BCLME Project: LMR/NANSEN/02/05 Cruise reports "Dr. Fridtjof Nansen"
BCLME SURVEY NO. 2 2005
A TRANSBOUNDARY STUDY OF THE PELAGIC FISH STOCKS OF SOUTHERN
ANGOLA AND NORTHERN NAMBIA
Cruise report No 2/2005
13 23 August 2005
by
Filomena Vaz-Velho1), Martha Uumati2), Helvi Mupupa2), Bjørn Erik Axelsen3) and Diana Zaera3)
1) Instituto Nacional de Investigação Pesqueira
Luanda, Angola
2) National Marine Information and Research Centre
Swakopmund, Namibia
3) Institute of Marine Research
Bergen, Norway
Bergen, 2006
TABLE OF CONTENTS
Summary.................................................................................................................... 2
Acknowledgements .................................................................................................... 4
List of Abbreviations ................................................................................................... 4
1 Introduction .......................................................................................................... 5
1.1 Objectives .................................................................................................... 6
1.2 Participation ................................................................................................. 7
1.3 Survey schedule .......................................................................................... 7
1.4 Survey effort................................................................................................. 8
2 Materials and methods....................................................................................... 11
2.1 Acoustical sampling ................................................................................... 12
2.2 Trawl sampling procedures ........................................................................ 15
2.3 Meteorological and hydrographical sampling ............................................. 16
3 Results............................................................................................................... 16
4 Oceanographic Conditions................................................................................. 23
5 Conclusion and recommendations ..................................................................... 28
6 References ........................................................................................................ 30
Annex I Records of fishing stations ......................................................................... 31
Annex II Catch rates................................................................................................. 36
Annex III Length weight relationships, gonad maturity and length distribution ........ 37
Annex IV Instruments and fishing gear.................................................................... 40
Annex V Seabirds and Mammals ............................................................................. 42
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Summary
The study has demonstrated that studied species are to large extents transboundary in the
cold season and underpin recent reports of alarmingly low abundance levels of Cunene
horse mackerel and sardine. Cunene horse mackerel was found as far south as Cape Frio
(19º00' S), but the densities found south of the Angolan-Namibian border were too low to
substantiate any kind of biomass estimation. The biomass of Cunene horse mackerel in
Angola was 44 000 tons. Cape horse mackerel were found throughout the transboundary
area. The biomass was 253 000 tons (64 %) in Angolan waters and 140 000 in Namibian
waters (36 %), i.e. 393 000 tons in total.
Scattered individuals of sardine (pilchard) were found in some of the samples on both sides
of the border during the high-density search grid for clupeids, but no aggregations of sardine
were recorded, neither acoustically nor with the sampling gear (pelagic sample trawls). Any
sizeable aggregation in the area would almost certainly have been discovered during such
an intensive surveying exercise and it is therefore concluded that no sizeable aggregations
of sardine were present in neither in Angola nor the transboundary area at the time of the
survey. Other clupeid species (round herring and anchovy) were only found in scattered,
low-density aggregations insufficient to produce any estimates of abundance.
All target species were found in small size groups. Cunene horse mackerel was generally
less than 25 cm, and for Cape Horse mackerel 80% of the fish were less than 15 cm total
length. The little that was found of the various clupeids was generally, small size groups.
The main recommendations are:
1
The survey should be repeated at the same of the year in order to establish whether the
observed pattern is persistent over time and to monitor development trends in the
transboundary area over time, if any.
2
The investigation should also be conducted in the warm season. The distribution pattern
of all species under investigation here will likely be quite different in the alternate
season. Horse mackerel distributions over the transboundary area generally follow the
position of the Angolan-Benguelan front (ABF), i.e. both species have more southern
distribution in the warm season. This will, in turn lead to expectations of more Cunene
horse mackerel in Namibian waters and less Cape horse mackerel in Angolan waters
during summer.
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3
The two countries involved should consider cooperating on continuing to monitor the
transboundary area and to coordinate management of the fish resources there; all
stocks under study here are to some extent transboundary and most stocks are in low
abundance. Only fish smaller than 25 cm were found throughout the transboundary
area.
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Acknowledgements
A special thank goes to the officers and crew on the R/V `Dr Fridtjof Nansen' for their efforts
and good cooperation at sea.
List of Abbreviations
Parameter Name
Units
i
Estimated number of fish in length group i
ABF Angola-Benguela
Front
ADCP
Acoustic Doppler Current Profiler
As
Horizontal area of stratum s
[m2]
BT
Bottom Trawl (demersal)
CF
Correction Factor
CTD
Conductivity, Temperature and Density
CF Condition
Factor
CV
Coefficient of Variance
DO
Dissolved Oxygen
[ml l-1]
Li
Length group i
[cm]
LT
Local Time (= UTC + 1 hour)
n.mi
Nautical miles = 1852 m
PT Pelagic
Trawl
S Salinity
sA
Area backscattering coefficient
[m2 n.mi-2]
SSS
Sea Surface Salinity
SST
Sea Surface Temperature
[°C]
SV
10 log(sv)
[dB re 1 m-1]
T Temperature
[°C]
ti,j
Proportion of species j sampled in length group i
TS
Target Strength
[dB re 1 m2]
ui
Proportion of fish sampled in length group i
UTC
Greenwich Middle Time (earlier GMT)
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1 Introduction
This transboundary pelagic survey is a dedicated research survey covering the pelagic fish
resources and hydrographical conditions in the region ranging from southern Angola to
northern Namibia. The main focus of the work was to assess the biomass of all commercially
important pelagic fish stocks in the transboundary region, with emphasis on pilchard and
horse mackerel stocks within the survey area. The overall ship time of ten days available
were integrated into the yearly pelagic survey of Angola by the `R/V Dr Fridtjof Nansen' in
order to be able to continue the coverage carried out as part of the Angolan effort and in this
way utilize the ship time optimally.
