southeast Atlantic are Tropical and Subtropical Surface
Waters, Thermocline Waters (comprising South Atlantic and Indian Ocean Central
Water), Antarctic Intermediate Water (AAIW), North Atlantic Deep Water (NADW) and
Antarctic Bottom Water (AABW). The "core" characteristics of these are annotated in Fig.
5 which shows the typical temperature-salinity curves (relationships) for the water masses
present in the South-east Atlantic. The linear part of the curve (approximately 6°C, 34.5
psu - 16°C, 35.5 psu) spans the Thermocline Water layer, and this is the water which
upwells along the coast, and which constitutes, often in highly modified form, the waters
present over the continental shelf in the Benguela system. From this figure it can be seen
that there are quite marked differences between the Thermocline Water present in the
northern and southern parts of the Benguela and true South Atlantic Thermocline Water.
At the core of the layer, however, i.e. at 10° - 12°C, it is impossible to distinguish between
the Thermocline Waters of different origins on the basis of temperature and salinity only.
The flow of the Thermocline Water tends to be similar to that of the overlying surface
water, which is discussed a little later. In a recent paper Poole and Tomczak (1999) using
optimum multiparameter analysis show a clear separation between Thermocline Water in
the Benguela Current system south of about 25 °S and that further north, the latter being
>80% Western South Atlantic Central Water.
Thermocline Water overlies Antarctic Intermediate Water, which is formed in the
Southern Ocean and which is characterised by the salinity minimum in the temperature-
salinity curve. The core of the AAIW in the Benguela has a salinity in the range of 34.2
34.5 psu and a temperature of 4° - 5°C, and is present in the region at an average depth of
700 800m. In terms of volume, AAIW accounts for about 50% of the water present in
the upper 1500m. The AAIW in the southern Benguela is generally much fresher (younger
and less mixed) than that present off Angola and Namibia, and is also fresher than that
from the Indian Ocean. The differences in "freshness" of AAIW at three areas in the
Benguela is illustrated in Fig. 6. While there is some northward movement evident in the
south of mixed South Atlantic and South Indian AAIW, the greater part of this water mass
in the Benguela region (at least in the area adjacent to the continental shelf) evidently
moves southwards from the tropical South Atlantic, having reached the area by a
somewhat circuitous route. Further offshore, the AAIW flows in a north-westerly
direction. AAIW does not upwell to the surface anywhere in the Benguela.
North Atlantic Deep Water corresponds to the deep salinity maximum (see Fig. 5) and has
a salinity typically >34.8 psu, and lies below the AAIW stratum. As its name suggests it is
formed in the North Atlantic. It then sinks and spreads southwards. At the equator it
comprises a thick layer between 1000m and 3500m of relatively warm (for its depth) and
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saline water. West of the Benguela continental shelf it flows generally polewards,
becoming diluted en route south. Volumetrically, NADW is the main water mass present
in the South-east Atlantic.
Underlying NADW in the Cape Basin is Antarctic Bottom Water. AABW forms near the
edge of the Antarctic continent in the Weddel Sea area, and spreads throughout the
Southern Ocean. Unless prevented by topography, it also tends to spread northwards in the
South Atlantic, Indian and Pacific Oceans. In the Cape Basin it flows slowly clockwise,
moving southwards at depths greater than 4000m west of the Benguela continental shelf.
The Walvis Ridge forms a virtually non-penetrable barrier to the northward flow of the
AABW, which as a consequence is not significantly present in the Angola Basin. The
effect of the Walvis Ridge on the distribution of AABW is dramatically illustrated in Fig.
6.
Whereas the general movement of deeper water masses viz. AAIW, NADW and AABW
in the Southeast Atlantic is polewards, the flow of the Subtropical Surface Water (STSW)
tends to be more closely aligned to the direction of the prevailing wind at least in the
area south of 15°S latitude where the flow is generally in a north-westerly direction with
speeds typically in the range 10 15 cm/s. with an average of around 17 cm/s. As a
consequence of seasonal warming and cooling of surface water, the temperature salinity
characteristics of STSW can be quite variable, and can range from 15° to 23°C and 35.4
psu to 36.0 psu. (see Fig. 5). The surface water present off Angola is mainly of
tropical/equatorial origin. Temperatures in excess of 25°C are common, reaching 28° -
29°C in summer and there is usually a very strong and shallow thermocline present. (This
and the contrast with the area further south is highlighted in Fig. 6.) Surface salinity in the
area is highly variable, ranging from very low values close to the mouths of major rivers
such as the Congo, to levels in excess of 36psu further offshore. The influence of the
Congo River at the surface can be substantial, and water from this source can be traced as
far south as Namibia. (Dr M. E. L. Buys, pers. comm.) It is generally observed as a thin
surface layer, lens-like in places overlying a strongly stratified surface sea water layer.
The principal features of the flow of surface water, and away from the coast also of
Thermocline Water, is illustrated schematically in Fig. 7. The broad arrows between 15°
and 35°S represent the Benguela Current, which can best be defined as the integrated
equatorward flow of the upper layers in the South Atlantic east of the 0° meridian. The
circulation has been described in some detail by Stramma and Peterson (1989) and
summarised by Shannon and Nelson (1996), and readers are referred to these papers for
further particulars. In terms of absolute volume, the total equatorial flow of the Benguela
Current, including that of surface, Thermocline and AAIW is thought to be about 15 25
Sv (one Sv is 106 m3/s). North of 15°S, which encompasses the Angola system, the main
features of the currents within the surface, Thermocline and AAIW layers are (a) a large
cyclonic gyre centred around 12°S, 4°E viz. the Angola Dome (b) the Angola Current
which flows southwards along the edge of the continental shelf and (c) the Equatorial
Undercurrent and South Equatorial Current which feed the Angola Current from the north-
west. The oceanography of the Angola system (including the Angola Dome) and the
offshore northern Benguela area was well documented by Moroshkin et al (1970). The
existence of the Angola Dome and cyclonic flow around it was confirmed by Gordon and
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Bosley (1991). The volume transport around the Angola Dome is of the order of 3 Sv. The
major dynamics affecting the eastern tropical Atlantic Ocean were summarised Voitureiz
and Herbland (1982) and by Picaut (1985).
Of the 15 25 Sv equatorward flow in the main Benguela Current (as defined earlier),
some 7 Sv is of Indian Ocean origin (Van Ballegooyen et al 1994). The latter comes from
the Agulhas Current which flows southwards and westwards along the east coast of South
Africa. The Agulhas Current is the major western boundary current in the Indian Ocean
(75 Sv), and is rather analogous to the Gulf Stream and the Brazil Current. The Agulhas
tends to follow the edge of the continental shelf and on reaching the Agulhas Bank turns
southwards and then eastwards, flowing back into the Indian Ocean. This turning back is
termed "retroflection". Small periodic meanders termed the Natal Pulse, may develop in
the main body of the Agulhas Current off Natal and these grow downstream, resulting in
the Current becoming unstable and the shedding of large eddies or rings. About six or
eight Agulhas rings are shed each year, and these fast spinning rings move slowly
(typically 5 8 cm/s) in a west-north-westerly direction into the South Atlantic,
transporting about 7 SV of Indian Ocean water on average. At the surface shallow
filaments of Agulhas Current water also may round the Cape of Good Hope, just outside
the upwelling area, but the mass of water associated with these filaments is usually fairly
small although occasionally the southern Benguela is flooded by warm water of Agulhas
origin. The retroflection of the Agulhas Current and the leakage of warm Indian Ocean
water into the South Atlantic is well illustrated in Fig. 4, and shown diagrammatically in
Fig. 7.
In summary the main features of the surface currents are:
Offshore: flow of about 15 20 cm/s (i.e. about 1/3 knot in a northwesterly
direction over most of the region between 15°S and 35°S (viz. the Benguela
Current)
Cyclonic circulation around the Angola Dome and periodic intrusion of tropical
water from the north and north west into the northern Benguela
Leakage of Agulhas Current water into the South Atlantic, mainly via rings and to
a lesser extent via shallow filaments
2.5 Shelf circulation
Circulation over the continental shelf and in the oceanic area adjacent to the shelf has been
the subject of intensive investigation during the past twenty years, although most of the
effort has been focussed on the southern Benguela. The various observations were
summarised by Shannon and Nelson (1996) and again recently by Shillington (1998).
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Surface currents over much of the Benguela shelf are largely influenced by the prevailing
winds. In the south there is a general convergent flow of surface water from the Agulhas
Bank westwards and northwards around the Cape of Good Hope which funnels into a
frontal jet west of the Cape Peninsula (discussed later). Typical speeds are in the range of
25 75 cm/s. Near Cape Columbine (33°S) the surface current divides into an offshore
flow and a northward alongshore flow, partially into St Helena Bay. A southward moving
current often occurs near the surface close inshore over the entire region, particularly
during winter and also periodically during the rest of the year when reversals take place on
a time scale of several days. Over the Namibian shelf, the surface currents are generally in
a northerly direction, closely aligned to the wind. However, periodic and episodic
reversals in the surface currents can occur, the most pronounced and extended reversals
occurring during Benguela Niños (discussed in Section 5). The most prominent circulation
feature off the coast of Angola in the southward flowing Angola Current. Whether this
current is a permanent or seasonal feature is not clear as most of the more comprehensive
investigations appear to have been undertaken during the autumn and winter months.
Certainly the existence of the Angola Current was well documented by Moroshkin et al
(1970). It is a coastal current, generally present as a poleward flow over the upper part of
the continental slope (i.e. west of the shelf break), detectable between the surface and a
depth of about 200m. Literature on the current is sparse, but there is some evidence of
seasonality, with the most intense flow occurring during late summer (March), when
surface speeds as high as 70cm/s have been reported, and subsurface speeds of up to 88
cm/s (Dias 1983). The dynamics of the Angola Dome and Angola Current are linked with
those of the system of equatorial currents and the Benguela Current and upwelling
processes. However, to what extent the Angola Current contributes to the Benguela system
off Namibia is uncertain at the surface and subsurface at least. In this respect Dias
(1983) showed that most of the southward flow of the current at a depth of 100m turned
between 16°and 17°S latitude to flow westwards just north of the Angola-Benguela front.
At greater depths e.g. 400m, the poleward flow from Angola into the northern Benguela
does however seem to be more continuous, and this has been the focus of recent
cooperative research between German, Norwegian, Angolan, Namibian and South African
scientists.
In the southern Benguela, in particular off the Cape Peninsula, but also in the vicinity of
Cape Columbine there exists a strong equatorward flowing jet. First predicted and
discovered by Bang and Andrews (1974) the existence of this jet has subsequently been
confirmed as a semi-permanent feature of the upwelling system. Current velocities are
highest at subsurface depths, being typically in the range 25 75 cm/s. The jet is
important biologically in that it is known to transport eggs and larvae of various fish
species from the spawning grounds on the Agulhas Bank to the nursery areas inshore north
of Cape Columbine. To what extent the jet is continuous throughout the Benguela, or
indeed even if it exists in the central and northern Benguela, is not known, although there
is a suggestion in the work of Gordon et al. (1995) that a jet like feature is present in the
upper 100m over the mid-shelf near Lüderitz.
Apart from the shelf-edge jet, the most significant discovery during the past two and a half
decades has been of a poleward undercurrent. The idea of a poleward flow in upwelling
regions seems to have originated from ideas put forward by Hart and Currie (1960) in their
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classic text on the Benguela Current viz. as some form of compensation for the water
displaced from the inner shelf by upwelling. Nelson (1989) showed that, as in the case of
in other upwelling systems, a poleward undercurrent does exist in the Benguela, but which
is much more extensive than that required as compensation for coastal upwelling,
stretching from the coast, across the shelf and out into the Cape Basin. Current meters
have revealed that subtidal currents on the shelf are dominated by the presence of coastal
trapped waves (previously commented on), which have periods of 3 to 8 days. These result
in a net polewards flow of about 5km/d or 5.8 cm/s (Nelson 1989). On occasions this
southwards-moving current may reach the surface inshore, resulting in episodes of
poleward flow at the surface. In St Helena Bay, such events result in episodic flushing of
the Bay. Aspects of the poleward current will be discussed further in Section 3.1 which
addresses dissolved oxygen.
The shelf-circulation can thus be briefly summarised as follows:
Wind driven surface currents over the shelf
Poleward subsurface flow over shelf and in deeper water adjacent to shelf
throughout the region (4-5 km./d)
Poleward flowing Angola Current in extreme northern part of the Benguela region
i.e. along coast of Angola
Jets associated with the upwelling system and located near the edge of the
continental shelf in the southern Benguela
Coastal trapped waves are characteristic of the shelf area throughout the Benguela
(periods typically 3-8 days).
2.6 System boundaries, fronts and filaments
Whereas a thermocline refers to a layer where there is a rapid change in temperature with
depth, a halocline and a pycnaocline are vertical discontinuities of salinity and density
respectively. Fronts refer to areas where there is a sharp change in temperature, salinity (or
some other parameter such as colour) horizontally. Reference back to Fig 3 which
illustrated a simplified concept of upwelling, it can be seen that where the thermocline
intersects with the sea surface, the vertical discontinuity is translated into a horizontal
discontinuity viz. a front. Physical boundaries of, and within, the Benguela are usually
associated with fronts of one form or another, and these fronts tend to form barriers to
horizontal movement of water and small particles such as plankton. They may be less
important as barriers for highly motile animals such as fish and marine mammals.
Northern boundary
The physical northern boundary of coastal upwelling is marked by the Angola-Benguela
frontal zone. The temperature and salinity front (series of fronts) is a permanent feature at
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the surface, identifiable to a depth of at least 200m, and is maintained throughout the year
within a narrow band of latitudes, characteristically between 14°S and 17°S (i.e. close to
the Angola-Namibia border). The front generally has a west-to-east orientation, and
appears to be maintained by a combination of factors, including bathymetry, coastal
orientation, stratification, wind stress and opposing flows of the Benguela and Angola
Currents. The southwards migration of the front is most pronounced during late summer
when longshore winds in the northern Benguela are weaker and upwelling is reduced. The
situation in northern Namibia/southern Angola is in some respects analogous to the
seasonal cycle off Peru in the Pacific during some years, when anomalously warm water
appears (El Niño). There is a South Atlantic equivalent of the Pacific El Niño and it
manifests itself as an episodic extreme warming in the tropical eastern Atlantic and the
movement of tropical water southwards and eastwards along the Namibian coast. These
Benguela Niños (Shannon et al. 1986) occur on average every ten years and are not
necessarily in phase with the El Niño- Southern Oscillation (ENSO) although some links
with the latter are evident. Benguela Niños occurred in 1934, 1949, 1963, 1984 and 1995
and probably also in 1910, in the mid-1920s and in 1972-1974. Although not as frequent
or intense as El Niños, like the Pacific counterpart, their impact on the ecosystem and
harvested resources in the northern Benguela is enormous.
The characteristic location of the Angola-Benguela frontal zone is shown in Fig. 7. This is
a much simplified diagram, as the "front" is often a combination of fronts with convoluted
characteristics. (For example see Fig. 8 which illustrates the surface expression of the
Angola-Benguela frontal zone in April 1997).
While the Angola-Benguela Front (more correctly a series of fronts) comprises the
northern extent of the main coastal upwelling zone, upwelling can occur seasonally along
the entire coast of Angola. There are, in any event, strong linkages between the behaviour
of the Angola-Benguela front (and the oceanography of the area to the south of it) and
processes occurring off Angola, especially the Angola Dome and the Angola Current.
Unless these are considered as an integral part of the BCLME, it will not be feasible to
evolve a sustainable integrated management approach for the Benguela. Moreover, there is
a well-defined front at about 5°S, viz the Angola Front which is apparent at sub-surface
depths. It is this front which is the true boundary between the Benguela part of the South
Atlantic and the tropical/equatorial Gulf of Guinea system. A northern boundary at 5°S
would thus encompass the Angola Dome, the coastal Angola Current and the area in
which the main oxygen minimum forms and the full extent of the upwelling system in the
South-east Atlantic. A pragmatic northern boundary is thus at 5°S latitude (see Fig 7)
which is in the vicinity of the northern boundary of Angola (Cabinda) and the southern
extent of the Gulf of Guinea Large Marine Ecosystem (GOGLME).
Southern boundary
The southern boundary of the Benguela system can be considered as the Agulhas
retroflection area, typically between 36° and 37°S. Like the northern boundary, this warm
southern boundary pulsates on a spectrum of time and space scales, and about 10% of the
warm tropical Agulhas Current "leaks" into the South Atlantic. As previously explained
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most of this leakage is in the form of rings (eddies) which are shed from the Agulhas
Current as it retroflects. The main trajectory of these shed rings is west-north-west,
although departures from this have been recorded, and there exists a well documented case
of ring interacting with the Benguela upwelling system and drawing upwelled water off
the shelf in the form of a large curved upwelling filament. In addition to rings, there is a
small regular leakage of filaments of Agulhas water around the Cape of Good Hope just
west of the edge of the shelf and thermal front (which is associated with the upwelling).
On occasions there are substantial intrusions of Agulhas Current water into the southern
Benguela, of which the best documented case occurred in 1986 and coincided with that
year being among the warmest this century in the South-east Atlantic Ocean. Another
large intrusion occurred during the summer of 1997/8. Like its counterpart in the north,
these Agulhas intrusions appear to affect the living resources in the southern Benguela.
The location of the southern boundary is shown schematically in Fig.7, while the typical
extreme complexity of this boundary and retroflection of the Agulhas Current and
"leakage" is illustrated in Fig. 4.
Western boundary
The western (offshore) boundary of the Benguela is fairly open ended, but is generally
taken as approximately the 0° meridian. As such the Benguela sensu lato includes the
coastal upwelling area, the longshore fronts (see below) and the eastern portion of the
South Atlantic gyre. By definition then the Benguela Current comprises the total area of
equatorward flow in the upper part of the South-east Atlantic Ocean.
Longshore fronts
There exists over much of the area between Cape Frio (18°S) and Cape Point (34°S) a
well-developed longshore temperature front or fronts, which extends seasonally (in
summer) eastwards around the Cape of Good Hope. The oceanic thermal front
approximates to the seaward boundary of the general area influenced by coastal upwelling.
South of Lüderitz a single front is usually well defined, and although spatially and
temporally variable, coincides approximately with the run of the shelf break (edge of the
continental shelf). Further north the surface manifestation of the front is more diffuse and
multiple fronts are evident on occasions. The meandering nature of the front is evident in
satellite imagery (see Figs 4 and 8). Upwelling filaments which have a life span of days to
several weeks and which are generally orientated perpendicular to the coast cause the front
to become highly convoluted. Opinion as to whether these filaments are randomly
distributed or site specific are divided, although most recent evidence points to the latter
(which can be explained in terms of bathymetry and system dynamics).
3 CHEMISTRY AND RELATED PROCESSES
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Prior to 1925 very little was known about the chemistry of the South-east Atlantic Ocean
and adjacent areas, and it was not until data collected by the German Meteor Expedition of
1925 1927 were analysed and interpreted that a picture of the large-scale distribution of
elements of importance such as oxygen, phosphorous and silica began to emerge. In the
Benguela region, although the role of upwelling in the supply of nutrients (the dissolved
fertilisers in the sea) was appreciated as early as the 1930s, it was not until the publication
of the definitive work of Hart and Currie (1960) that the nutrient chemistry was placed in a
proper physical and biological perspective. Subsequent investigations by inter alia authors
such as De Dekker (1970), Calvert and Price (1971) and Andrews and Hutchings (1980)
resulted in a greatly improved understanding of the chemical-biological processes of
importance in the Benguela. The available information on the Benguela chemistry and
related processes was reviewed by Chapman and Shannon (1985) while recently Bailey
and Rogers (1997) have provided a useful overview of chemical oceanography within the
context of marine geoscience in southern Africa.
Before discussing the essential features of processes associated with the chemistry of the
Benguela system it is perhaps appropriate to explain some basic concepts so that readers
who are not oceanographers or chemists will more easily be able to follow the subsequent
discussions. Viewed very simply, macro-nutrients such as ammonia, nitrate, phosphate
and silicate are present in sea water at low but significant concentrations. Near the sea
surface these nutrients are consumed by microscopic plants (phytoplankton).
Photosynthesis takes place, and the phytoplankton multiplies or blooms, absorbing carbon
dioxide and releasing oxygen into the water. The phytoplankton is then either consumed
by small planktonic animals (zooplankton) and some fish species or otherwise sinks
slowly to the bottom. In this process bacteria play an important role, and as the
phytoplankton and also faeces and organic material from zooplankton and higher
consumers sinks, these decay. During the decay, oxygen dissolved in the deeper sea water
layers and sediments is consumed and nutrients are released back into the water column.
The overall process results in a lowering of nutrient concentrations in the surface layers
and an increase at depth, with the opposite situation applying to dissolved oxygen. Within
the context of a system such as the Benguela, it is the upwelling that is thus so important
in bringing the nutrient-rich deeper water to the surface where photosynthesis can occur,
and this explains why eastern boundary currents are so rich biologically. In the Benguela
there is an imbalance between phytoplankton and zooplankton and fish production, and
much of the decaying phytoplankton is deposited on the seabed, forming the organically
rich diatomaceous sediments which are characteristic of the larger part of the Benguela
shelf. In turn, processes which take place at the interface between the sediments and the
overlying water and in the water in the sediments (interstitial water) are chemically also
very important, in particular for the "regeneration" of nutrients.
Although what has been described is perhaps somewhat of an oversimplification of the
complex physical-chemical-biological interactions which occur, it does help to explain the
cycle.
3.1 Dissolved oxygen
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One of the major features of the Benguela region is the occurrence of large areas where
very low concentrations of dissolved oxygen are found. Thermocline Water (Central
Water) in the South-east Atlantic Ocean, which is the upwelling source water, commonly
contains between 4.8 and 5.2 ml/l dissolved oxygen and is about 80 85% saturated. In
contrast, the shelf waters in the Benguela system frequently contain much lower
concentrations, and on occasions at sites such as Walvis Bay the sea can become anoxic at
times, particularly at depth, while near the surface during phytoplankton blooms
photosynthesis can result in the surface layer becoming supersaturated with oxygen. The
occurrence of low-oxygen water is not only important in terms of the chemistry, but plays
a key role in controlling the distribution and abundance of several marine species not
only bottom-dwelling (benthos) like rock lobster, but also fish such as hake. To avoid
confusion, in the following paragraphs, we shall refer to water having an oxygen content
of less than 2 ml/l as "oxygen-deficient" and above 2 but less than 5 ml/l as "oxygen-
depleted".
The first comprehensive account of the large scale distribution of dissolved oxygen in the
South Atlantic was provided by Wattenberg (1938), and was based on measurements made
during the expedition of the Meteor a decade earlier. His work showed the existence of a
wedge-shaped tongue of oxygen-deficient water with its core lying at a depth of 300
400m, and extending from its base between the equator and 20°S at the African continent,
across the South Atlantic. Concentrations lower than 0.5ml/l were recorded in the
Benguela region near 15°S. The permanence of this major low oxygen feature in the South
Atlantic has been confirmed by all subsequent large-scale investigations.
Hart and Currie (1960) and others have demonstrated the existence of an oxygen-deficient
layer overlying the continental shelf north of Walvis Bay, and it is clear that oxygen-
depleted subsurface water is a characteristic feature of much of the northern and central
Benguela shelf. Subsequent studies have shown that low oxygen conditions can exist at
times on the shelf further south, for example near the Orange River, in St Helena Bay and
even at some sites on the Agulhas Bank. Hart and Currie (1960) suggested that the
oxygen-depleted shelf water might be transported southwards from the tropical South-east
Atlantic along the edge of the shelf in a deep compensation current, a view supported by
De Dekker (1970) and Andrews and Hutchings (1980) who put forward convincing
arguments in favour of this, and suggested that the oxygen-deficient water which occurs as
far south as the Cape Peninsula at times, originates from Namibia.
The most comprehensive study of dissolved oxygen off Angola and Namibia was that
undertaken by Bubnov (1972), and he suggested that the main oxygen minimum in the
South Atlantic forms in a broad area off Angola, and is reinforced by processes associated
with the Angola Dome. This is shown schematically in Fig. 9. Bubnov, however,
calculated that the level of primary production over the Namibian shelf was sufficient to
provide the concentrations of oxygen observed in the water column there in the absence of
any advection (horizontal movement) from the north, a view supported subsequently by a
number of authors. Interestingly, Poole and Tomczak (1999) show that the pseudo age of
this oxygen poor water off Angola is 50 years or greater, in contrast to the younger more
recently ventilated water south of 30°S which is less than 10 years "old".
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Thus, while southward advection of oxygen-deficient and oxygen-depleted water from the
Angola Basin via a poleward undercurrent may be an important mechanism controlling the
distribution of low oxygen water on and adjacent to the shelf, local processes over the
Namibian shelf are probably more important on average as determinants of oxygen
dynamics in the Benguela region per se. This view is reinforced by the properties and
distribution of the main oxygen minimum layer off Angola which are different to those of
the oxygen-depleted/deficient shelf waters off Namibia. Indeed two distinct maxima cores
have been observed on occasions, one over the shelf (locally produced) and a deeper one
(probably part of the main minimum layer) west of the shelf break. It does seem, however,
that the high primary production off Namibia is an important contributor to the main
oxygen minimum layer, the latter at times spilling onto the shelf and reinforcing the
depletion processes in Benguela shelf waters. There is also evidence that there is a slow
southward advection of oxygen-deficient water throughout the Benguela at least as far
south as the Cape Peninsula with lowest oxygen concentrations occurring during late
summer/autumn in the southern Benguela. The fact is that oxygen-deficient water
dynamics which plays a pivotal role in the ecosystem are not well understood. What is
known is that substantial interannual variability in the oxygen concentrations does occur
(discussed later) and that this is important for fisheries.
A conceptual model of areas where the low oxygen water forms and its movement is given
in Fig. 9. Readers are referred to Chapman and Shannon (1987) and Bailey and Rogers
(1997) for further information.
3.2 Nutrients
The general features of the distribution of nutrients in the Benguela resemble closely those
of other upwelling regions. The upwelling water is enriched in nutrients relative to the
surface layers and during active upwelling this water reaches the euphotic zone (the
biologically productive surface layer which sunlight penetrates) near the shore. Following
the establishment of the thermocline, phytoplankton production consumes nutrients in the
upper layers, leaving them much depleted, while nutrient re-enrichment occurs below the
thermocline as the phytoplankton decay. Chapman and Shannon (1985) pointed out the
difficulty in discussing the nutrient status of the whole Benguela because the chemistry is
very much site specific, and it is therefore not easy to generalise.
The shelf waters of the Benguela are, however, characterised by elevated concentrations of
nutrients in comparison with those in the surface mixed layer of the adjacent oceanic
waters, and also in comparison with concentrations in source waters. For example, South
Atlantic Thermocline Water contains about 0.8 1.5 µM (micro-moles) phosphate, but
shelf waters have phosphate concentrations typically between 1.5 and 2.5 µM, with values
as high as 8µM having been recorded off Namibia. Local regeneration processes are
important throughout the Benguela, but particularly off Namibia. In comparison with the
eastern boundary of the Pacific, source waters in the Benguela have lower levels of
inorganic nutrients, and consequently a lower potential for new production. (The term
"new production" is commonly used by marine chemists and biological oceanographers
and can be viewed simply as that based on outside sources of "fertilisers" such as nitrates,
unlike " regenerated production" which results from the locally produced waste material
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ammonia and urea based.). Typical concentrations of macronutrients in the Benguela
system are summarised in Table 1.
Table 1:
Nutrient concentrations (µM) in (a) offshore upwelling (b) shelf and (c)
oceanic surface waters in three areas of the Benguela, based on published
work.
Area
Phosphate Silicate
Nitrate
Cape Peninsula (a)
20 1.5 16
(b)
23
1.5
19
(c)
<1
0.5
5
St Helena Bay Orange River (a)
25
2
10-20
(b)
25
2.5-3
20-40
(c)
<1
0.5-1
8
Namibia (a)
15-25
1.5-2.5
5-20
(b)
10-30
2-3
20-50
(c)
<5
<2
<1
One generalisation which can be made is that the importance of nutrient regeneration in
the supply processes increases northwards in the Benguela system.
Whereas Thermocline (Central) Water of South Atlantic origin contains fairly similar
concentrations of nitrate and phosphate as South Indian Ocean Thermocline Water, the
silicate content of the latter is only about half of the former. This is significant for the
nutrient chemistry of the Agulhas Bank region, which can according to Lutjeharms et al.
(1996) be divided into distinct nutrient "provinces," the eastern off shore part of the Bank
being dominated by nutrient-poor Subtropical Surface Water and the western and inshore
areas influenced by nutrient-rich South Atlantic Thermocline Water. Although upwelling
occurs inshore in the lee of prominent capes, the Agulhas Bank system is strongly
stratified in summer, particularly so in the eastern part. As a consequence nutrient
concentrations tend to be higher in winter over the Bank as a whole in winter when the
shallow seasonal thermocline breaks down. Readers requiring further information are
referred to an excellent overview of the nutrient dynamics of the Agulhas Bank in Bailey
and Rogers (1997).
Published work suggests that silicate is the limiting nutrient at times in the northern
Benguela, while nitrate is on occasions limiting in the southern part of the system. This is
perhaps counter intuitive when it is considered that the Namibian shelf sediments are rich
in biogenic silica and Agulhas Current/Bank water (which leaks into the southern
Benguela) relatively poor in silica. Considerable advances have been made during the past
decade with respect to the assimilation of ammonia and nitrate by phytoplankton using
stable-isotope nitrogen fifteen (N 15) incubation techniques by authors such as Probyn et
al. (1990), Probyn (1992) and Waldron and Probyn (1992).
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A significant contribution to the understanding of nutrient dynamics and production was
made during the second phase of the Benguela Ecology Programme (1987-1992) with the
recognition of the importance of the microbial loop and the application of N 15 labelling
techniques to distinguish between newly incorporated nitrogen (NO3-N or N2) and
metabolically recycled nitrogen (NH4-N or dissolved organic-N, i.e. urea).
Using satellite-derived sea surface temperature imagery, Waldron and Probyn (1992)
estimated the potential new production in the Benguela system, and the first of these
authors subsequently went on to calculate new production during the 1980s using sea level
as a proxy for upwelling. Following on from work on carbon pathways in the southern
Benguela upwelling system (Waldron et al. 1998), Dr Waldron has kindly generated a
nitrate-nitrogen driven pathway for the Benguela as a whole for the purpose of this
overview. This is given in Fig. 10 and illustrates simply and dramatically the import and
export fluxes in shelf waters, in particular the nitrate-driven new production and the role of
the shelf sediments as a sink. This will be discussed further in the section dealing with the
foodweb and carbon budget.
3.3 Sulphur
Perhaps one of the most obvious features of the marine chemistry of the northern
Benguela is the odour of hydrogen sulphide gas which is associated with "sulphur
eruptions". These periodic eruptions are common in the general vicinity of Walvis Bay,
usually during late summer when upwelling is at a minimum i. e. under quiescent
conditions.
Sulphide formation results when anaerobic biological breakdown of organic substances
and bacterial reduction of sulphate which is present in sea water and in the interstitial
water in the marine sediments occur. As biological reduction of sulphate is an anoxic
process, sulphide formation can occur where there is above average oxygen consumption
or poor circulation - circumstances which may be associated with the decay following a
major bloom of phytoplankton in an embayment or even along an open coast under
quiescent conditions. These suboxic or anoxic conditions are common in the northern
Benguela shelf waters and underlying organically rich sediments, and this provides
suitable environmental conditions for the formation of sulphides by sulphate reducing and
anaerobic bacteria.