The overall transboundary area was defined from Ponta Albina near Tombua in the north
(15°50' S) southwards to the Cape Frio upwelling cell (19°00' S). This definition is based
primarily on evident geographical delimiters (points) that divide the coastal area into natural
ecological zones. The northern boundary represents the northernmost extreme of the Tiger
Bank, where the continental shelf narrows in to virtually nothing. The southern boundary
represents a natural biological boundary in Namibian waters due to the presence of the
massive upwelling cell near Cape Frio. The definition of the transboundary area applied is
expected to be wide enough to cover the likely distribution area of fish migrating from
Namibia into Angolan waters and vice verse, at both warm and cold seasons.
There has been reported a decline in both abundance and mean size in all main commercial
pelagic species, particularly for sardine and horse mackerel both in Angola and Namibia.
The zone across the Angolan-Namibian border is particularly important as this area hosts
co-occurring population of carangids, i.e. Cape horse mackerel Trachurus trachurus
capensis and Cunene horse mackerel Trachurus trecae, as well as clupeids, including
sardine (Pilchard) Sardinops ocellatus, round herring (Redeye) Etrumeus whiteheadi and
anchovy Engraulis encrasicolus. There is special concern about the situation in the
transboundary area since most of these stocks are believed to be in low abundance, in
particular the sardine and the Cunene horse mackerel, while there at the same is an
intensive fisheries going on in the border area. All of these populations are, to a lesser or
greater extents, distributed across the border and there is known to be considerable
movements between seasons and years.
The main purpose of this survey is to map the distribution and estimate the abundance of the
most commercially important pelagic species across the Namibian-Angolan transboundary
area during the cold season. The study will complement the pelagic survey in Angola by
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extending the survey grid into Namibian waters, using the same sampling resolution terms of
acoustic transect lines, fish sampling (pelagic and demersal trawling) and hydrographical
mapping as in Angolan waters. A high-resolution survey grid was designed, targeting inshore
aggregations of clupeids, particularly sardine. The results are expected to provide a
snapshot of the relative distribution of the most important species across the border area in
the cold season, and will also provide important information about the abundance and
biological state of these species in the area. When assessed together with the results from
the pelagic survey in Angola, the results will provide a complete coverage of the Cunene
horse mackerel, including the proportion of the stock present in Namibian waters at the time
of the pelagic survey in Angola, if any. For sardine, the results will not cover the entire
distribution area, but will indicate total biomass in Angolan waters and in Namibian waters
south to 19°00' S.
1.1 Objectives
The main objectives of the survey were the following:
· To estimate the abundance and to map the distribution of the main commercially
important pelagic fish species, with special emphasis on the two horse mackerel
Cunene horse mackerel Trachurus trecae and Cape horse mackerel Trachurus
capensis, sardine "Pilchard" Sardinops ocellatus and other small pelagic species,
including anchovy Engraulis encrasicolus and round herring Etrumeus whiteheadi.
· To study the biological state of the main species, including length frequencies,
length-weight relationships and reproductive stages.
· To collect depth-stratified samples of zooplankton in order to determine zooplankton
vertical distribution and abundance.
· To map the meteorological and hydrographical conditions in the survey area by
means of continuous recordings of weather data (Sea-surface temperature SST,
Sea-surface salinity SSS, wind speed and-direction, CTD-casts (Temperature,
Salinity and Oxygen), stratified current measurements (Acoustic Doppler Current
Profiler ADCP).
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· On-the-job training of local participants on the main survey routines, including using
the biological database NAN-SIS, scrutinizing acoustical data (BEI) and producing
acoustical biomass estimates. A one-day training course in theoretical and applied
acoustics will be given aboard during the survey.
1.2 Participation
The following scientific staff participated in the survey:
From INIP, Angola:
Filomena VAZ-VELHO (Angolan Team Leader), Pedro TCHIPALANGA, Manuel
DOMINGOS, Miguel ANDRÉ, Pedro PANZO, Vanaquissa JONICO, José DA SILVA
and Esteves ALFONSO.
From NatMIRC, Swakopmund:
Martha UUMATI (Namibian Team Leader) and Helvi MUPUPA.
From Lüderitz Marine Research:
Jean-Paul ROUX and Benedict DUNDEE.
From IMR, Norway:
Bjørn Erik AXELSEN (Cruise Leader), Diana ZAERA, Tore MØRK and Jan Frode
WILHELMSEN.
1.3
Survey schedule
A full transceiver calibration was carried out prior to the survey in Baía dos Elephantes on 5th
August. The sampling trawls used included the smallest pelagic sample trawl (10 m vertical
opening), the mid-sized pelagic sample trawl (12 m) fitted with a remote operated codend
multisampler and the demersal sample trawl (5 m). All acoustic transducers (18, 38, 120 and
200 kHz) were operated continuously throughout the survey.
The vessel completed the pelagic survey in Angola and reached the Angolan-Namibian
border at the Cunene River (17°15' S) on the 13th of August. Extending the survey grid into
Namibian waters, the same general survey design was followed, i.e. equally spaced transect
lines (6 nautical miles (n.mi) apart) perpendicular to the coastline (isobaths). The acoustic
transects generally covered a depth range of 20-500 meters. However, some of the lines
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had to be abrupt at 30-35 m due to steeply inclining bottom near the shore in some areas.