As hydrogen sulphide which may be formed in the process can be extremely toxic, even at
very low concentrations, mass mortalities of marine organisms are often associated with
the "sulphur eruptions"' compounding the effect of the already depleted oxygen content of
the sea water. Records of fish kills in the Benguela resulting from sulphide production go
back at least as far as 1928, but the occurrence of sulphide was not positively identified
until later (Copenhagen 1934). Sulphurous fumes are often present in the atmosphere at
coastal sites in central Namibia and may penetrate 60km or more inland. Their corrosive
effect on iron and steel and tarnishing of paintwork, brass and silver is visibly evident in
Walvis Bay and Swakopmund. During the sulphide events, mud islands may appear and
disappear, the smell of rotten eggs pervades the air, and the sea takes on an appearance of
boiling hence the term "sulphur eruptions". The most recent widescale sulphur eruption
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occurred in the Walvis Bay/Swakopmund area during March/April 1998 and was
characterised by a strong odour of hydrogen-sulphide. The sea along the coast turned a
milky-turquoise colour for as far as the eye could see.
The main area within which the sulphur eruptions occur is the so-called "azoic zone", and
free sulphur can be present in sediments from this area. Even 100km further south,
concentrations of sulphide as high as 65mg/l may occur in interstitial water in sediments
(Bailey 1979). Hydrogen sulphide concentrations of about 1ml/l have been measured in
the northern Benguela. In the southern Benguela, eg. St Helena Bay, even though
sediments may smell of sulphide, there are very few published measurements of free
hydrogen sulphide. However, during the autumns of 1994 and 1998 a strong odour of
hydrogen sulphide persisted for about a week in the atmosphere around Cape Town, as a
consequence of decaying phytoplankton blooms in the St Helena Bay area, suggesting that
sulphide events may be more common in the southern Benguela than hitherto appreciated.
In spite of the occurrence of sulphide in Benguela sediments and shelf waters, surprising
little research has been conducted on the subject. Apart from the relevance of such studies
to investigation and prediction of mass mortalities of marine life, public awareness and
interest is high. Moreover, what is perhaps not well known, but may be extremely
important in terms of industrial development along parts of the west coast, relates to the
solubilization of heavy metals. For example mercury sulphide which is insoluble in normal
oxygenated (oxic) water and sediments and is generally regarded as environmentally
harmless, can be transformed to polysulphides of mercury in the presence of low
concentrations of sulphide, and goes into solution thereby becoming a serious
environmental hazard.
3.4 Other aspects of marine chemistry
In their comprehensive review of the chemical oceanography of the Benguela system,
Chapman and Shannon (1985) also discussed other aspects of the redox chemistry,
including that of iodine and biomine, in addition to nitrate/nitrite and sulphate/sulphide as
couples. (An important reference work on the subject is Price and Calvert 1977 which
complements an earlier publication by these authors viz. Calvert and Price 1971).
Chapman and Shannon also reviewed published work on the minor elements, which in
contrast to the oxygen and nutrient distributions and dynamics have received very little
attention in the Benguela. Minor elements include inter alia the alkali elements
(potassium, rubidium and lithium), barium, and heavy metals. Many of the pioneering
measurements of metals such as copper, iron and manganese, which are trace nutrients,
were made by Orren (1969, 1971). As part of a South African marine pollution study,
these and trace metals such as cadmium, nickel, lead and zinc were measured in water and
sediments along the coast during the 1970s and 1980s eg. Eagle et al. (1982). Their results
were summarised by Shannon and Chapman (1985) as was the work of authors such as
Chester and Stoner (1975) on the concentrations of metals in dust and surface water
particles collected in the Benguela region. Excluding urban environments, most of the
measurements on metals in sediments have been from the organically rich Namibian shelf
region, and it would appear from the available data that the concentrations of metals in
these sediments are higher than observed in many other marine sediments.
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Man-made chemicals such as chloro-fluoro-carbons ("CFCs") have been detected in the
deeper water masses present in the South-east Atlantic. CFCs such as CFM-11 and CFM-
12 are useful tracers of water mass age and movement, and in the southern African context
of the exchange of waters between the South-east Atlantic, North Atlantic and Indian
Oceans.What the results also show is that even the deep bottom waters in the Southern
Hemisphere have potential to be contaminated by activities of industrial Northern
Hemisphere countries and can no longer be considered as pristine.
In conclusion it must be noted that chemical oceanography has for the past two decades
been very much a "Cinderella discipline" in southern African countries, and in spite of the
importance of chemical processes in regulating the biology of the Benguela ecosystem,
this has apparently not been adequately recognised by the fisheries and environmental
agencies.
4 PLANKTON AND THE FOODWEB
The literal translation of the word "plankton" is "wanderer", and the term applies to a
spectrum small neutrally buoyant ("free floating") organisms in the sea which have little
or no power of locomotion, and which drift with the currents. These small microscopic
plants and animals provide the primary food sources for a host of marine species and
constitute the early building blocks in the marine food chain or, more correctly, the
foodweb. The microscopic unicellular plants which occur in surface layers of the ocean
are known collectively as phytoplankton, while their animal counterparts are referred to as
zooplankton. Although the most common components of zooplankton are only a few
millimeters in size, zooplankton includes much larger floating animals such as jellyfish.
Useful reviews of plankton in the Benguela system are those of Shannon and Pillar (1986)
now a bit dated and Hutchings and Field (1997). Perhaps the most readable
introduction to the zooplankton of the Benguela Current region is Gibbons (1999).
4.1 Phytoplankton and primary production
Like all plants, phytoplankton require sunlight in order to photosynthesise, and
accordingly most of the organic productivity associated with these floating algae takes
place near to the sea surface. Phytoplankton can for all practical purposes be divided into
two categories viz. diatoms, which have no power of self propulsion and which have an
outer skeleton of silica, and those which have small hairs or flagella which enable some
weak motion viz. flagellates. The latter are generally more fragile than diatoms and are
associated with less-turbulent and more stratified waters. Diatoms are characteristic of
turbulent, nutrient-rich upwelled water. In upwelling systems the biomass of diatoms is
generally much higher than the biomass of flagellates.
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The Benguela is generally regarded as a diatom-dominated system. This perception is to
some extent an artifact of past sampling, which has tended to miss the very small cells or
nanoplankton. (The productivity of nanoplankton is regulated by regenerated nitrogen
see Section 3.2 and historically nanoplankton have been undersampled in the Benguela).
Both the northern and southern Benguela share many similar species assemblages, with
Chaetoceros, Nitzschia, Thalassiosira, Rhizosolenia being endemic throughout the region.
There are, however, essential differences between the north and the south, some of which
are linked to the atmosphere/ocean dynamics (e.g. nutrient supply, turbulence and
stratification). The diatom Delphineis karstenii (Fragilaria karstenii) is restricted to the
north, while Skeletonema costatum is found predominantly in the southern Benguela,
evidently having been most abundant in the early-mid 1960s and mid 1980s (both warm
periods in the system). The large cell Coscinodicus spp. commonly occurs in areas of high
turbulence. Over the Agulhas bank, the species assemblages are more cosmoplitan than
along the west coast. Microflagellates are common in the central area of the northern
Benguela e.g. Gymnodinium and Peridinium spp.
Phytoplankton abundance both from net and bottle sampling and chlorophyll a
measurements highlights the dichotomy between the northern and southern parts of the
system, with low values around 27-28°S (the base of the Lüderitz upwelling cell), and
high values downstream of the cell, and also further south associated with downstream
areas of the other upwelling cells (Namaqua, Columbine, Cape Peninsula). Off Namibia
during periods of active upwelling, highest concentrations of phytoplankton occur offshore
(50km), and during quiescent periods in a narrow band close to the coast. A characteristic
difference between the northern and southern Benguela is that concentrations of
chlorophyll a are generally higher off Namibia than off South Africa, being more
uniformly distributed in the former with less well defined chlorophyll fronts at the oceanic
boundary.
The advent of ocean colour satellite imagery in the late 1970s provided new insights into
the distribution and large scale dynamics of phytoplankton blooms. The Coastal Zone
Colour Scanner (CZCS) on the Nimbus-7 satellite in fact resulted in a quantum leap in
knowledge and understanding of the global distribution of phytoplankton, and southern
African oceanographers played an important role in the early validation of CZCS data and
application of satellite-derived ocean colour imagery in the study of upwelling ecosystems
and fisheries. After about ten years (which is a very long time for a satellite sensor to
function) the CZCS eventually failed, and it wasn't until very recently that a new and
much more sophisticated generation of colour satellites were launched and became
operational. Of these, the Sea-viewing Wide-imaging Field-of-View Sensor (SeaWiFS)
launched in August 1997 is the best-known and most user-friendly. Fig. 11 is a snapshot of
the distribution of plant pigments in the Benguela between 16° and 32° S from SeaWiFS.
In the southern Benguela chlorophyll is determined by wind cycles and displays
significant seasonality. Maximum concentrations tend to occur 20-80km offshore.
(Blooms following periods of active upwelling can extend 100km or more offshore).
Chlorophyll a concentrations in recently upwelled water, maturing upwelled water and
aged upwelled water are about 1, 1-20 and 5-30 mg/m3 respectively. Over the Agulhas
Bank phytoplankton production is largely controlled by thermocline/nutricline dynamics
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and the area is characterised by a deep chlorophyll maximum layer, at a depth of about
40m.
The total primary production in the Benguela system is approximately the same as that in
the Peruvian system, but substantially greater than off California. Brown et al. (1991)
provided an authoritative review of phytoplankton primary production and biomass in the
Benguela. Average values are given in Table 2.
Table 2. Average values of phytoplankton biomass and production.
Primary production (C14 uptake)
Phytoplankton
Biomass
g C/m2/d tons
C/y
Tons C
Northern Benguela (15°S-28°S)
2.6x106 1.2
77x106
Southern Benguela (28°S-34°S)
0.7x106 2.0
76x106
South-west Coast (34°S-30°E)
0.5x106 1.9
79x106
Bacterial biomass and production estimates range from a conservative 2-7% and 3-5% of
that of phytoplankton to 8-27% and 26-44% respectively in the least conservative case.
Substantial advances have been made with respect to the dynamics of phytoplankton-
blooms and plankton-ecology in general in the southern Benguela by drogue studies
(following patches of freshly upwelled water as it ages) and anchor station experiments.
(The latter were also done in the northern Benguela.) During the past decade a good
understanding of community structure and variability has been gained in the southern
Benguela which has showed systematic trends in dominant patterns of diatoms,
dinoflagellates and microflagellates in relation to upwelling, pulsing, turbulence and
stratification. The importance of phytoplankton seed populations in determining the
composition and time required for bloom development has been established and insights
have been gained into maintenance and life-survival strategies. In this respect, diatoms
tend to form spores which sink rapidly, and this enables them to remain in the nearshore
and nutrient-rich environments closer to upwelling centres (Pitcher 1990). Studies on rate
dynamics have enabled the quantification of the phytoplankton loss process to be made.
The knowledge gained in the south, if applied in the north, should facilitate a quantum
jump in the understanding of the dynamics of the Benguela at least in respect of
plankton processes.
4.2 Red tides and harmful algal blooms.
Outbreaks of red tide occur both in the northern and southern Benguela. They tend to be
observed most frequently close inshore, where their visual and at times harmful effects are
most apparent. Red tides are most frequent during quiescent conditions which follow
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upwelling, or during periods of light onshore winds and downwelling which commonly
occur in the southern Benguela during times of Pacific El Niño events. The red tide
causing organisms in the Benguela are generally dinoflagellates and sometimes ciliates,
and contrary to popular belief, most of the red tide species are non-toxic (Horstman 1981).
That red tides occur regularly in the Benguela is not unexpected. Diatoms, which dominate
the phytoplankton in the Benguela, have high nutrient requirements and are adapted to
turbulent conditions. The diatom blooms which are associated with upwelling events
quickly strip the nutrients from the upwelled water, and as the water column stabilises and
stratifies, this provides a suitable environment for dinoflagellates, which being tolerant of
low nutrient conditions, and favouring stable high light conditions, can then outcompete
the diatoms and "bloom". The dynamics of red tide blooms in the Benguela have been
studied in some detail, in particular in the south, during the past two decades by Dr G.
Pitcher and his coworkers. In a recent article Pitcher and Boyd (1998) have described from
an examination of the distribution of dinoflagellates across the continental shelf and of
currents the physical mechanisms responsible for red tide outbreaks, and for the
maintenance of motile populations within the system.
The most common red tide organism in the southern Benguela is Noctiluca scintilans, a
non-toxic dinoflagellate. It also occurs off Namibia. This organism has been associated
with fish mortalities, however, not through any toxin, but by depleting the dissolved
oxygen in the water during major blooms, and also evidently by clogging the gills of fish.
Noctiluca blooms have a characteristic bright orange colour almost luminous (see Fig.
12). The most common red tide species off Namibia appears to be Heterocapsa triquentra,
and like species of Gymnodinium, Gongaulex and Scrippsiella, it has been linked to
mortalities in fish. Most reported mortalities of marine life in the Benguela which have
been associated with harmful algal blooms (HABs), in particular mortalities of sand
mussels and benthos have been due to a few species of Gongaulex and to Mesodinium
rubrum. The latter species is also known to occur off Angola. Red tide outbreaks off
Angola were first reported in the scientific literature of the 1940s. A major bloom of
Prorocentrum balticum occurred between Namibe and Luanda in August-September 1951,
and was associated with high fish mortality (Silva, 1953) see also a comprehensive
account of red water on the coast by Paredes (1962). Pitcher (1999) recently reviewed the
pertinent information on HABs in the Benguela system. His report is an excellent
overview of the subject and introduction to the published literature.
Whether or not the frequency of red tides and HABs in the Benguela is increasing, is not
clear. What is known is that there are interannual fluctuatations in occurrences, probably
associated with changes in weather patterns. Moreover, in the late 1980s, "green tides"
occurred in the area east of Cape Point, in particular in False Bay. These outbreaks caused
large mortalities of sedentary organisms such as abalone and also led to respiratory
problems in humans swimming in, or in close contact with, affected areas of sea water.
The species responsible was Gymnodinium nagasakiensis and is though to have been
imported via ballast water discharges. However, relatively little is known about the extent
of exotic species introduced into the system from such discharges.
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4.3 Zooplankton and secondary plankton
Zooplankton in the Benguela ecosystem is dominated by small crustaceans (tiny shrimp-
like animals), the most important groups being copepods and euphausiids. Of these
copepods are numerically the most abundant and diverse group. Species diversity is
highest near the warm water boundaries of the ecosystem i.e. in the vicinity of the
confluence between the Angola and Benguela Currents, west of the oceanic front and shelf
break, and in the extreme south over the Agulhas Bank and adjacent Agulhas retroflection
area. Over the shelf, within the main upwelling system copepod diversity is lower, and
biomass higher, being dominated by a mixture of small (Paracalanus, Ctenocalanus,
Oithona, Clausocalanus), medium (Centropages, Metridia) and large (Calanoides,
Rhincalanus) copepods. Among the most common species are Centropages brachiatus,
Calanoides carinatus and Metridia lucens. On the Agulhas Bank the zooplankton biomass
is dominated by a single species, the large copepod Calanus agulhensis which has a centre
of distribution in the central-eastern part of the Bank over the endemic ridge of cool
water. Copepods play an important role in the trophic functioning of the Benguela
ecosystem. They are the principal food of anchovies and as a consequence they are the
most studied zooplankton group in the southern Benguela at least.
There are more than 40 species of euphausiids in the Benguela ecosystem. Of these
Euphausia lucens is the dominant euphasiid in the southern Benguela and Nyctiphanes
capensis in the north. Except in the central Benguela i.e. near Lüderitz, these two species
generally do not occur together. The latter species also occurs, however, east of Cape
Agulhas. Overall abundance of euphasiids appears to decrease towards the boundaries of
the Benguela ecosystem. Studies on the life history of euphausiids in relation to the
physical environment have led to an improved understanding of the role of euphausiids in
the ecosystem and also to a better understanding of the dynamics of the various fronts and
associated upwelling and sinking processes. Studies of the vertical distribution and daily
movement of euphausiids in the Benguela have shown that the younger stages to occur
near the surface and migrate little, while older stages occur deeper and display significant
migration. Euphausiids are important prey items for anchovy and hakes, and conversely
E.lucens is capable of capturing and consuming small fish larvae.
Thaliaceans (salps and doliolids gelatinous zooplankton) are common throughout the
Benguela. They are often indicators of intrusions of warm water, particularly in the
southern Benguela. Analyses of gut content suggest that thaliaceans feed mainly on
phytoplankton in inshore waters and on zooplankton offshore. The impact of thaliaceans
on zooplankton and ichthyoplankton (fish eggs and larvae) has not been quantified, but it
could be significant at times. Likewise the abundance and impact of other gelatinous
zooplankton, which is periodically abundant in the Benguela, in particular off Namibia
("jelly invasions"), has not been quantified.