The lines in the border area were extended offshore to about 2 000 m in order to check for
possible offshore horse mackerel aggregations. Hydrographical sections were carried out at
Pta. Albina, Baía dos Tigres and Cunene River (17°15' S) standard sections, and on every
full degree latitude line up to 19°00' S. The transboundary area southwards to 19°00' S was
completed on 18 August.
A high-resolution survey grid was designed in order to target inshore aggregations of pelagic
fish, particularly focusing on sardine, but also the other clupeids. In order to cover the
transboundary area with the highest possible density, a triangular survey design with a
spacing of 4-5 n.mi was chosen. The transfer steaming back to Tombua took about 12
hours. During this survey, only potential clupeid aggregations were sampled, but all targets
that resembled clupeids were trawled in order to check the species composition. The second
coverage was completed (19°00 S) on the 22 August. The ship then steamed to Walvis Bay
and docked 23 August.
1.4 Survey
effort
Figure 1(a and b) shows the cruise tracks with fishing and hydrographical stations in the
survey area. For this transboundary study, data from southern Angola (15°00'-17°15' S)
obtained during the previous survey (the pelagic resource survey in Angola 16 July-13
August 2005) are included. The study area for the present survey, defined as 16°00' - 19°00'
S), covers the full overlapping zone of all target species, cut off at natural geographical
delimiters (Ponta Albina near Tombua in the north and the upwelling cell south of Cape Frio).
Table 1 gives a summary of the sampling effort throughout the survey. However, note that
samples obtained during the pelagic survey in Angola are reported as well.
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Figure 1a. Course track with fishing, plankton and hydrographic stations. Depth contours at 20, 50,
100, 200 and 500 m.
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Figure 1b. Course track with fishing stations. Depth contours at 20, 50, 100, 200 and 500 m.
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Table 1. Summary of survey effort, including number of demersal (BT) and pelagic (PT) trawl hauls, CTD
casts, Multinet stations (2-5 zooplankton samples per station) and distance surveyed (log in n.mi).
Area BT
PT
Total
CTD
Multinet
Log
trawls
casts
stations
(n.mi)
Angola South
12
11
23
62
13 915
(16°00'S - 17°15' S)
Namibia North
8
11
19
39
9 1
296
(17°15'S -19°00' S)
Total 20
22
42
102
22
2
211
2 Materials and methods
During the Angolan pelagic survey the vessel has carried out continuous coverage from
Congo (Pointe Noire) through Cabinda to the Angolan-Namibian border at Cunene. During
the transboundary survey this coverage was extended southwards to Cape Frio in north of
Namibia. The overall transboundary area was defined from Ponta Albina near Tombua in the
north (15°50' S) southwards to the Cape Frio upwelling cell (19°00' S). This definition is
based primarily on evident geographical delimiters (points) that divide the coastal area into
natural ecological zones. The northern boundary represents the northernmost extreme of the
Tiger Bank, where the continental shelf narrows in to virtually nothing. The southern
boundary represents a natural biological boundary in Namibian waters due to the presence
of the massive upwelling cell near Cape Frio. The definition of the transboundary area
applied is expected to be wide enough to cover the likely distribution area of fish migrating
from Namibia into Angolan waters and vice verse, at both warm and cold seasons. The
transboundary area was covered twice, using two survey grids. The 1st grid was an
extension of the Angolan survey up to Cape Frio and the 2nd grid a high-density inshore
coverage targeting clupeids.
Survey grid 1:
The survey design of equidistant pseudo-parallel transects (6 nautical miles apart)
perpendicular to the coastline (isobaths) applied in Angola was also followed in the
extension into Namibian waters (Fig 1a). The acoustic transects generally covered a depth
range of 20-500 meters. However, some of the lines had to be abrupt at 30-35 m due to the
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steeply inclining bottom near the shoreline in some areas. The transect lines in the border
area were extended to the 2 000 m isobaths in order to check for possible offshore
aggregations of horse mackerel. This strategy ensured that the Namibian component of the
transboundary area was covered in a way that was comparable to the data already collected
in Angola. This way, distribution maps and biomass estimates could be drawn across the
border area.
Survey grid 2:
The 2nd coverage was an intensive, inshore oriented coverage covering the entire
transboundary area. The ship steamed northwards in order to start surveying from Tombua,
hence reducing the time for transfer steaming to Walvis Bay towards the end of the survey.
The main focus of this coverage was to search the study area for possible fish aggregations
that were missed by grid 1. This pertains particularly to the near depleted sardine stocks that
were not found at all neither during the Angola pelagic survey nor transboundary grid 1. The
survey grid consisted of triangular transect spaced 4-5 n.mi (Fig 1b). The lines covered from
inshore at about 20 m to the 300 m isobath. While the main focus was on acoustic searching
for sardine an other schools, trawling intensity was reduced to only include potential clupeid
schools. All observed candidates were, however, sampled using the pelagic trawls. No
biomass estimates or distribution maps were produced on the basis of the data from the
second coverage.
2.1 Acoustical sampling
The acoustic recordings were conducted using two Simrad EK 500 echosounders (Bodholt
et al. 1989) running keel mounted transducers at nominal operating frequencies of 18, 38,
120 (EK500 1) and 200 kHz (EK500 2). All the transceivers were calibrated shortly prior to
the survey, in Baía dos Elephantes on the 5th of August. Acoustic data were logged and
processed using the Sun-Unix based Bergen Echo Integrator (BEI) (Knudsen 1996) version
2000. The technical specifications, operational settings of the echosounders and calibration
parameters used during the survey are given in Annex IV.