In the northern Benguela peak abundances of zooplankton appear to coincide with periods
of maximum phytoplankton abundance viz. November December and March May, the
former following the main upwelling season and the latter during moderate upwelling
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when summer stratification weakens. In both cases the spatial distribution of zooplankton
differs from that of phytoplankton in that zooplankton tend to be more abundant offshore
of the (coastal) phytoplankton maxima (beltlike distribution parallel with the coastline).
This is probably an oversimplification. However, as there is a general lack of proper
quantitative estimates of zooplankton abundance and production in the northern Benguela,
coupled with the fishery-centred sampling bias.
In contrast, in the southern Benguela there are relatively good estimates of zooplankton
distribution, abundance and production. Zooplankton standing stock estimates in the
upwelling area off the Cape Peninsula display distinct seasonality, associated with the
upwelling cycle, with a winter minimum and a summer maximum. Superimposed on the
seasonal cycle is substantial shorter period variability (determined by upwelling pulsing,
the dynamics of the phytoplankton blooms and the life histories of the various zooplankton
groups). The series of drogue studies in the 1980s which followed an upwelling pulse and
tracked the processes as the freshly upwelled water parcels aged, have contributed
substantially to the understanding of plankton dynamics. In the southern Benguela the best
estimates of zooplankton production suggests that it is of the order of 80gC/m2/y.
Hutchings et al. (1995) have reviewed inter alia zooplankton grazing in upwelling systems
and highlighted a number of generally applicable principles which follow: Although
copepods and euphausiids have rapid responses to increased food in terms of egg
production, their response in terms of growth of juvenile stages to adulthood are much
slower. Behavioural adaptations promote maintenance in the upwelling circulation.
Juvenile stages remain near the surface; older stages migrate more extensively and are
advected back into inshore water again, allowing grazers to prolong contact with
phytoplankton blooms. Wind reversals/calms which allow phytoplankton to return
shorewards or be entrained in eddies as they develop may increase the phasing effiencing
between phytoplankton and zooplankton. Because of their limited mobility power,
zooplankters need to adapt behavioural responses to maximise contact with food items and
also minimise predation mortality. The recirculation of zooplankton may be favoured by
undercurrents, eddy structures such as exist near upwelling centres and inshore counter
currents. Like upwelling systems in general, in the Benguela zooplankton biomass maxima
tend to exist downstream from upwelling centres and it is these areas which are preferred
habitats of developing juveniles of fish species such as anchovy and sardine. Examples of
these areas are St Helena Bay, Orange River bight, near Walvis Bay and off northern
Namibia.
During the past decade Cape Town-based planktologists have focussed much of their
attention on copepod and euphausiid ecology, reinforcing field studies with experiments
using animals reared in the laboratory. This has led to a greatly improved understanding of
feeding requirements, growth rates and how zooplankton adapt to environmental
variability in the southern Benguela. Combined field-laboratory experiments have shown
that anchovy are size-selective feeders ("biters") rather than filter feeders and derive most
of their energy requirements from large copepods and euphausiids. Conversely sardine
(pilchard) feed predominantly by filtering even filtering relatively large zooplankton
such as euphausiids. Only when the density of large food organisms is very low does
biting become more important for sardine than filtering (Van der Lingen 1994). Whereas
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the energy costs of filter feeding for anchovy are high (higher swimming speeds result in
high respiration), for sardine the opposite applies i.e. the costs for filter feeding remain
much lower than for anchovy even at high swimming speeds, while more energy has to be
expended to orientate on prey in a biting mode (Van der Lingen 1995). This food
partitioning is illustrated diagrammatically in Fig. 13. The consequence of the different
feeding behaviour between anchovy and sardine is that sardine do better when small food
particles dominate as in stratified waters, whereas anchovy should do better when the sea
is dominated by larger particles, such as during turbulent upwelling conditions and might
explain why sardine and anchovy appear to undergo alternative phases of dominance in
upwelling regions over periods of 30-60 years (Hutchings and Field 1997). It might also
explain some of the observed differences between the southern (rapidly pulsed) and
northern (more uniform) parts of the Benguela ecosystem.
The past decade has also witnessed close collaboration between biological
oceanographers, physical oceanographers and fishery scientists fostered through joint
participation in hydroacoustic fish survey cruises, and this enabled the application of
oceanographic knowledge about mechanisms of upwelling and plankton dynamics to be
applied directly to solving fishery problems. Apart from obvious increased relevance of
research, it also resulted in a greatly improved fundamental understanding of biological
oceanographic processes and the role of these as a determinant of fish recruitment. Suites
of papers which have appeared in the South African Journal of Marine Science Volumes 5,
12 and 19 and other mainstream international journals document these developments,
while progress in various aspects of biological oceanography in the Benguela ecosystem
have been very adequately reviewed in a recent article by Hutchings and Field (1997).
Perhaps the most significant finding during recent years is that of Verhehe et al (1998)
who observed that crustacean zooplankton abundance, expressed in terms of number of
animals, increased by two orders of magnitude in the southern Benguela between 1951
and 1996,suggesting that a major change in the ecosystem has occurred. (This is discussed
in Section 5.)
Readers interested in the zooplankton of the Benguela ecosystem within the context of the
physics and chemistry and general biology of the South Atlantic Ocean are referred to a
recent review article by Boltovskoy et al (1999).
4.4 Foodweb and carbon budget
As Hutchings and Field (1997) have pointed out, grazing by copepods and euphausiids
and the sedimentation of organic material within the Benguela cannot account for the
decline in phytoplankton blooms after upwelled water has stabilised, so considerable
recycling of organic material must take place in the water column in the southern part of
the ecosystem. This has been confirmed by the application of stable isotope techniques
(N15 uptake methodology) by Probyn (1992), Waldron et al (1998) and others that the f-
ratio (a relative index of new production) in the Benguela is relatively low (0.2 0.3) -
only about one half or one third of the value in the Humboldt and California Current
systems (Refer also back to Fig. 10). Thus, despite the high rate of new nitrogen input to
the shelf waters via upwelling, much of the shelf water is dominated by the microbial
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foodweb fuelled by recycled nutrients (Hutchings et al 1995). Following the argument
further, as it is new production which determines the productivity at higher tropic levels
(fish), and as the food chain in the Benguela has been found to be much more complex
(and less efficient) than the classical 20% applicable in a simple short-food chain
(phytoplankton zooplankton fish), this to some extent explains why the Benguela
yields considerably less fish than 100 million tons which simplistic estimates might
indicate. Perhaps the most realistic model of the trophic functioning of the Benguela was
that developed by Moloney (1992), by incorporating the microbial foodweb. Her model is
illustrated diagrammatically in Fig. 14. The fundamental concepts embodied in this simple
sketch have major implications for understanding the functioning of upwelling systems
and their evident resilience! The understanding of the complexities of the foodweb and
underlying processes is an imperative for the management and sustainable utilisation of
the living marine resources of the Benguela ecosystem.
In a comprehensive examination of the mechanisms which drive the carbon flux in the
Benguela, Monteiro (1996) concluded that upwelling source water moves on to the shelf at
three principle sites which are determined by topography (the most important of these
being at 27°S near Lüderitz, the others being at 18°S at Cape Frio and at 32°S), and that it
is modified on the shelf, becoming enriched in nitrogen and carbon before eventually
outcropping at the main upwelling centres (of which there are six). Monterio (1996)
hypothesised that the three source sites act as "gates" or barriers to the southward
movement of water on the shelf. He developed a model which suggested that the water
which upwells at sites north of Lüderitz resulted in outgassing of carbon dioxide, while at
Lüderitz and further south, the "carbon pump" and biological activity result in that part of
the system being a carbon dioxide sink. Based on certain assumptions about dissolved
organic carbon, Monterio calculated that the Benguela system as a whole was a small
carbon dioxide sink of 0.34 1.5 million tons C/y. The better quantification of upwelling
systems such as the Benguela as sources or sinks of carbon dioxide has important
implications for the global carbon budget. The Achilles heel remains inadequate
knowledge about fluxes of dissolved organic carbon.
5 ENVIRONMENTAL
VARIABILITY
A complex array of processes affect the Benguela over a broad spectrum of space and time
scales, ranging from the molecular level and fractions of a second to those which span
several thousands of kilometers (basin-wide and global) and take place over several
months, years, decades or even longer.
There are a number of physical factors which are important determinants of the structure
and functioning of the ecosystem, and of these the wind and in particular the periodicity
in the longshore upwelling producing wind is of over-riding importance. The wind field
and wind frequency significantly influence coastal trapped shelf waters (these are internal
waves in the sea, referred to earlier), upwelling, formation of fronts, production of
filaments, surface and near-surface currents and the depth of the thermocline inter alia,
and a host of dependant chemical and biological processes. The large-scale wind field is
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also an important determinant of basin-wide circulation, and consequently changes in
winds even thousands of kilometers away can impact on the movement of water at the
boundaries of the Benguela and within the system.
Apart from winds, seasonal change in insolation (solar heating) is important, influencing
the temperature of the surface layer, its thickness and thermocline formation, while
variations in light intensity likewise are important in terms of photosynthesis and primary
production. What should be recognised is that over one third of the Benguela upwelling
area and all of Angola's coastal oceanic waters lie within the tropics, and consequently
receive high levels of thermal radiation and light. Tides and tidal currents are important in
the near-shore environments, especially in semi-enclosed bays, although in comparison
with coastal areas in those parts of the world which experience large tidal ranges, their
effects within the Benguela are relatively minor. (The tidal range in the Benguela is
typically 1-2m.) There are a number of similarities between the variability in the Benguela
and other upwelling systems, but there are also some important differences. What
distinguishes the system from other eastern boundary regions is the existence and
variations in the northern and southern boundaries viz. the Angola- Benguela front and the
Agulhas retroflection area. In addition, the variability in the southern Benguela caused by
the free passage of westerly winds and low pressure systems south of the sub-continent
make this area quite unique.
However, like in other upwelling systems which are pulsed, the biota in the Benguela
ecosystem are generally well adapted to the inherent variability in physical forcing on
seasonal and shorter time scales. The biota are, however, less well adapted to sustained
major events or changes which occur less frequently i.e. every several years or even over
decades. Accordingly, we provide only abridged comments on aspects of small-scale and
seasonal variability, and focus most of the discussion on the "catastrophic" occurences
which have system-wide impacts. We also highlight some long-term and decadal changes
which have been observed in the system.
5.1 Small-scale variability
Processes which occur on time scales of hours to several days and space scales of meters
to tens of kilometers are characteristic of upwelling events. These "event scale" processes
attracted considerable research attention in the 1970s and 1980s in the southern Benguela,
and much of this work has been reviewed by Shannon (1985), Chapman and Shannon
(1985) and Shannon and Pillar (1986). The application of remote sensing using aircraft
and satellites during wind events in combination with in situ measurements using ships,
provided knowledge about the initiation of upwelling, the growth and decay of upwelling
plumes off the Cape Peninsula and Cape Columbine following the onset, intensification
and subsequent reversal of the upwelling causing winds. Measurements in situ over hours
and days provided a good understanding of biochemical processes and plankton dynamics.
For example, by following patches of water and frequent sampling of these during
upwelling events, the supply and depletion of nutrients, effects of light and light
limitation, development of plankton "blooms", species successions, decay processes etc
were observed and quantified (e.g. Barlow 1982, Brown and Hutchings 1985). Although
most of this research was conducted in the southern Benguela, scientists from the former
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German Democratic Republic undertook off central Namibia in 1976 one of the most
intensive studies of the system over a period of a few weeks, using a combination of
repeated surveys along a line of stations and quasi-continuous sampling at a fixed station.
(e.g. Postel 1982). Their work showed vividly how the chemistry and biology of the water
column changes in response to changes in its physical structure. A somewhat similar
experiment was conducted in St Helena Bay a decade later and the findings were
published in a special issue of Progress in Oceanography (Volume 28).
There is so much information contained in the hundreds of scientific publications which
resulted from the era of event-type process studies in the southern Benguela, that it is just
not possible to condense it adequately and explain it simply. What is apparent, however, is
that there exists as superb body of information on the dynamics of upwelling and its
consequences in the southern Benguela. Volumes 5 and 12 of the South African Journal of
Marine Science published in 1987 and 1992 respectively contain many of the relevant
papers. The small and mesoscale processes in the northern Benguela and in Angolan
waters have, however, with few exceptions, received less attention. As the systems there
function differently from that in the south, simple extrapolation of results and application
of some of the concepts developed in the south to the Namibian and Angolan systems may
be inappropriate and misleading.
5.2 Seasonal changes and intra-annual variability
The large scale atmospheric weather systems over the south Atlantic display a seasonal
pattern of northward and southward migration, and the effect of this seasonal cycle
together with changes in insolation, manifests itself in the upper layer. The seasonal
changes in longshore upwelling wind stress have already been commented on in Section
2.2 (refer also to Fig. 2). Stratification also plays an important role in seasonal behaviour,
for example in the generation of internal tides and in the transport of water. Stratification
in the surface layer is intensified by the inflow of fresh warm water from the Congo River,
which drains much of central Africa. It seems probable that the Congo River exerts a
significant influence on the surface waters off Angola, as the presence of Congo River
water can be detected over distances of 1000km or more from its mouth (Dr M. E. L.
Buys, pers comm). Information about the seasonal and interannual nature and impact of
this water along the coast of Angola may be provided by an examination of the 30 year
long record from the monitoring station at Lobito and from other records.
Off Namibia and Angola, there is a distinct seasonal cycle in surface and upper layer
temperature, with a maximum in March and a minimum in August/September. The range
in seasonal average sea surface temperature is about 4° - 6°C . In the southern Benguela
the upwelling season coincides with the period of maximum insolation, and accordingly
the range in seasonal average temperature is only 1°-2°C. At the boundaries of the
upwelling system, the water column becomes strongly stratified during the austral
summer, particularly so over the eastern Agulhas Bank and off Angola, north of the
Angola- Benguela front (see Fig 6). The Angola-Benguela front migrates seasonally
between its northernmost location near 14°30'S in August and its southernmost position at
17°S in March, the latter being associated with a poleward push of saline Angolan Current
water. In the south, the boundary at the Agulhas retroflection likewise displays apparent
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seasonality, being furthest south in autumn (Dr C. A. Villacastin-Herrero, personal
communication). The Agulhas retroflection area is one of the global "hot spots" in terms
of variability of temperature and water movements. Apart from the impact of this
variability on the South-east Atlantic and the Benguela, it is also important for global
climate, as the area south of Africa acts as a veritable "choke point" or "valve" for the
movement of heat and salt between the Indo-Pacific and the Atlantic Oceans. (Most of this
heat is transported via the six or so rings which are shed each year from the Agulhas
Current, so changes in the frequency of ring formation can have major implications for
climate)
Although the seasonal changes evident in the upper layer correspond to the seasonal shifts
in the weather patterns and insolation, there are no obvious comparable changes in
currents. Indeed, the currents near the bottom over the shelf display much less seasonal
variability than that which occurs during "events" on 3 to 10 day time scales. There is,
however, some suggestion of seasonality in the southward extent of the oxygen depleted
shelf water, which reaches a maximum in summer/autumn.
The abundance of phytoplankton throughout the Benguela tends to be higher in summer
and autumn, and zones of highest concentration usually lie further offshore during the
season of upwelling. Taking the Benguela as a whole, the productive area appears to be
larger during summer and autumn than in winter and spring. Subsurface chlorophyll
maxima are common throughout the Benguela, particularly marked during summer and
autumn when water over the Agulhas Bank is strongly stratified. Storm mixing in areas
such as the Agulhas Bank and other shallow parts of the shelf can deepen and erode the
thermocline to such an extent that during some winters there is a complete destruction of
the thermocline, and the water column becomes well mixed from top to bottom. When this
happens higher concentrations of nutrients and consequently higher concentrations of
phytoplankton biomass and production can result.
Seasonal trends in zooplankton abundance tend to follow the phytoplankton cycle. Perhaps
the most comprehensive record which exists was that provided by Andrews and Hutchings
(1980). These authors monitored several parameters in the water column along a line of
stations off the Cape Peninsula monthly over three years, and showed that there was about
a twofold increase in zooplankton biomass during the upwelling season in the southern
Benguela compared with winter (typically 3g dry wt/m2 in January and 1.5g/m2 in
August). Further north in the Benguela, there appears to be less seasonality in zooplankton
abundance. What is also clear is that consumption of zooplankton by some fish species can
significantly reduce zooplankton abundance even result in "holes" in the distribution on
occasions, providing clear evidence that at times food in the form of zooplankton can be a
limiting factor for fish.
5.3 Interannual variability and episodic events
There are few reliable and long-term data series from the Benguela region. The longest of
these is for sea surface temperature (SST) and it dates from the early part of the 20th
century. The majority of the records of other physical, chemical and biological
oceanographic parameters are either shorter or are otherwise fragmented in space and in
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time. A consequence of this is that much of our present understanding of interannual
variability in the Benguela has been deduced from case studies of extreme or episodic
environmental events, in particular those which significantly impacted on fish abundance
and distribution. The most obvious of the extreme events which have occurred in the
Benguela are Benguela Niños (manifest by major incursions of warm tropical water from
Angola and from the west into the northern Benguela which occur on an average every ten
years), large scale hypoxia in subsurface and bottom water on the continental shelf,
anomalous large scale flooding of the southern Benguela by warm Agulhas Current water,
major intrusions of cold Sub-Antarctic Water in the south, and sustained anomalous
upwelling (or the absence thereof) caused by changes in regional winds. These major
environmental "perturbations" will be discussed presently.
A substantial amount of year-to-year environmental variability has been observed in the
Benguela ecosystem during the past two decades. The principal changes and fluctuations
which have been documented since 1980 can be summarised as follows:
Below average sea surface temperature in the shelf area of the northern and
southern Benguela during 1982 and 1983
A short-lived warm event in the extreme southern Benguela during early 1983,
associated with the large El Niño which occurred in the Pacific that year, and the
commencement then of an extended period of weaker than normal equatorward
winds near Cape Columbine (33°S). The period 1982-1983 saw an abrupt change
of 30° in the wind direction on the south coast which served to redress long-term
changes in the wind direction preceding the event
The 1984 Benguela Niño that followed the cool period in the northern Benguela
(but which had little impact on the southern region).This resulted in reduced
upwelling off Namibia, the intrusion of warm, saline tropical water from Angola
and offshore, deepening of the thermocline and changes in plankton and fish
A warm anomaly in the south in 1986, which coincided with the intrusion of
Aghulhas Current water into the South-east Atlantic, especially during the winter.
This resulted in favourable environmental conditions (short lived) for pelagic fish
An onset of cooling in 1987, i.e. a reversal of the warming trend with the influx of
Sub-Antarctic water into the southern Benguela in early 1987
A period of warming in the southern Benguela in late 1988 and early 1989,
evidently associated with changes in the Agulhas retroflection, and a short-lived
intrusion of warm water
Sustained cooling of shelf waters in the southern Benguela from autumn 1989, and
the termination of the negative equatorward wind anomaly (at 33°S) which
commenced in 1983. Period of two months of below average reversal of flow at a
current meter site at 33°S, completely uncharacteristic of the record, occurred
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during winter 1989. The abundance off the west coast of the copepod Calanus
agulhensis (endemic to the Agulhas Bank) decreased between 1988 and 1991
An extended period of below-average trade winds in the extreme south that
commenced in the latter part of 1990
An eighteen month long cool period commenced in the extreme northern Benguela
in mid-1991, with pronounced upwelling off northern Namibia and Angola
Intrusion of an Agulhas ring during November and December 1992 adjacent to the
coast near Cape Point
Anomalously strong south-easterly winds in the southern Benguela during the
summer of 1993/1994 which resulted in strong upwelling along the west and south
coasts, and coinciding with a widespread negative SST anomaly in the South
Atlantic
Development and poleward propagation of major hypoxia on the shelf over the full
extent of the Benguela region and the occurrence of "black tides" during 1994
Benguela Niño during 1995 in the northern and central Benguela, characterised by
poleward flow and widespread warming and altered fish distribution and
abundance
Return to more normal environmental conditions in the northern Benguela in 1996 and 1997
A large intrusion of Agulhas water into the southern Benguela during the summer
of 1997/1998, followed by a large bloom of red tide organisms in the St Helena
Bay area, localised hypoxia, and an odour of hydrogen sulphide along the coast as
far south as Cape Town
The term "Benguela Niño" was coined by Shannon et al. (1986) and refers to large scale
episodic warm events that occur along the coast of southern Angola and Namibia every
ten years on average, and which have a character not unlike the El Niño in the Pacific
Ocean. Every few years the tropical eastern Atlantic becomes anomalously warm as a
consequence of relaxation in the trade winds and the deepening of the thermocline and
reduced loss of heat from the ocean to the atmosphere. Occasionally, every ten years on
average, this warming is even more extreme, evidently as a consequence of a sudden
relaxation of the winds off Brazil, and when this happens the warm water anomaly in the
tropical Atlantic travels eastwards and southwards, trapped (guided) by the coast of
Africa. The result is a large southward displacement of the Angola-Benguela front, and a
flooding of the Namibian shelf by warm tropical water sometimes very saline (1984), at
other times low surface salinity (1995) depending on the orientation of the flow and the
amount of fresh water from the Congo River present. Benguela Niños are accompanied by
increased oxygenation of subsurface and bottom shelf waters either as a consequence of
reduced deep flow of water southwards from Angola, or (more likely) reduced primary
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production and decay on the Namibian shelf. Benguela Niños are less frequent than Pacific
El Niños. Just like in the Pacific they are superimposed on the seasonal cycle, but unlike
the Pacific the seasonal changes in the Atlantic much larger, and the Atlantic or Benguela
Niños, have a smaller signal. Benguela Niños occurred in 1934, 1949, 1963, 1984, 1995
and probably around 1910, in the mid-1920s and in 1972-74. The most recent event and its
biological impact has been well documented by Gammelsrd et al (1998). Benguela Niños
are not necessarily in phase with Pacific El Niños, but they do appear to be a regional
response to changes in the global atmosphere-ocean system.
Just as Benguela Niños are associated with extreme disturbance of the Angola Benguela
front, extreme disturbances in the retroflection (turning back) of the Agulhas Current at
the southern boundary of the Benguela can be manifest as a major incursion of Agulhas
water moving into the Benguela system around the Cape of Good Hope. These intrusions
may be in the form of shallow surface filaments of warm water (the more usual case), but
on occasions warm rings shed from the Agulhas Current can take a more northerly path
than usual and impact on subsurface and deeper currents along the edge of the continental
shelf as was the case in 1989. A well documented Agulhas intrusion occurred in 1986
(Shannon et al 1990). Previous large-scale intrusions may have occurred in 1957 and
1964. The most recent event took place during the post austal summer (1997-1998).
Whereas Agulhas intrusions result in the input of anomalously warm water into the
Benguela, incursions of cold Sub-Antarctic water do occur, and occasionally the effect of
these can be felt as far north as 33°S (north of Cape Town), as was the case early in 1987.
It seems that these rather unusual events are associated with the shedding of rings at the
Agulhas retroflection, and they have an appearance of a compensatory northward flow
from the Sub-tropical Convergence following the formation of a ring. Their biological
consequences in the Benguela are unknown.
Changes in the strength and direction of longshore winds can, if prolonged over several
months or longer, result in periods of anomalously low temperatures along the coast
(increased upwelling) or warmer conditions associated with more quiescent conditions and
downwelling. For example, the abnormally cool shelf waters present in the northern
Benguela in the early 1980s were associated with a prolonged period of stronger than
normal longshore winds. Cool conditions were again characteristic of the early 1990s off
Namibia, while in the southern Benguela in 1993/94 the enhanced upwelling was a
consequence of stronger south-easterly winds that summer. Perhaps the most dramatic
changes occur on the south coast where surface temperatures lower than 10°C can result
on occasions following periods of anomalous easterly (longshore) winds. These conditions
tend to occur during times of Pacific La Niñas, while during El Niños, westerly winds tend
to dominate the Agulhas Bank system and result in downwelling at the coast.
During some years, the most recent being 1993-1994, the oxygen depletion of shelf waters
in the Benguela is unusually severe, and this results in widespread anoxia and hypoxia in
the system. Although most pronounced in the northern Benguela, episodic depletion of
oxygen does occur in the southern Benguela (e.g. in autumn of 1994). These large scale
hypoxic and anoxic conditions appear to coincide with quiescent conditions which follow
periods of sustained and enhanced upwelling as a consequence of increased primary
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production and subsequent decay of phytoplankton blooms (e.g. red tides). It also appears
likely that changes in the composition and flow of subsurface waters, in particular the
concentrations of dissolved oxygen in/and the southward moving undercurrent along the
west coast may be contributing factors, and this suggests that processes taking place off
Angola may exert an important influence on the Benguela ecosystem via advection
(currents). Irrespective of the causative mechanisms, large scale hypoxia and anoxia result
in massive mortalities of marine organisms and changes in distribution and abundance of
fish such as hakes (e.g. Hamakuaya et al 1998). The spectacular impact of such events on
non-swimming benthic animals e.g. rock lobsters, is shown in Fig. 16. In the northern
Benguela the widespread occurrence of oxygen depleted/deficient water does not coincide
with Benguela Niño events, but appear to precede these.
5.4 Decadal changes and regime shifts
There is a growing body of evidence which suggests that marine ecosystems undergo
decadal-scale fluctuations driven by variability in climate. This is most apparent at the
higher trophic levels (fish). For example in the Humboldt Current system decadal period
switches in dominance between sardine and anchovetta have occurred this century, and it
is also apparent from the sediment record (from analysis of fish scale deposits) that species
alternations have occurred during past centuries i.e. prior to the advent of fishing and other
anthropogenic impacts. Moreover it has been demonstrated that populations of sardine in
different parts of the Pacific (off Chile/Peru, California/Mexico and Japan) have
undergone synchronous fluctuations this century. In the Benguela ecosystem there have
been corresponding fluctuations in sardine abundance, although these appear to be out of
phase with those in the Pacific. Also, there is evidence in the southern Benguela, at least,
of species alternations-regime shifts- between anchovy and sardine, and in the northern
Benguela the sediment record suggests that both species undergo decadal-scale
fluctuations, at times alternating species dominating, at others the two species fluctuating
synchronously (e.g. Shackleton 1986). What is also apparent from the sediment record is
that there can be long periods (several decades) where both species are absent or only
present at a low biomass.
As previously indicated, there are few long-term data series of environmental parameters
for the Benguela region. The available indices do, nevertheless, show that changes and
fluctuations on decadal or longer time scales have occurred in the Benguela this century,
and superimposed on this variability a progressive warming of surface waters of about
0.7°C from 1920 is apparent throughout the Benguela and South-east Atlantic (This value
has been corrected for changes in measuring instruments). The analysis of Taunton-Clark
and Shannon (1988) showed that the 1920s and 1930s were cool years in the region and
that a change to warmer conditions took place during the 1940s, followed by a gradual
strengthening of the south-easterly trade winds over the next few decades. A system-wide
change occurred in the late 1960s, to be followed by an extended warm period. The
warming trend accelerated during the 1980s and this decade was the warmest this century
in the South-east Atlantic. Longshore wind stress in the Benguela increased sharply after
1974 and the shelf waters along the west coast of South Africa and Namibia were
abnormally cold in the early 1980s. In the southern Benguela (at least), wind record
displays a sharp change in 1982/1983, with significantly lighter winds blowing for the
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remainder of the decade (Shannon et al 1992). It is perhaps significant that there is
substantial decadal-scale variability evident in the post 1960 winds off Brazil (Carton and
Huang 1994). The Gulf of Guinea temperature records also suggest an apparent periodicity
between large sustained warm events of about 10 years.
While the physical mechanisms linking decadal variability observed in the South-east
Atlantic with that of the Indo-Pacific and North Atlantic is not understood, it is likely that
the Benguela is influenced by external changes, and must be viewed within the context of
the global ocean-atmosphere system. Generally, warming/cooling in the tropical Atlantic
appears to be out of phase with that in the Pacific. What is also quite conceivable is that
changes in the formation of Deep Water in the North Atlantic such as occurred in the
late 1960s during the "great salinity anomaly" will alter the northward movement of heat
through the Atlantic and the flux of water and heat south of Africa. (Note that the South
Atlantic is the only ocean where the net movement of heat is towards the equator, and
much of this comes from the Indo-Pacific.)
While decadal-scale changes are evident from some of the physical parameters and in fish
populations, these are not so apparent in the chemistry and plankton because of the
fragmented nature of the available records. The available information does however point
to the likelihood that comparable changes in the plankton has taken place, and by
extrapolation from the biology and physics, that changes in nutrient supply have also
occurred. Brown and Cochrane (1991) analysed chlorophyll a (a proxy for phytoplankton
biomass) data available for the southern Benguela between 1971 and 1989. Although there
appears to be a decreasing trend during the two decades from about 3.5 mg/m3 to 2.0
mg/m3, it is not statistically significant because the data are highly patchy. In what is
perhaps the most important paper on zooplankton in the Benguela during recent years,
Verheye et al. (1998) found that the abundance of animals in all main toxonomic groups
in the St Helena Bay area increased by at least ten fold between 1951 and 1996 (These
measurements applied to the main pelagic fish recruitment season viz March-June). Total
zooplankton abundance expressed in numbers of animals increased by more than one
hundred fold. The increase was accompanied by a significant shift in the community
structure of near shore zooplankton, with a trend towards smaller size organisms. Whether
the observed change is a consequence of reduced predation pressure by anchovy and
sardine ("top down control") or climatologically induced viz upwelling, primary
production and entrainment ("bottom up control"), is not clear at this stage. Other changes
in zooplankton include the decrease in abundance on the west coast of the copepod
Calanus agulhensis between 1988 and 1991 (previously mentioned) and the relative
scarsity of the euphausiid Nyctiphanes capensis now in comparison with the 1950s (E.
lucens is currently dominant).
5.5 Recent developments
In March/April 1998 environmental variability in the South-east Atlantic was the focus of
an important International Symposium and Workshop, held in Swakopmund, Namibia.
Hosted by the Namibian Ministry of Fisheries and Marine Resources and sponsored by
The World Bank, BENEFIT, the German Agency for Technical Cooperation (GTZ), the
Royal Norwegian Consulate General in Windhoek (Office for Development Cooperation)
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and the Scientific Committee for Oceanic Research (SCOR) of the International Council
for Science (ICSU) provided a showcase of current knowledge and ideas about
environmental variability in the Benguela, possible linkages/teleconnections with
variability elsewhere in the Atlantic Ocean and with the global system, the time and space
scales of the variability and ecosystem implications. Ninety leading scientists participated
in the Symposium/Workshop. Of these 30 were from overseas and another 5 were
international experts seconded to-or resident in- the SADC region, making this meeting
among the most international of any oceanographic conference held in southern Africa.
Comprehensive proceedings are available (Shannon and O'Toole 1998).
6 ISSUES, PROBLEMS, THREATS AND GAPS IN KNOWLEDGE
The different, but complementary, processes associated with the development of
BENEFIT and the BCLME, as well as national strategic planning initiatives have
generated a wealth of information about the main environmental issues, problems and
threats in the Benguela region and gaps in knowledge and understanding. Various reports
e. g. Anon (1997), Hempel and Haslund (1997), Shannon and O'Toole (1998) and Croll
(1998) document these fairly comprehensively. Accordingly, the following sub-sections
draw on the available literature, although obviously we have had to synthesise and provide
a degree of re-interpretation of the various views and perceptions.