The acoustic data were scrutinized using the post-processing module of the BEI software.
Scatterers were displayed at 38 kHz, standardized to 5 n.mi echograms with 1 000 pings
(horizontal) by 500 bins (vertical). The mean 5 n.mi area backscattering coefficients sA
(m2/n.mi2) were allocated to a predefined set of acoustic target groups by an experienced
team of operators on the basis of scrutiny of characteristic echogram features in conjunction
with information about the species- and size compositions as derived from the trawl catches.
Definitions of the acoustic target groups are given in Table 2.
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Table 2. Allocation of acoustic backscattering coefficients to acoustic target groups and their
definitions. Note that for horse mackerel, big-eye grunt and pilchard all encountered
species are listed, while only examples are listed for the remaining groups.
Species
Acoustic group
Taxonomical group
T. trecae
Horse mackerel
Trachurus sp.
T. t. capensis
Sardinella
Sardinella sp.
S. aurita
S. maderensis
Pilchard Sardinops Sardinops ocellatus
Big-eye grunt
Brachydeuterus auritus
Pelagic species 1
Clupeiformes1
Ilisha africana
Engraulis encrasicolus
Etrumeus whiteheadi
Pelagic species 2
Carangidae2
Selene dorsalis
Chloroscombrus chrysurus
Decapterus rhonchus
Seriola carpenteri
Scombridae
Auxis thazard
Sarda sarda
Scomber japonicus
Sphyraenidae
Sphyraena
guachancho
Trichiurus lepturus
Others
Lepidopus caudatus
Other demersal species
Sparidae3
Dentex angolensis
D. macrophthalmus
D. congoensis
D. canariensis
D. barnardi
Pagellus bellottii
Sparus caeruleostictus
S. pagrus africanus
Other
taxii
Saurida brasiliensis
Arioma bondi
Pomadasys incisus
Galeoides decadactylus
Merluccius spp.
Mesopelagic species
Myctophidae3
Diaphus dumerili
Other mesopelagic fish
Trachinocephalus myops
Plankton Copepoda Calanus sp.
Euphausiacea
Meganyctiphanes sp.
Chaetognatha
Other
plankton
1: other than Sardinops sp.; 2: other than Trachurus sp.; 3: main species group.
Estimation of biomass and CV
The following target strength (TS) to length relationship was used to convert mean area
backscattering coefficient sA (m2/n.mi2) at 38 kHz to number of fish:
TS = 20 log L 72 (dB)
(1)
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or
7 2
.
10
C
-
F =
2
L
(2)
4
where CF is the conversion factor from acoustic density to fish biomass and L is the mean
total fish length. This target strength function was originally established for North Sea
herring, but has later been attributed to clupeids in general (Foote et al. 1986, Foote 1987).
No specific target strength relations presently are available for the species at hand, and
equation (2) has therefore been applied consequently for all targeted species in this time
series, following the established practice in Namibia. All estimates should consequently be
considered as relative indices of abundance. The biomass was calculated by multiplying the
number of fish by the expected length at weight, as estimated by regression of the log-length
(total) against total weight.
The boundaries of encountered fish aggregations (post strata) were determined by means of
contouring within the inner and outer zero-value limits of the transect lines. The strata
contours were digitised using a CalBoard III digitising board / Atlas Draw v. 2.03 PC based
software. Distribution plots and aerial calculations on the strata were carried out using IDL
5.6 for MS Windows. Sub-stratification was used to isolate areas of similar densities, using
the following pre-defined, standard categories: 1: sA = 0-300; 2: sA = 300-1 000; 3: sA =
1000-3 000; 4: sA > 3 000. Mean 5-n.mi integrator values (sA) computed along the transect
lines were re-averaged for each stratum. The overall length frequency distributions within
strata were estimated by weighting the sample-distributions with the nearest valid 5 n.mi
integrator value, or the average of two adjacent values. The total number of fish in each
length group was estimated as:
< s > t u
A
i , j
i
7 2
.
10 t u < s > A
=
A
i, j
i
A
s
i
s
u
=
(3)
i
4 u (L +
2
)
5
.
0
C
i
i
i
Fi
i
where:
i
=
estimated number of fish in length group i
<sA> =
mean recorded area backscattering coefficient (m2/n.mi2)
ti,j
=
proportion of species j sampled in length group i
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ui
=
proportion of fish sampled in length group i
As
=
horizontal area of stratum s
CFi
=
conversion factor for length group i
Li
=
length group i (nearest full cm below total length)
Li+0.5 =
mean length in Li.
2.2
Trawl sampling procedures
A brief description and illustrations of the sampling trawls are provided in Annex IV. All trawl
catches were sampled for species composition by weights and numbers. Records of catch
rates are given in Annex II. Other species (mostly of commercial value) were collected and
identified to species level and length measurements were taken Annex III.
Biological sampling
Samples of the main target species Trachurus capensis, Trachurus trecae and Sardinops
ocellatus were collected and measured for length and weight. Total length and body weight
were determined to the nearest 1 cm and 1 g below, respectively. Sex and reproductive
stages were determined by means of macroscopic examination, scoring each fish according
to the five-point classification scale first proposed by Holden and Raitt (1974) (Angolan
species) and the seven-point classification according to Tom Hecht (Namibian species). For
the condition factor, which is the index of the length to weight proportion giving an idea on
the body condition of the fish, the length-weight relationship of target species was
determined from the regression analysis of length and weight for all stations sampled.