6.1 Fundamental issues
As pointed out earlier in this Overview, the Benguela differs from other upwelling
ecosystems in several respects, e. g. it is bounded on northern and southern ends by warm-
water regimes and strong fronts are associated with these boundaries; in the southern
Benguela upwelling is strongly pulsed on a time scale of 3 10 days due to the free
passage of low pressure systems moving past the African continent; the Agulhas
retroflection results in a high degree of complexity and variability which does not have an
equivalent in any other upwelling area, and results in a net movement of heat in the South-
east Atlantic towards the equator and conduit linking the Benguela with the Indo-Pacific;
the continental shelf is very variable in depth and width; a key fish spawning area exists
upstream of two important upwelling centres and planktonic fish and larvae utilise a
strong jet current to move to the recruitment area; the northern, central and southern parts
of the Benguela function very differently, with the peak upwelling seasons in the north and
south being distinctly out of phase, either in synchrony with , or opposing, the annual
solar-heating cycle. The complex and unique character of the Benguela thus necessitates
special attention. Ideas and principals developed elsewhere will not necessarily be simply
transferable and applicable to the Benguela.
To date little attention has been given to transboundary environmental issues and the
management of these. This is largely due to the nature and location of the external and
internal system boundaries. The northern boundary of the main upwelling system viz the
Angola Benguela front lies close to the country boundary between Angola and Namibia,
while the major "internal boundary" feature viz the Lüderitz upwelling cell which
effectively divides the Benguela into northern and southern parts is not far from the
Namibia-South Africa border. The colonial past, coupled with the distinct distributions of
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the principal harvested living marine resources has resulted in the countries in the region
focussing activities within their own EEZs. Moreover the civil war in Angola and political
problems in the region during the 1970s and 1980s resulted in scant attention being given
to cross-system boundary environmental issues. A question which needs to be addressed
within the context of the BCLME is definition of the northern boundary of the Benguela
Current large marine ecosystem per se. Perhaps the term Greater Benguela Current
System might be appropriate as this would clearly include the Angolan region and the
Agulhas retroflection?
Management of Benguela living and non-living resources has in the past not been
integrated adequately either within countries or within the region. There has also been a
general lack of an ecosystem approach to the management of living marine resources,
although attempts have been made to take environmental considerations into account, for
example, in setting catch levels in the different countries. The real challenge for the
BCLME initiative is the development of viable integrative environmental mechanisms for
the region as a whole i.e. at the ecosystem level.
6.2 Environmental variability
Although the Benguela environment displays a high degree of variability across a wide
range of time and space scales, there is a growing realisation and consensus that it is the
major sustained events and changes which seem to impact on the ecosystem as a whole.
From a management point of view, there is a need to predict these large environmental
events and changes, and the impacts of these on the system. There is evidence that the
Benguela responds to basin-scale processes, in particular changes in the physical
environment in the tropical Atlantic (e.g. changes in windstress off Brazil) and in the
North Atlantic (e.g. North Atlantic Oscillation), changes in the Southern Ocean (e.g.
Antarctic Circumpolar "Wave") and to those in the Indian Ocean (variations in winds, the
flow and leakage of the Agulhas Current). These changes are in turn are linked to global
ocean-atmosphere processes. In other words, the Benguela must be viewed within the
context of the global environment, not in regional isolation. However, the problem is that
the teleconnections and linkage processes are not properly understood. Nevertheless,
documented changes in the state of the ecosystem and regime shifts are congruent with
decadal scale changes which have taken place in other ecosystems, but again it is difficult
to distinguish between a natural environmentally driven cause (bottom up) and that caused
by humans (top down). At the First Regional BCLME Workshop, the changing
environment was a key issue raised within all three working groups. What is very clear,
however, is that predicting environmental variability and change and the impacts is likely
to be extremely difficult - yet so important. It will necessitate comprehensive monitoring,
process studies and modelling at the very least.
While it is apparent that major environmental events such as system-wide hypoxia/anoxia
and Benguela Niños as well as changes in primary and secondary production, occurrences
of harmful algal blooms (red tides), changes in currents etc are important determinants or
indicators of ecosystem variability and change, the present level of environmental
monitoring within the Benguela region is totally inadequate to document these let alone
to use the information for any predicting or forecasting. The issue of environmental
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monitoring in the Benguela was addressed in some detail at an International Workshop
held in Swakopmund in April 1998, and a monitoring framework was developed (mainly
for Namibia). Implementation of a cost-effective regional monitoring strategy and system
along these lines is seen as an important component of the BCLME programme. However,
environmental monitoring will be expensive and is not readily automated. Although
obviously satellite remote sensing will comprise an essential element of the environmental
monitoring, it will require appropriate in situ measurements ("ground truthing" or
validating) to be useful.
Some of the more obvious features/issues re environmental variability in the Benguela e.g.
harmful algal blooms and the role of sulphur in the ecosystem (cf sulphur "eruptions") will
be addressed at specialist international workshops which are scheduled to take place in
Namibia within the next six months. The possible expansion of a monitoring buoy
network from the tropical Atlantic to the Benguela (PIRATA array) is being examined.
The introduction into the ecosystem of exotic species of marine organisms accidentally e.
g. via ballast water discharges from ships entering ports, or deliberately e.g. unauthorised
mariculture ventures, is a potential threat, but remains unquantified. Perhaps the biggest
threat to the Benguela is from the cumulative effect of small changes, some of which may
be imperceptible, as a consequence of human activity in the region (fishing, mining etc)
and as a consequence of global climate change.
6.3 The Benguela and global environmental (climate) change.
There are two issues here, viz the role of the greater Benguela ecosystem in global climate
change processes, and the impact of climate change on the Benguela. With respect to the
first issue, there is some uncertainty as to whether the Benguela is a net source or sink of
atmospheric carbon dioxide (see Section 4) with the "physical pump" supplying CO2
through outgassing from upwelling opposing the "biological pump" which will remove
CO2 from the atmosphere through primary production and the marine food web. Work of
Monteiro (1996) indicates that the southern Benguela may be a net sink and the northern
Benguela a net source, with the Benguela as a whole being a small sink. However, if the
Angola region and Angola Dome were to be included, the picture may alter radically.
Similarly changes in primary production and the marine food web could further alter the
balance in future. Thus knowledge of what happens in the Benguela and other upwelling
systems is important for global models predicting future climate change. A problem is that
very few studies have been made in the Benguela on the flux of carbon, and this is
exacerbated by the dearth of marine chemists in southern Africa and the low priority given
by regional funding agencies to marine chemistry.
The importance of ocean processes in climate studies and prediction is highlighted by the
fact that the top 1 metre of the sea contains as much heat as the entire 50km overlying
column of atmosphere! More-over, the South Atlantic is the only ocean in which there is a
net movement of heat from the south to the equator. This is in part due to the "leakage" of
warm Agulhas Current water into the South Atlantic via the Agulhas retroflection "choke
point" or "valve". This area is part of a global ocean heat "conveyer belt" linking the
Pacific, Indian and Atlantic Oceans which has a return cold conveyer arm deeper down.
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This is illustrated schematically in Fig 17. When global climate warms the conveyer
speeds up, when it cools it slows down. Thus the marine environmental processes which
take place in the southern part of the greater Benguela system viz in the Agulhas
retroflection may area have an enormous impact on world climate. This is recognised
internationally, and highlights the global importance of the Benguela environment the
conduit for the heat, a veritable global climate valve.
Global climate has warmed by about 0.8°C this century, and the balance of evidence
suggests a discernable human influence on global climate. If it is accepted that significant
change will occur in global climate in the next century, this is likely to impact on the
Benguela not so much through small increases in ocean temperature and sea level
(expected to increase by about 50cm by the end of the 21st century) but through changes in
wind over the South Atlantic and Indian Oceans. Coastal winds are likely to strengthen
and if this happens, upwelling will intensify and the present upwelling area may expand.
This in turn would have consequences for primary production and the food web and also
for global climate. In addition there may well be impacts from increased levels of
ultraviolet radiation resulting from the destruction of stratospheric ozone by CFCs. (In this
respect the "ozone hole" is still expanding). There remains so much uncertainty about the
likely changes and interactions, that any scenarios developed at this stage would be purely
speculative. Nevertheless it would be reasonable to anticipate that ecosystem changes and
regime shifts will occur during the 21st century and that these changes are likely to impact
on the economies of Angola, Namibia and South Africa. This again highlights the need for
appropriate environmental monitoring, studies of cause and effect and modelling with the
view to improving predictability. However, the impact of changes in the Benguela marine
environment may be dwarfed by the likely impact of climate change on rainfall in
southern Africa and of this on the economy of SADC countries.
6.4 Gaps in knowledge and understanding
Some of the more obvious shortcomings or gaps are listed below in point form. (These are
not in any particular order)
Teleconnections between the Benguela and the tropical Atlantic, North Atlantic,
Southern Ocean and Indo-Pacific and the linkage mechanisms (cf global weather
patterns)
Predictability of environmental change and ecosystem response
Dynamics of formation, advection and impact of oxygen deficient/depleted water
in the greater Benguela system (hypoxia/anoxia phenomena)
Dynamics of the Angola Current, its variability, and associated processes
Role of the Walvis Ridge physical, chemical and biological
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Various atmosphere-water-sediment chemical processes
Angola Benguela front dynamics and stability and biological impact thereof
The Benguela undercurrent and spatial continuity
Changes in system wide plankton abundance and species composition, during the
past 50 years. (Samples exist, but require analysis and interpretation)
The Benguela sulphur cycle/system and its biological consequences
Plankton production in Angola's EEZ and in the Angola Dome, and associated
biochemical processes
Harmful algal blooms (red tides) distribution, frequency, species,impacts
Extent and impact of exotic species of marine flora and fauna introduced from
ballast water discharges (control measures?)
Seasonal and interannual variability of the Agulhas Current and Agulhas
retroflection
Extent of marine pollution in the Benguela and its impact
Impact of climate change on the Benguela ecosystem
Quantification of the greater Benguela as a net source or sink of carbon dioxide
Environmental (ecosystem) impact of offshore mining activities and oil/gas
exploration/extraction
Transboundary environmental policy/management
Human-environment-resource interactions : quantification of natural
environmental variability vs human impact on the ecosystem
6.5 Infrastructure and human capacity
Comprehensive information about human capacity and infrastructure available in Angola,
Namibia and South Africa and shortcomings is provided in Appendix I.
The principal constraints and problems are briefly as follows:
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There is a steep gradient from south to north in terms of both expertise and
infrastructure. In the case of Angola, while laboratory and office accommodation is
good, there is a general lack of laboratory equipment and instruments and the
necessary support infrastructure. There are few scientists dedicated to
environmental studies in Angola, with a lack of chemical and biological
oceanographers. Namibia has excellent facilities but few posts are allocated to
environmental research and monitoring.
Except in South Africa, there is a general lack of trained and experienced
technicians to operate and support (service/maintain) high technology equipment
and to provide the necessary technical support to research staff. This shortcoming
has serious implications for environmental monitoring programmes, and results in
inefficient use of oceanographers with interpretive skills
There are relatively few scientists in the region with broad-based interpretive skills
i.e. who can integrate and synthesise across disciplines. There is also a shortage of
modellers, although this is being addressed by South Africa
There are very few marine chemists and chemical technicians in the region
including in South Africa. Marine chemistry is de facto the "Cinderella" activity in
the Benguela
While there is a need throughout the region to develop oceanographic expertise, in
particular in Angola but to a lesser extent also in Namibia and South Africa, there
is a shortage of tenured posts available for new graduates from universities and
technikons i.e. there are needs, but few available jobs
Angola does not have a viable research ship, and relies on assistance from Norway.
The situation in Namibia and South Africa is more satisfactory, although funding
and manpower constraints in the last mentioned country are making it difficult to
operate research ships such as F.R.S Africana (which is now 17 years old)
6.6 Funding
Funding for marine science and technology throughout the region is limited, and is
decreasing every year in real terms, because of other more pressing national priorities. In
Angola salaries of qualified scientists at IIP are very poor and staff are obliged to seek
alternative means to supplement incomes. Environmental research and monitoring is seen
in all countries as a lower priority than e.g. resource based work as it has a longer "pay
back" period (cf pure research vs applied research). As a consequence funding for marine
environmental research and monitoring in the Benguela is inadequate even in South
Africa. Unless the funding problem can be addressed adequately, and also flexibility to
utilise funds improved, there will be little prospect of a viable environmental component
within the BCLME
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7 ACKNOWLEDGEMENTS
The authors are most appreciative of the help and encouragement provided by the various
experts consulted during the preparation of this overview. In particular we wish to
acknowledge with sincere thanks support from staff of the governmental lead agencies in
the three countries participating in the Benguela Current Large Marine Ecosystem
Programme viz. Ministry of Fisheries and Marine Resources (Namibia), Instituto de
Investigaçao Pesqueira (Angola) and Sea Fisheries Research Institute of the Department of
Environmental Affairs and Tourism (South Africa).
This Overview was funded by The World Bank via a Block B grant from The Global
Environmental Facility (GEF) with The United Nations Development Programme (UNDP)
as implementing agency. Assistance provided by UNDP staff, both in New York and
Windhoek, is acknowledged with appreciation. The work was guided by the BCLME
Management Committee, the Members of which provided useful comments and helpful
advice.
The Benguela-Environment-Fisheries-Interaction-Training Programme (BENEFIT), a
regional initiative of Angola, Namibia and South Africa which was launched in 1997 was
a catalyst for the development of the BCLME Programme. This Overview draws on
information and ideas generated by the embryonic BENEFIT, and from the regional and
international oceanographic experts who have participated in the initiation of BENEFIT.
Valuable information on the Angolan component of the Benguela environment was
provided by Messrs. V. L. L. Filipe and F. Pereira, of the IIP in Luanda, while a recent
report prepared by Drs G. Hempel and O. H. Haslund on the status of marine science in
Angola was an important source of information about Angolan institutional capacity. Dr
H. Marques, Advisor at IIP, Luanda, provided many useful comments and suggestions on
the draft text which has been revised accordingly.
Satellite images of the Benguela were kindly provided courtesy of Ms S. Weeks
(OceanSpace CC) and her assistance in this respect is gratefully acknowledged. The
majority of the diagrams were generated by Mr A. P. van Dalsen (SFRI) whose
considerable cartographic skills are apparent in the illustrations.
8 REFERENCES
During the past decade several thousand scientific publications on the Benguela ecosystem
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these follow. In addition readers are referred to suites of papers in volumes 5,12 and 19 of
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APPENDICES
APPENDIX I
INSTITUTIONAL INFRASTRUCTURE AND CAPACITY
Human capacity
Hempel and Haslund (1997) have provided a comprehensive assessment of the state of
marine science and science capacity in Angola. The Instituto de Investigacao Pesqueira
(IIP) is the central institute for basic marine environmental and fisheries research. With a
total staff of about 220, of which approximately 40 are university trained, IIP's primary
focus is on the monitoring, research and assessment of the fish resources per se. The
environmental (oceanography) component of IIP comprises 14 staff members, engaged in
various aspects of fisheries oceanography, environmental monitoring and pollution
control. The policy of IIP is to increase the skill level of staff, and considerable success
has been achieved through close collaboration with the Agostinho Neto University in
Luanda and other SADC universities (e.g. University of Cape Town) as well as with
universities in Europe, principally in Russia, Germany and Norway. Participation in IOC-
sponsored and BENEFIT training initiatives is likewise proving to be beneficial. In spite
of difficult operating conditions, with severe limitations in terms of equipment and
infrastructure, IIP staff do not lack initiative and enthusiasm, and this bodes well for the
future. Donor support from countries such as Norway, Germany and Sweden to strengthen
human capacity has been and continues to be vital.
Namibia has a long tradition in marine science and technology, and following
independence in 1990, the government has placed a strong emphasis on the training of
Namibians and the development of local expertise. The Ministry of Fisheries and Marine
Resources (MFMR) is the agency responsible for monitoring, research, assessment,
management and control of living marine resources within Namibia's EEZ. The
monitoring, research and assessment component, which will be referred to loosely as
"research" is headed by a Director based in Windhoek and with most research staff located
in Swakopmund at the National Marine Information and Research Centre (NatMIRC). A
smaller research group is based in Lüderitz. MFMR has a research and support staff
complement of about 100 persons of whom approximately 40 have four-year or higher
university qualifications. On paper the "environmental research" component comprises 9
research posts and two technical positions. Recent restructuring within the Ministry in
order to strengthen capacity to address pressing fishery monitoring and assessment
problems, has de facto resulted in a substantial shrinkage of the oceanography group,
although the Ministry is evidently taking steps to redress this. The environmental group,
although small, has since independence embarked on a comprehensive monitoring
programme, and through close collaboration with, and with strong support from
Norwegian and German scientists developed a high degree of competence. (This is
reflected in the large number of reports and publications which have been produced by the
oceanographers during recent years). Several of MFMR staff have post-graduate
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qualifications gained at overseas and SADC universities, and like IIP, MFMR has a strong
education and training policy. The advent of BENEFIT is enabling further development of
Namibian marine science capacity. The Ministry has wisely decided to make maximum
use of remotely sensed marine environmental data, and is currently developing appropriate
skills to utilise and interpret these. There remains, however, a shortage of technical posts
and trained oceanographic technicians. The University of Namibia (UNAM) has a close
association with MFMR and is keen to develop collaboration training courses in
oceanography and fisheries science. UNAM does not yet offer post-graduate degree
courses in marine science.