CF = observed weight /expected weight*100
Expected weight = a*Lb,
Zooplankton sampling
The zooplankton communities were sampled along the hydrographical sections at fixed,
predefined depths of 200, 100 and 50 m, following the sampling routine used during the prior
Angola survey. The depth ranges sampled were 0-25 m, 25-50 m, 50-75 m, 75-100 m, and
100-200 m. The sampling was conducted by means of Hydrobios Multinet, enabling up to
five depth-specific samples in one deployment. Each net (405 µm) was fitted with a
flowmeter for estimation of sample volume. A Scanmar depth sensor gave real-time
information of the depth. Nets were opened and closed remotely from the bridge of the
vessel.
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2.3
Meteorological and hydrographical sampling
Wind direction and speed, air temperature, global radiation and sea surface temperature (5
m depth) were recorded using the Aanderaa weather station. Values averaged over 10 min
intervals were logged continuously. The weather station data were logged continuously
throughout the survey. The results presented in this report are based on a standard output
from the logging system, i.e. one nautical mile averages along the ship's track.
A Seabird 911+ CTD probe was used to obtain vertical profiles of the temperature, salinity
and oxygen. Real time logging was carried out using the PC based Seabird Seasave
software. CTD casts were conducted along the cruise track in transects at CTD lines with 60
NM distance and on every 2nd transect at 200 and 50 m depth. The casts were stopped a
few meters above the bottom.
A new SBE 21 Seacat Thermosalinograph was installed during the survey of the eastern
Gulf of Guinea in 2004. Initial temperature comparisons between the CTD at 5 m and the
thermosalinograph showed temperatures 0.25 0.3°C warmer for the thermosalinograph
because of heating in the pipes, but this has been corrected by addition of another
temperature sensor mounted on the water inlet.
The ship-born Acoustic Doppler Current Profiler (ADCP) was running continuously during the
survey. The ADCP has significant interference on the 120 and 200 kHz echosounder data,
and this was tried counteracted by changing the ping synchronisation routine (trig pulse from
EK500 I), but this cannot be done without installing an external trigger unit, which will be
done at a later stage.
3 Results
Coverage 1
In this coverage T. trecae was found only in the Angolan waters (Fig. 2). The distribution was
patchy and in low densities (1 to SA 300 m2 \ n.mi2), on the inshore. Densities in the range of
300-1000 were found in the Namibe area and inside Baia dos Tigres. The biomass of T.
trecae was estimated to 44 000 tonnes, all of which was located in Angola. From this figure,
80 % of was comprised of individuals smaller than 25 cm .
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Cape horse mackerel were found continuously from south of Pta. Albina in Angola to south
of Cape Frio in Namibia (Fig. 3). Highest concentrations (SA >10 000 m2 n.mi-2) were
recorded outside of Baia dos Tigres on the inshore and at about 100 m bottom depth. The
concentration appeared to decrease southwards with two areas with intermediate densities
north and south of the 18° S line. The total biomass estimate of Cape horse mackerel was
estimated to be 393 000 tonnes, 253 000 tonnes of which were recorded in Angola and
140 000 in Namibia. From the total biomass 80 % consisted of fish less than 15 cm total
length.
The total length of Cape horse mackerel in the transboundary area ranged from 5 to 22 cm.
The length frequency distributions of the sampled fish are shown in Fig. 4. The length
frequency distribution of T. trecae in Angola (Fig. 4a) shows two well-defined cohorts with
peaks at 9 and 21 cm in total length. The length distributions of T. capensis in the
transboundary area showed, however, a mono-modal distribution with a peak around 15 cm
total length in Angola (Fig. 4b), and a less clear pattern with peaks around 10, 17 and 22 cm
in Namibia (Fig. 4c). Length-weight relationships are given in Annex III.
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Figure 2. Distribution of T.trecae in the Angola-Namibian transboundary area. Depth contours at 20,
50, 100, 200 and 500 m.
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Figure 3. Distribution of T.capensis in the Angola-Namibian transboundary area. Depth contours at
20, 50, 100, 200 and 500 m.
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a)
250
200
150
100
N (millions)
50
0
5
10
15
20
25
30
35
40
45
50
Length group (cm)
1,00
0,80
0,60
0,40
0,20
Relative cumulative biomass
0,00
5
10
15
20
25
30
35
40
Length group (cm)
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BCLME Project:LMR/NANSEN/02/05
b)
2 500
2 000
1 500
1 000
N (millions)
500
0
5
10
15
20
25
30
35
40
45
50
Length group (cm)
1,00
0,80
0,60
0,40
0,20
Relative cumulative biomass
0,00
5
10
15
20
25
30
Length group (cm)
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c)
400
300
200
N (millions)
100
0
5
10
15
20
25
30
35
40
45
50
Length group (cm)
Figure 4. Length frequencies of T. trecae sampled in Angola (a) and T. capensis sampled in Angola
(b) and Namibia (c).
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Coverage 2
Also during the second coverage, the two horse mackerel dominated the biomass of pelagic
fish in the transboundary area, as expected showing a similar distribution pattern to the first
coverage. Cunene horse mackerel was, however, found in small quantities on four trawl
stations around Cape Frio. The trawl catches prove that Cunene horse mackerel were
present in this area, while the trawl catch rates were, however, too low (0,08 to 31.20
kg/hour, Annex II) to substantiate any kind of biomass estimation.