South African marine science celebrated its centenary in 1995, and can generally be
considered as world class. The Marine and Coastal Management (MCM) of the
Department of Environmental Affairs and Tourism, based in Cape Town has a total
research staff complement of about 150, of whom approximately 50 are university
graduates. The support staff comprise highly skilled engineers, technicians and technical
assistants. All of the technicians possess formal technical qualifications (NDT
oceanography) or similar equivalent to a three year university degree). The majority of
the research staff possess post-graduate degrees. MCM has a long and close association
with the University of Cape Town (UCT) and other South African universities, and also
since the early 1960s, with the Cape Technikon. Approximately 20 oceanographers and 20
technical staff at MCM are involved in environmental or ecosystem-type research or
monitoring, and are divided into "Environment" and "Whole Systems" groups. These
provide the disciplinary homes for physical oceanographers, marine chemists,
planktologists, ecosystem-expert and modellers. Scientific output as evident in
publications in international scientific journals and by way of management advice is high,
comparable with leading marine institutes in Europe and North America. Apart from
MCM, staff and students of several departments at UCT and the University of the Western
Cape (UWC), employees of the South African Museum, CSIR, Institute of Marine
Technology inter alia are engaged in research and monitoring of various aspects of the
Benguela environment. At UCT, for example, four full time academic appointees in the
Oceanography Department and two in the Zoology Department can be regarded as
specialists on the Benguela ecosystem. In addition, the Zoology Department has a long
tradition and considerable expertise in inshore ecology. The highly regarded Benguela
Ecology Programme served as the principal catalyst for the development of Benguela
environmental expertise in South Africa during the 1980s. BENEFIT and BCLME have
the potential to do the same for the three countries of the Benguela region over the next
few decades.
Infrastructure
(a) Accommodation
The accommodation available for marine science and technology in the region is generally
good. In Angola, the headquarters of IIP in Luanda are housed in a large modern building
equipped with six laboratories for fisheries/oceanography and food technology, 60 offices
for administration staff and scientists, a library and three meeting rooms. Regional
offices/laboratories exist in Benguela, Lobito, Namibe and Tombua. (The accommodation
at Namibe is new and well designed, and is situated near the harbour. Namibe is likely to
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be an important centre in Angola for BENEFIT and BCLME activities.) The Agostino
Neto University is located in the centre of Luanda. Buildings are in poor condition.
Office and laboratory facilities in Namibia exist at NatMIRC in Swakopmund and in
Lüderitz. The former are modern of a high standard, and provide a good working
environment for Namibia's marine and fisheries research. Meeting facilities are excellent.
Overall the accommodation is very good. The Lüderitz facility is smaller, but has recently
been upgraded and is also regarded as very good. The University of Namibia is housed in
modern buildings on the outskirts of Windhoek. Office/laboratory accommodation ranges
from adequate to excellent.
In South Africa MCM is housed in a commercial building close to the Cape Town city
centre. Although not ideal in layout (design) the offices and laboratories are of a relatively
high standard and provide a generally satisfactory working environment for MCM staff.
Meeting facilities are good and there is a small multi-purpose auditorium. The University
of Cape Town is situated 4km away at Rondebosch. Offices and laboratoriums in the
Zoology and Oceanography Departments are good. Lecture and seminar rooms provide
good venues for meetings and conferences. Excellent library facilities exist at MCM and
UCT. The CSIR is situated at Stellenbosch, some 50km from Cape Town. Office and
laboratory accommodation there is excellent. The University of the Western Cape is at
Bellville, about 20km from Cape Town. Office and laboratory accommodation at UWC is
good.
(b) Research Ships
Angola: R. V. Goa. Small, poorly equipped, and not operational
Namibia: R. V. Welwitschia (47m). Modern multi-purpose research stern trawler built in
1994, carries a maximum of 9 scientists, although accommodation for only 5 can be
regarded as satisfactory. Laboratories are small. The vessel is not ideally suited to use on
multi-disciplinary fish-environment surveys. R. V. Kuiseb (19m). General purpose
wooden vessel built in 1958, carries 4 scientists. A very basic replacement is under
construction.
South Africa: F. R. S. Africana (78m). Modern all weather multi-purpose fisheries and
oceanography research stern trawler built in 1981. Excellent laboratories. Carries 17
scientists. F. R. V. Algoa (53m). Converted commercial stern trawler, with similar
capabilities, but on a lesser scale, to Africana . Carries 12 scientists. F. R. V. Sardinops
(37m). Old (1958) research side trawler. Limited capability. Carries 4 scientists. The
manning arrangements for South African research vessels are problematic.
Norway: R. V. Dr Fridtjof Nansen (78m). Modern multi-purpose fisheries stern trawler.
Excellent. Carries 17 scientists. The vessel built in 1992 replaced the previous one of same
name which had been operating in the South-east Atlantic since the late 1980s. This is
probably the most versatile and useful vessel in the region and the cornerstone of fisheries
research (surveys) off Namibia and Angola.
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Germany: Although there is no German research ship dedicated to the region, Germany
chartered a vessel in 1997 for the investigation of the Angola/Benguela front, and plans to
charter vessels for work in the Benguela ecosystem again in the future.
(c) Equipment/Instrumentation
Except R. V. Goa, R. V. Kuiseb and F. R. V. Sardinops, the research ships are well
equipped and possess modern instrumentation and gear. In the case of South Africa much
of the instrumentation has been locally developed (a result of sanctions) and has during the
past five years become run-down as a consequence of shrinking budgets and increased
operating costs. Shore-based laboratory facilities in terms of instrumentation and
equipment in South Africa and Namibia range from adequate to excellent. The Angolan
laboratories are generally poorly equipped, with very limited instrumentation. The
supporting infrastructure is likewise totally inadequate. A satellite communication link
with IIP in Luanda has recently been established.
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APPENDIX II
OCEANOGRAPHIC AND FISHERIES DATA AND INFORMATION SYSTEMS
Angola
There are four separate fisheries data processing systems in operation in Angola: one system is
based at the Fisheries Research Institute (IIP), one is in the Directorate of the National Fisheries
(DNP), one is at the Directorate of Surveillance (DNF), and there is a system used by the Planning
Office in the Ministry of Fisheries (GEP).
The DNP system has been developed through Swedish support and is based on the Swedish Baltic
Sea fisheries data system. It is used for commercial fisheries statistics. The version in use in the DNP
has been modified to meet local needs, but is as yet incomplete. The system enables the registration
of fishing companies, catch discharges, gear and species data, registration of gear in use in the
fishery. These data are available for both national, joint venture and foreign fishing vessels and
companies. The system also facilitates the registration of fishing enterprises, taxes, contracts, export
data and transhipment details. The analysis output is limited at present but the intention is to access
and output details on quotas and TACs. Exchange rate updating will be included so that values can
reflect local currency fluctuations. The DNP has three MS-Dos Windows based PCs which are as yet
unlinked. A small dedicated computer network has recently been purchased. created to deal
specifically with the database, with its own personnel and resources.
Angola has recognised that there needs to be a unified data system and has proposed modifying the
DNP system so that more detailed analysis for stock and catch assessment can be achieved. A
programme to unify the systems has been devised, and this will be done in conjunction with an
upgrading of the data collection system. IIP is developing its own database for fisheries and
oceanographic scientific data. A new section in IIP has been created to deal specifically with the
database, with its own personnel and resources. The oceanographic data still need to be incorporated
in the database. A major task will be to recover and include the historic records which span nearly 30
years.
Apart from oceanographic data collected by Angola e. g. a 30 year time series of sea surface
temperature, salinity and oxygen at Lobito and other pre- and post-independence records, IIP has a
comprehensive set of data from the monitoring and research programme. IIP also holds Russian data
sets on the oceanography of the Angola/Benguela front and Angola Dome, while more data sets rest
in Kaliningrad.
Namibia
The Ministry of Fisheries and Marine Resources has developed and implemented an integrated
Fisheries Information Management System that provides a data capture, information management
and reporting system for all core information on the fisheries sector. The FIMS provides for the
following modules; Species, Vessels, Factories, Fisheries, Exploitation Rights, Quotas, Payments,
Landings, Logsheets and a Management Information System (MIS). This core system is designed to
manage all information from and to the fishing industry. Work is also well advanced in the
development of two further sub-systems: the Biological, Oceanographic and Supporting Research
Module (BOSRM) and the Surveillance and Enforcement Module (SEM). The overall system will thus
provide access to the full range of information available tot the Ministry, including all available
historical data and international databases. The BOSRM will provide access to, and be integrated
with, fisheries sector information to enable accurate and meaningful analysis and interpretation of
catch information against fishery and environmental dynamics. However, delays in the
implementation of BOSRM mean that there is no viable oceanographic data base available to MFMR
scientists, and data are currently stored on disk and hard copy.
It is planned that all information, subject to confidentiality and security, will be made available for
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research and general use by government, industry, international collaborating partners and agencies
through a variety of systems of access.
The system was developed using S-Designer and Powerbuilder and is implemented using
Microsoft NT and SQL Server in a Windows 3.1 and 95 environment. There are four sites
each with their own server networks at Windhoek (Ministry of Fisheries and Marine
Resources HQ), Swakopmund (National Marine Information and Research Center),
Walvis Bay (Inspectorate and Operations Centre) and Lüderitz (Inspectorate and
Research). These four LANs are connected by a WAN through a leased line system on
fibre-optic cables and all network management is from the Information Systems Division
in Windhoek. The majority of hardware has been specifically purchased for the designed
task (Olivetti servers and work stations) but with a view to appropriate expansion
particularly of storage and processing power.
Namibian oceanographic data holdings, pre-and post-independence, including extensive
data collected during cruises of the Dr Fridtjof Nansen during the 1980s and 1990s and
during cruises of R. V. Welwitschia and R. V. Matsuyama Maru (Japanese Overseas
Fisheries Cooperation Foundation), are extensive and generally of a high quality. Cruise
data are augmented by data from coastal monitoring stations (Swakopmund and Lüderitz)
and satellite imagery.
South Africa
(a) MCM has been using the Data General range of mini computer since 1979 for the
processing of data relating to commercial catches, research samples and environmental
parameters. The applications were developed in Cobol and the data stored in an Infos
hierarchical database. These systems are currently being converted in order to make
use of the advanced features offered by new hardware and software technology. These
applications will be run on a local area network using Novel NetWare. The data are
being converted to a relational database which will support the integration of common
entities, such as grids, vessels and species codes, and provide better facilities for ad
hoc management and research queries. The software is being developed using Borland
Delphi, a fourth generation language which runs on PCs using Windows 95. The bulk
of the systems relate to commercial catches from the following sectors: Demersal,
Pelagic, Rock Lobster, (West Coast, South Coast and Natal), Abalone, Linefish and
Netfish. Some data sets cover catches from 1978 to date. The environmental
parameters (physical and chemical0 and stored in the Oceanographic Database. The
issuing of vessel licences and fishing permits is handled by the Boat Registration
System.
(b) The University of Cape Town is well connected in the academic and research
environments in Southern Africa. Not only does the University have a wide range of
computers available, from Macs to PCs to Workstations, but it has expertise that is of
world class quality. All of the University computers are connected to the Internet as
well as on several local area networks on campus. The University is constantly seeking
to upgrade and improve the quality of this interconnectivity so as to increase the flow
of information. Through the Centre of Marine Studies and the various Departments at
the University, expertise is readily available in the fields of data processing and
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statistics, resource assessment, management and conservation as well as environmental
evaluations and oceanographic remote sensing. These skills can be applied to the
problems of data and information management as well as in the interpretation,
presentation and publication of the necessary data.
(c) South Africa possesses an extremely comprehensive collection of oceanographic data;
discrete, profile and time series. Most of these are available from SADCO (see below)
and/or MCM. South Africa also has extensive holdings of NOAA satellite sea surface
temperature data.
South African Data Centre for Oceanography (SADCO)
SADCO was established as a national oceanographic data bank in the 1970s to service
South Africa's marine science community. It has subsequently developed into a regional
facility. SADCO archives, extracts and manipulates oceanographic data from the southern
African marine environment and provides a spectrum of professional cost-efficient and
user-friendly services. It also promotes the scientific and commercial application of
oceanographic data.
SADCO receives data for the area 0°-70°S and 30°W-70°E from a variety of sources including various
southern African marine agencies, and World Data Center, and other international data sources by
exchange or purchase.
The SADCO data base contains observations since 1850 which include inter alia the
following:
Oceanographic station data for surface and serial depths, giving values of
temperature, salinity, sound velocity, oxygen, nutrients etc.
Digital bathythermograph and XBT data
Surface data from voluntary observing ships (VOS) including waves, wind and
weather, comprising some 3 million readings
SADCO also has access to various document information systems which enable literature
searches for published oceanographic data
SADCO is guided by a Steering Committee and managed by CSIR on behalf of its sponsors which
include the South African Department of Environmental Affairs and Tourism, the South African Navy,
CSIR, Foundation for research Development and the Namibian Ministry of Fisheries and Marine
resources. Service charges are modest. SADCO could play an important role in BCLME.
Data Confidentiality/Restrictions
Most oceanographic data collected by regional scientists/research institutions is generally
available to other bona fide scientists subject to certain conditions. These conditions
include inter alia appropriate acknowledgement of data ownership, a time clause to give
the owner a reasonable period to analyse the data and publish research results.
Oceanographic collected in international waters around southern Africa by overseas
oceanographic institutes is likewise generally readily available to scientists and
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technicians in southern African states. Again the principals and ethics of international
science and/or intellectual property rights apply. For example, SADCO receives and
archives various forms of oceanographic data but can put a limited-period hold on data if
requested by the collector of the data to do so. These data would then not be released to a
third party during the embargo period unless authorised by the data owner, but the data
could be used with other data in the data-base for averaging purposes. The present system
works well.
Resource-based data are, however, in a different category and fisheries data may not be readily
available outside of the organisation responsible for its collection. This practice is not peculiar to
southern Africa and applies almost universally. There are two main reasons for this viz. (a)
commercially sourced fisheries data contains information which may give the supplier (fisherman or
fishing company) a competitive edge over rivals and (b) raw fisheries data may be regarded as
strategic information by management agencies and national governments. Fisheries data are,
however, generally readily available in processed form. Nevertheless the fact remains that most
fisheries and oceanographic data are collected by, or at the behest of, organisations funded by
national tax payers and there is a universal movement towards increased transparency and
accountability of governments.