Sardine was found in very low densities inshore in some of the trawl samples obtain during
this coverage. In the northern area scattered individuals were found in Baia dos Tigres
(catch rate of 0,67 kg/hr) and near the Cunene River (catch rate 0,46 kg/hr). In the southern
area sardine was recorded in two of the stations at about 18°S (catch rates of 2,3 and 0,17
kg/hr, respectively). Length-weight relationship of sampled sardine is given in Annex III.
Scattered individuals of anchovy and round herring were also found in some of the trawl
samples.
4 Oceanographic Conditions
Sections off Namibe (Fig. 5a). This section exhibits highest surface temperatures and
salinities with evident tropical water mass stratification indicated by isolines. The inshore
surface elevation of isolines over a steep and narrow shelf region points to some weak
upwelling process in shallow depths (up to 100m) close to the coast.
1346
1353
1346
1353
1346
1353
100
200
t
h (m)
Dep 300
400
O ml/l
T°C
S
2
500
Figure 5a. Vertical sections of temperature, salinity and oxygen off Namibe
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Pta. Albina (Fig. 5b) is separated from Namibe by approximately one degree of latitude.
Though both sections exhibit a high level of stratification through the water mass at depth,
there is a sharp decrease in both surface temperature and salinities from Namibe (T =18°C,
S = 35.9 psu) to Pta. Albina (T =15°C, S = 35.5 psu). This most likely marks the transition in
stratification dynamics from tropical to subtropical water masses.
13581362
1366
1370
13581362
1366
1370
13581362
1366
1370
100
200
t
h (m)
Dep 300
35.0
400
8
O ml/l
T°C
S
2
500
Figure 5b. Vertical sections of temperature, salinity and oxygen off Pta. Albina
Section off Baia dos Tigres (Fig. 5c): Relatively quiescent conditions prevailed near Baia
dos Tigres, and the parameters in this area showed similar water mass stratification at depth
as found off Pta. Albina. There were indications of very weak coastal upwelling close
inshore, as evidenced by elevated isolines (T, S, 02) at depths above 100m.
24
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1375
1386
1375
1386
1375
1386
100
35.3
200
12
h (m)
35.0
0.5
Dept 300
10
0.5
400
8
T°C
S
O ml/l
500
34.7
2
Figure 5c. Vertical sections of temperature, salinity and oxygen off Baía dos Tigres.
Section off Cunene River (Fig. 5d): Off the shelf edge the elevated isolines in the
temperature; salinity and oxygen profiles indicate the presence of an open ocean upwelling
process. The strong shoreward tilt of the isolines points towards the existence of an equator
ward undercurrent. There was no detectable impact from the river outflow on the properties
of the measured hydrographical parameters near the river mouth. This may be due to the
seasonal reduction in the river outflow. A similar oxygen minimum of 0.5 ml/l is found at
depths below 250 m off the shelf in regions off Pta. Albina, Baia dos Tigres and Cunene
River.
1407
1403 13991395
1407
1403 13991395
1407
1403 13991395
100
200
h (m)
Dept 300
400
T°C
S
O ml/l
2
500
Figure 5d. Vertical sections of temperature, salinity and oxygen off Cunene River.
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Section off Cape Frio (Fig. 5e): All the isolines clearly demonstrate a typical coastal
upwelling regime off Cape Frio, with the uplift of isolines near the coast indicating the
intrusion of cooler, less saline and low oxygen water from the subsurface onto the shelf.
1416
1419
1422 1425
1416
1419
1422 1425
1416
1419
1422 1425
100
200
(m)
epth
D 300
400
T°C
S
O ml/l
2
500
Figure 5e. Vertical sections of temperature, salinity and oxygen off Cape Frio.
Section off 19°S (Fig. 5f): The hydrographical conditions here are similar to those at Cape
Frio, also indicating coastal upwelling. There was a decrease observed in sea temperature
of 1°C and in the salinity of 0.2psu,from Cape Frio to 19°S, demonstrating typical
progression into the Benguela proper.
1447
1442
1437
1447
1442
1437
1447
1442
1437
100
)
m 200
t
h (
Dep 300
400
T°C
S
O ml/l
500
2
Figure 5f. Vertical sections of temperature, salinity and oxygen off 19ºS
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BCLME Project:LMR/NANSEN/02/05
Fig. 6 shows the sea surface temperature (SST ºC) (a) and sea surface salinity (SSS) (b)
recorded at 5 m depth in the transboundary area recorded using the thermosalinograph.
-15
-1
-15
-1
Namibe
Namibe
Tombwa
Tombwa
-16
-1
-16
-1
Baia dos Tigres
Baia dos Tigres
-17
-1
-17
-1
Cunene River
Cunene River
-18
-1
Cape Frio
-18
-1
Cape Frio
-19
-1
-19
-1
11
12
12
13
11
12
12
13
a
b
Figure 6. Sea surface temperature (SST ºC) (a) and sea surface salinity (SSS) (b) recorded in the
transboundary area using the thermosalinograph.
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5 Conclusion and recommendations
The results clearly show the transboundary nature of the fish resources studied. The results
also strongly support the recent reports of alarmingly low abundance levels of Cunene horse
mackerel and sardine.
The main conclusions from the survey can be summarized as:
1)
Cunene horse mackerel was found as far south as Cape Frio (19º00' S), but the
densities found south of the Angolan-Namibian border were too low to substantiate
any kind of biomass estimation. The biomass of Cunene horse mackerel in Angola
was 44 000 tons.
2)
Cape horse mackerel were found in significant amounts throughout the transboundary
area. The biomass was 253 000 tons (64 %) in Angolan waters and 140 000 in
Namibian waters (36 %), i.e. 393 000 tons in total.