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APPENDIX III
LIST OF PERSONS CONSULTED
The major part of this Overview was prepared at the University of Cape Town. It draws on input from a
large number of individuals, by way of written documents (reports, publications), or from
presentations at symposia and workshops (e. g. International Symposium and Workshop on
Environmental Variability in the South-east Atlantic, Swakopmund, March/April 1998; First Regional
Workshop on BCLME, Cape Town, July,1998) and from discussions with key role players. The
persons consulted specifically for the Overview were as follows:
Dr J. Augustyn (Acting Director, MCM)
Dr L. Hutchings (Chief Specialist Scientist, MCM and Member: BCLME Management Committee)
Dr M. J. O'Toole (MFMR, and BCLME Project Coordinator)
Mr G. W. Bailey (MCM)
Dr R. G. Barlow (MCM)
Dr A. Cockcroft (MCM)
Dr R. J. M. Crawford (MCM)
Dr J. David (MCM)
Prof. J. Field (Zoology Department, UCT)
Dr V. Filipe (IIP)
Mrs P. Krohn, (Oceanography Department, UCT)
Prof. J. R. E. Lutjeharms (Oceanography Department, UCT)
Dr V. de Barros Neto (IIP)
Dr A. Pereiro (IIP/BENEFIT)
Dr S. Pillar (MCM)
Dr G. Pitcher (MCM)
Dr M. de Lourdes Sardinha (IIP)
Ms L. J. Shannon (MCM)
Prof. F. Shillington (Oceanography Department, UCT)
Mr A. P. van Dalsen (MCM)
Dr H. Verheye (MCM)
Dr H. Waldron (Oceanography Department, UCT)
Mr B. Wessels (MCM)
Drs P. Freon, P. Curie and C. Roy (ORSTOM, seconded by the French Government to
work in the Benguela region 1998-2000)
In addition to the above, discussions were held with key staff of MFMR in Namibia as part of a
separate contract in 1997/1998 funded by The World Bank with the purpose of developing an
environmental strategy for MFMR. The principal individuals consulted during this exercise were:
Dr B. Oelofsen (Director: Resource Management MFMR)
Dr. B. van Zyl (Deputy Director: Applied Research MFMR)
Ms J. Botha (MFMR)
Mr C. Bartholomae (MFMR)
Ms A. Risser (MFMR)
Ms K. Noli-Peard (MFMR)
Mrs B. Currie (MFMR)
Mr C. Beyers (MFMR)
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Mr A. Kemp (MFMR)
Dr G. Ohe (GTZ)
Dr M. F. Tejedor (seconded to MFMR by Spanish Government)
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APPENDIX IV
ACRONYMS
AABW
Antarctic Bottom Water
AAIW
Antarctic Intermediate Water
BCLME
Benguela Current Large Marine Ecosystem
BENEFIT Benguela-Environment-Fisheries-Interaction-Training (Programme)
BEP
Benguela Ecology Programme
CZCS
Coastal Zone Colour Scanner
EEZ
Exclusive Economic Zone
ENSO
El Niño Southern Oscillation
EU
European
Union
FRD
Foundation for Research Development (South Africa)
GDP
Gross
domestic
Product
GEF
Global Environmental Facility (World Bank)
GLOBEC
Global Ocean Ecosystem Dynamics
GTZ
Deutsche Gesellschaft fur Technische Zusammenarbeit
ICEIDA
Icelandic International Development Agency
IGBP
International Geosphere-Biosphere Programme
IHDP
International Human Dimensions Programme
IIP
Instituto de Investigaçao Pesqueira (Angola)
IOC
Intergovernmental Oceanographic Commission
MCM Marine and Coastal Management (South Africa)
MFMR
Ministry of Fisheries and Marine Resources (Namibia)
NatMIRC
National Marine Information and Research Centre (Namibia)
NORAD
Norwegian Agency for Development Cooperation
PDF
Programme Development Fund (of GEF)
RV/S
Research Vessel/Ship
SADC
Southern African Development Community
SADCO
South African Data Centre for Oceanography
SANCOR
South African Network for Coastal and Oceanic Research
SAP
Strategic Action Plan
SeaWiFS
Sea-viewing Wide Field-of-View Sensor
SFRI
Sea Fisheries Research Institute (South Africa)
SIDA
Swedish International Development Agency
SPACC
Small Pelagic Fish and Climate Change Programme (of GLOBEC)
SST
Sea Surface Temperature
STSW
Subtropical Surface Water
TAC
Total Allowable Catch
TW
Thermocline
Water
UNAM
University of Namibia
UCT
University of Cape Town
UNESCO
United Nations Education, Scientific and Cultural Organisation
UWC
University of the Western Cape
WCRP
World Climate Research Programme
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APPENDIX V
NOTES ON ANGOLAN OCEANOGRAPHIC CRUISE AND DATA
REPORTS AND PUBLICATIONS
MR A. F. PEREIRA, A MEMBER OF THE SCIENTIFIC STAFF OF IIP WHO IS CURRENTLY
ON SECONDMENT TO THE BENEFIT SECRETARIAT, WAS COMMISSIONED TO COMPILE
INFORMATION ABOUT OCEANOGRAPHIC CRUISES UNDERTAKEN IN ANGOLA'S EEZ
AND TO EXTRACT PERTINENT INFORMATION FROM THE VARIOUS CRUISE AND DATA
REPORTS AND PUBLICATIONS. IN COLLABORATION WITH IIP STAFF, IN PARTICULAR
MR V. L. L. FILIPE, MR PEREIRA PRODUCED A COMPREHENSIVE DRAFT DOCUMENT
WHICH CONTAINS A WEALTH OF INFORMATION RELEVANT TO BCLME, AND WHICH
WILL BE EXTREMELY USEFUL FOR PLANNING PURPOSES. THE FOLLOWING IS A
SHORT COMMENT ON THE AVAILABLE INFORMATION AND ITS POTENTIAL UTILITY.
Since 1985, the R. V. Dr Fridtjof Nansen has undertaken numerous surveys of Angola's
fish resources in collaboration with IIP. During these cruises environmental measurements
(e.g. temperature, salinity, dissolved oxygen, plankton, currents etc) were made. Some 18
cruise reports spanning the period 1985-1998 are now available, and these contain
information about the various parameters measured, and useful comments on the state of
the environment by the compiler, key extracts of which are contained in Mr Pereira's
report ("pertinent comment by compiler"). Apart from the R. V. Dr Fridtjof Nansen,
cruises were also undertaken by Angola's R. V. Goa and various other research vessels
Russian, Portuguese, Cuban etc. Eleven cruise reports emanating from the R. V. Goa and
nine from other vessels are available.
Since Independence, IIP scientists have authored 17 environmental scientific papers. These are
mostly in Portuguese, but a number of recent articles are in English. Although it has not been
possible in view of time limitations to undertake a comprehensive assessment of these publications,
it is clear from the information provided by Mr Pereira that as a set they do provide a valuable
addition to the literature on the Benguela ecosystem. What is also apparent is that IIP scientists,
drawing on this material and their knowledge of the Angolan marine environment, will be able to make
a substantial contribution to the execution of the BCLME during the implementation phase.
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CONTENTS
1 Introduction
1
2
Physical features and processes
2
2.1
Bathymetry 2
2.2
Winds
3
2.3 Upwelling and surface temperature
4
2.4 Water masses and general circulation
6
2.5
Shelf
circulation
9
2.6 System boundaries, fronts and filaments
10
3
Chemistry and related processes 13
3.1 Dissolved oxygen 14
3.2 Nutrients
15
3.3 Sulphur 17
3.4 Other aspects of marine chemistry 18
4
Plankton and the foodweb
19
4.1 Phytoplankton and primary production
19
4.2 Red tides and harmful algal blooms
21
4.3 Zooplankton and secondary production
23
4.4 Foodweb and carbon budget
25
5
Environmental variability
26
5.1 Small-scale variability
27
5.2 Seasonal changes and intra-annual variability
28
5.3 Interannual variability and episodic events
29
5.4 Decadal changes and regime shifts
33
5.5 Recent developments
34
6
Issues, problems, threats and gaps in knowledge
35
6.1 Fundamental issues
35
6.2 Environmental variability
36
6.3 The Benguela and global environmental(climate) change
37
6.4 Gaps in knowledge and understanding
38
6.5 Infrastructure and human capacity
39
6.6 Funding
40
7
Acknowledgements
41
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163
8
References
41
Appendix I Institutional infrastructure and capacity
49
Human capacity
49
Infrastructure
50
Appendix II Oceanographic and fisheries data and information systems 53
Angola 53
Namibia 53
South Africa 54
South African Data Centre for Oceanography (SADCO) 55
Data confidentiality/restrictions 56
Appendix III List of persons consulted 57
Appendix IV Acronyms 59
Appendix V Notes on Angolan oceanographic cruise and data reports 60
and
publications
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FIGURE CAPTIONS
Fig. 1 Locator map and principal bathymetric features of the Benguela region
Fig. 2 Monthly windstress along the west coast of southern Africa, 75km offshore
(modified from Boyd 1987). Note the windy areas near Lüderitz and Cape Frio and
the pronounced seasonality in the south
Fig. 3 Conceptual picture of wind-induced coastal upwelling (modified from Shannon
1989)
Fig. 4 Satellite-derived sea surface temperature distribution in the southern Benguela, 9
October 1997
Fig. 5 Characteristic temperature-salinity relationships for the South-east Atlantic Ocean
and Benguela region
Fig. 6 Vertical east-west sections at three locations in the Benguela, illustrating the
depths of principal water masses, viz Tropical Surface Water (TSW), Subtropical
Surface Water (STSW), Thermocline Water (TW), Antarctic Intermediate Water
(AAIW), North Atlantic Deep Water (NADW) and Antarctic Bottom Water
(AABW). Note the absence of AABW in the area north of the Walvis Ridge, and
the strongly stratified surface layer off Angola
.
Fig. 7 Physical boundaries of the Benguela and surface (upper layer) currents
Fig. 8 Satellite-derived sea surface temperature distribution in the northern Benguela,
10 April 1997
Fig. 9 Conceptual diagram showing location of zones of formation of oxygen poor water
in the South-east Atlantic
Fig.10 A two-dimensional network of nitrate (and hence carbon) pathways between
ocean, shelf and sediments. Numbers are grams carbon x 1013 . (Courtesy Dr H.
Waldron, Oceanography Department, University of Cape Town)
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165
Fig. 11 Ocean colour image showing chlorophyll distribution in the Benguela obtained
by SeaWiFS satellite, 9 March,1998 Courtesy NASA and Ocean Space CC
Fig. 12 Bloom of red tide organism Noctiluca scintilans in the southern Benguela
(Courtesy D. Horstman, SFRI)
Fig. 13 Diagram showing partitioning of planktonic food between sardine and anchovy
(from Van der Lingen 1994)
Fig.14 Southern Benguela upwelling foodweb models (a) Rythers (1969) model and (b)
a revised more appropriate model incorporating the microbial foodweb (from
Moloney 1992)
Fig.15 Distribution of sea surface temperature in the northern Benguela, early in 1984,
showing the southward penetration of warm water during a Benguela Niño
(NOAA image generated by and reproduced courtesy of Ms Scarla Weeks,
Oceanography Department, University of Cape Town)
Fig.16 Mass mortality of rocklobsters at Elands Bay in the southern Benguela as a
consequence of the appearance of oxygen deficient water (Courtesy Dr A.
Cockcroft, SFRI)
Fig.17 The "Great Ocean Climate Conveyor Belt" (modified from Broecker, 1991)
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AN OVERVIEW OF THE SOCIO-ECONOMICS OF SOME KEY
Chris
Tapscott
A
Report
Prepared
on Behalf of the
Benguela Current Large Marine Ecosystem Project
Windhoek, October 1999
167
Table of Contents
Page
1.0 Background ..................................................................................................................1
2.0
Objectives of the Study................................................................................................1
3.0
Terms of Reference ......................................................................................................1
4.0 Methodology .................................................................................................................2
5.0
The Social Economy of the Benguela Current Region - An Overview ...................2
6.0 Angola ...........................................................................................................................4
6.1
Demography and Settlement Patterns............................................................................4
6.2 Social
Services ...............................................................................................................6
6.3 Physical
Infrastructure ...................................................................................................7
6.4 Fisheries .........................................................................................................................8
6.5 Diamond
Mining............................................................................................................9
6.6 Oil
and
Gas ..................................................................................................................10
6.7
Other Economic Activity .............................................................................................10
6.8 Development
Potential.................................................................................................11
7.0 Namibia.......................................................................................................................13
7.1
Demography and Settlement Patterns..........................................................................13
7.2 Social
Services .............................................................................................................18
7.3 Physical
Infrastructure .................................................................................................18
7.4 Fisheries .......................................................................................................................19
7.5 Diamond
Mining..........................................................................................................21
7.6 Oil
and
Gas ..................................................................................................................23
7.7
Other Economic Activity .............................................................................................23
7.8 Development
Potential.................................................................................................24
8.0 South
Africa................................................................................................................25
8.1
Demography and Settlement Patterns..........................................................................25
8.2 Social
Services .............................................................................................................27
8.3 Physical
Infrastructure .................................................................................................28
8.4 Fisheries .......................................................................................................................29
8.5 Diamond
Mining..........................................................................................................31
8.6 Oil
and
Gas ..................................................................................................................33
8.7
Other Economic Activity .............................................................................................33
8.8 Development
Potential.................................................................................................34
9.0
Threats to the BCLME Policy Issues ....................................................................34
10.0 Individuals
Interviewed.............................................................................................39
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168
11.0 Bibliography ...............................................................................................................40
11.0 Maps
Map 1. The BCLME Study Area ..................................................................................3
Map 2. The Coastline of Angola Indicating Provincial Boundaries..............................5
Map 3. The Coastline of Namibia Indicating Regional Boundaries............................14
Map 4 The West Coast of South Africa from Alexander Bay to Lamberts Bay .........26
Map 5. The West Coast of South Africa from Lamberts Bay to Cape Agulhas..........27
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ANNEX N
BENGUELA CURRENT LARGE MARINE ECOSYSTEM
STAKEHOLDERS
GROUP 1
Sustainable Management and Utilization of Resources
Ministeries Responsible for :-
Fisheries
Environment
Tourism
Transport
Mining
Energy
Finance
Private Sectors:-
Fishing Companies
Mining Companies
Oil and Gas (Offshore Exploration and Production) Companies
Tourism Companies
Others:-
International Donor Agencies
Relevant NGO's
Research Institutions and Universities
Coastal Communities
Interested Individuals
GROUP 2
Environmental Variability
Ministries Responsible for :-
Fisheries
Environment
Tourism and Health
Finance
Mining
Energy
Works, Transport and Communication
Private Sectors:-
Fishing Companies
Mining Companies
Oil and Gas (Offshore Exploration and Production) Companies
Tourism Companies
Others:-
International Donor Agencies
Relevant NGO's
Research Institutions and Universities
Coastal Communities
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170
Municipalities
Port Authorities
Meteorological Services
Interested Individuals
GROUP 3
Ecosystem Health and Pollution
Ministeries Responsible for:-
Fisheries
Environment
Energy
Mining
Health
Tourism
Finance
Defence
Immigration
Police
Transport and Communication
Trade
Private Sectors :-
Fishing Companies
Mining Companies
Oil and Gas (Offshore Exploration and Production) Companies
Tourism Companies
Shipping Companies
Others:-
International Donor Agencies
Relevant NGO's
Research Institutions and Universities
Port Authorities
Municipalities
Meteorological Services
Coastal Communities
Interested Individuals
Brief Description of PDF-B Involvement
The seed for the BCLME Program was sown at a workshop/seminar held in Swakopmund, Namibia in mid-
1995. This paved the way for the development of a PDF Block B Grant Proposal to GEF, and its subsequent
approval and implementation in 1998. In July 1998 the First Regional BCLME Workshop, attended by
approximately 100 stakeholders and regional and international experts, was held in Cape Town, followed by
a formal meeting of key stakeholders. The attendance and proceedings of this workshop are attached to this
document as Annex 9.
Stakeholders have and will continue to include the ministries in Angola, Namibia and South Africa
responsible for the environment, marine resources, mines, energy, tourism, science and technology,
transport, ports and harbours, etc.; representatives of relevant industry sectors such as diamond mining,
fishing (including artaisanal fishers), oil and gas (e.g. SONANGOL from Angola); education and training
establishments - universities and technikons; regional and local authorities and NGOs. The lead stakeholders
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171
are: Ministry of Fisheries and Marine Resources, Namibia; Ministries of Fisheries and Environment,
Angola; Department of Environmental Affairs and Tourism, South Africa.
The First Regional Workshop identified the issues and problems/constraints in the BCLME and possible solutions. As a
follow-up, six comprehensive syntheses and assessments of information on the BCLME (thematic reports) were produced,
viz: fisheries, oceanography and environmental variability, diamond mining, coastal environments, off-shore oil and gas
exploration/production, socio-economics. These reports were reviewed at the Second Regional BCLME Workshop held in
Namibia in April 1999, and used as a basis together with input from the First Workshop and participants for drafting the
TDA and setting the SAP framework. Actions subsequently have led to the finalisation of the TDA, SAP, Project Brief and of
the BCLME Program.
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