3)
Scattered individuals of sardine (pilchard) were found in some of the samples on both
sides of the border during the high-density search grid for clupeids, but no
aggregations of sardine were recorded, neither acoustically nor with the sampling gear
(pelagic sample trawls). Any sizeable aggregation in this area would almost certainly
have been discovered during such an intensive surveying exercise and it is therefore
concluded that no sizeable aggregations of sardine were present in Angola or the
transboundary area at the time of the survey.
4)
Other clupeid species (round herring and anchovy) were only found in scattered, low-
density aggregations insufficient to produce any estimates of abundance.
5)
All target species found were small in size. Both horse mackerel species were less
than 25 cm, and the little that was found of various clupeids were generally of small
size groups.
The main recommendations are:
1)
The survey should be repeated at the same time of the year in order to establish
whether the observed pattern is persistent over time and to monitor development
trends in the transboundary area over time, if any.
2)
The investigation should also be conducted in the warm season. The distribution
pattern of all species under investigation here will likely be quite different in the
alternate season. Horse mackerel distributions over the transboundary area generally
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follow the position of the Angolan-Benguelan front (ABF), i.e. both species have more
southern distribution in the warm season. This will, in turn lead to expectations of more
Cunene horse mackerel in Namibian waters and less Cape horse mackerel in Angolan
waters during summer.
3)
The two countries involved should consider cooperating on continuing to monitor the
transboundary area and to coordinate management of the fish resources there; all
stocks under study here are to some extent transboundary and most stocks are in low
abundance. Only fish smaller than 25 cm were found throughout the transboundary
area and Cape horse mackerel were predominantly less than 15 cm.
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6 References
BODHOLT, H., NES, H. and H. SOLLI 1989 A new echo-sounder system. Progress in
Fisheries Acoustics. Lowestoft, Proc. I. O. A., St. Alban, UK 11(3): 123-130.
FOOTE, K. G. 1987 Fish target strengths for use in echo integrator surveys. J. Acoust.
Soc. Am. 82(3): 981-987.
FOOTE, K. G., AGLEN, A. and O. NAKKEN 1986 Measurements of fish target strength
with a split-beam echosounder. J. Acoust. Soc. Am. 80(2): 612-621.
HOLDEN, M.J. and D.F.S. RAITT (Eds) 1974 Manual of fisheries science. Part 2-
Methods of resource investigation and their application. FAO Fish. Tech. Pap.
115(1). 214p.
KNUDSEN, H. P. 1996 The Bergen Echo Integrator.
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Annex I Records of fishing stations
PROJECT STATION:3859
PROJECT STATION:3855
DATE:10/ 8/05 GEAR TYPE: BT No:14 POSITION:Lat S 1644
DATE: 9/ 8/05 GEAR TYPE: BT No:14 POSITION:Lat S 1604
start stop duration Long E 1147
start stop duration Long E 1147
TIME :14:21:49 14:33:07 11 (min) Purpose code: 1
TIME :13:11:20 13:21:14 10 (min) Purpose code: 1
LOG :4067.93 4068.55 0.60 Area code : 1
LOG :3920.48 3921.00 0.51 Area code : 1
FDEPTH: 15 16 GearCond.code:
FDEPTH: 26 25 GearCond.code:
BDEPTH: 15 16 Validity code:
BDEPTH: 26 25 Validity code:
Towing dir: 322ø Wire out: 100 m Speed: 30 kn*10
Towing dir: 2ø Wire out: 140 m Speed: 30 kn*10
Sorted: 148 Kg Total catch: 888.24 CATCH/HOUR: 4844.95
Sorted: 238 Kg Total catch: 2975.97 CATCH/HOUR: 17855.82
SPECIES CATCH/HOUR % OF TOT. C SAMP
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
weight numbers
MISCELLANEOUS 3471.05 71.64
Trachurus trecae 9954.00 211950 55.75 8196
Trachurus trecae, juvenile 968.73 16331 19.99 8204
JELLYFISH 7524.00 118200 42.14
Dicologoglossa cuneata 110.62 4615 2.28
Atractoscion aequidens 203.22 1428 1.14
Arius parkii 79.85 164 1.65
Dicologoglossa cuneata 116.22 5730 0.65
Callorhinchus capensis 76.58 33 1.58
Rhinobatos albomaculatus 26.22 78 0.15
Trichiurus lepturus 69.05 2520 1.43
Trichiurus lepturus 14.22 528 0.08
Atractoscion aequidens 49.09 753 1.01
Umbrina canariensis 9.00 300 0.05
Sepia orbignyana 17.67 229 0.36
Sardinops ocellatus 6.72 150 0.04
Umbrina canariensis 2.29 164 0.05
Raja miraletus 2.22 78 0.01
__________ ________
__________ ________
Total 4844.93 99.99
Total 17855.82 100.01
PROJECT STATION:3860
DATE:10/ 8/05 GEAR TYPE: PT No: 7 POSITION:Lat S 1637
start stop duration Long E 1145
TIME :17:52:55 18:12:41 20 (min) Purpose code: 1
LOG :4086.28 4087.46 1.17 Area code : 1
FDEPTH: 10 10 GearCond.code:
PROJECT STATION:3856
BDEPTH: 24 25 Validity code:
DATE: 9/ 8/05 GEAR TYPE: 0T No:14 POSITION:Lat S 1614
Towing dir: 357ø Wire out: 140 m Speed: 34 kn*10
start stop duration Long E 1140
TIME :22:34:26 22:41:44 7 (min) Purpose code: 1
Sorted: Kg Total catch: 25.36 CATCH/HOUR: 76.08
LOG :3964.82 3965.17 0.34 Area code : 1
FDEPTH: 60 60 GearCond.code:
BDEPTH: 60 60 Validity code:
SPECIES CATCH/HOUR % OF TOT. C SAMP
Towing dir: 355ø Wire out: 200 m Speed: 30 kn*10
weight numbers
J E L L Y F I S H 71.10 723 93.45
Sorted: 65 Kg Total catch: 1846.53 CATCH/HOUR: 15827.40
Trachurus capensis, juvenile 2.01 258 2.64 8207
Engraulis encrasicolus 1.83 219 2.41 8205
Trachurus trecae, juvenile 1.14 168 1.50 8206
SPECIES CATCH/HOUR % OF TOT. C SAMP
__________ ________
weight numbers
Total 76.08 100.00
Trachurus capensis, juvenile 15365.57 850114 97.08 8197
Dentex macrophthalmus Juv. 346.89 29803 2.19 8198
Sepia orbignyana 92.83 1714 0.59
PROJECT STATION:3861
Serranus accraensis 7.37 489 0.05
DATE:27/ 7/03 GEAR TYPE: PT No: 7 POSITION:Lat S 818
Trigla lyra 7.37 489 0.05
start stop duration Long E 1318
Dicologoglossa cuneata 7.37 249 0.05
TIME :07:05:14 07:16:30 11 (min) Purpose code: 1
__________ ________
LOG :4910.08 4910.52 0.14 Area code : 1
Total 15827.40 100.01
FDEPTH: 0 0 GearCond.code:
BDEPTH: 24 24 Validity code: 1
Towing dir: 155ø Wire out: 50 m Speed: 20 kn*10
Sorted: 36 Kg Total catch: 356.50 CATCH/HOUR: 1944.55
PROJECT STATION:3857
SPECIES CATCH/HOUR % OF TOT. C SAMP
DATE:10/ 8/05 GEAR TYPE: BT No:14 POSITION:Lat S 1619
weight numbers
start stop duration Long E 1139
Trachurus capensis, juvenile 1577.45 248236 81.12 8208
TIME :01:53:56 02:03:40 10 (min) Purpose code: 1
JELLYFISH 208.36 3327 10.72
LOG :3986.45 3986.91 0.46 Area code : 1
Etrumeus whiteheadi 158.73 9000 8.16 8209
FDEPTH: 73 70 GearCond.code:
__________ ________
BDEPTH: 73 70 Validity code:
Total 1944.54 100.00
Towing dir: 90ø Wire out: 245 m Speed: 30 kn*10
Sorted: 206 Kg Total catch: 4123.00 CATCH/HOUR: 24738.00
PROJECT STATION:3862
DATE:11/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1643
start stop duration Long E 1139
SPECIES CATCH/HOUR % OF TOT. C SAMP
TIME :08:08:08 08:15:36 7 (min) Purpose code: 1
weight numbers
LOG :4170.75 4171.21 0.45 Area code : 1
Trachurus capensis, juvenile 23832.00 1839972 96.34 8199
FDEPTH: 30 30 GearCond.code:
Dentex macrophthalmus Juv. 273.60 28548 1.11 8200
BDEPTH: 60 62 Validity code:
Dicologoglossa cuneata 202.80 12360 0.82
Towing dir: 340ø Wire out: 130 m Speed: 34 kn*10
Mustelus mustelus 162.00 240 0.65
Merluccius polli, juveniles 136.80 840 0.55
Sorted: 65 Kg Total catch: 719.73 CATCH/HOUR: 6169.11
Sepia orbignyana 44.40 360 0.18
Atractoscion aequidens 34.80 240 0.14
Diaphus dumerili 21.60 7680 0.09
SPECIES CATCH/HOUR % OF TOT. C SAMP
Trachurus trecae 18.00 360 0.07
weight numbers
Chelidonichthys capensis 10.80 240 0.04
Trachurus capensis, juvenile 5721.26 667449 92.74 8210
Serranus accraensis 1.20 120
Etrumeus whiteheadi 318.69 11786 5.17 8211
__________ ________
JELLYFISH 129.17 2.09
Total 24738.00 99.99
__________ ________
Total 6169.12 100.00
PROJECT STATION:3863
DATE:17/ 9/10 GEAR TYPE: BT No:15 POSITION:Lat S 1643
start stop duration Long E 1121
TIME :11:12:30 11:22:32 10 (min) Purpose code: 1
PROJECT STATION:3858
LOG :4196.18 4196.68 0.50 Area code : 1
DATE:10/ 8/05 GEAR TYPE: BT No:14 POSITION:Lat S 1625
FDEPTH: 140 140 GearCond.code:
start stop duration Long E 1139
BDEPTH: 140 140 Validity code:
TIME :05:47:00 05:54:06 7 (min) Purpose code: 1
Towing dir: 360ø Wire out: 400 m Speed: 35 kn*10
LOG :4020.00 4020.33 0.32 Area code : 1
FDEPTH: 79 80 GearCond.code:
Sorted: 199 Kg Total catch: 2495.36 CATCH/HOUR: 14972.16
BDEPTH: 79 80 Validity code:
Towing dir: 270ø Wire out: 245 m Speed: 30 kn*10
SPECIES CATCH/HOUR % OF TOT. C SAMP
Sorted: 51 Kg Total catch: 253.70 CATCH/HOUR: 2174.57
weight numbers
Trachurus capensis, juvenile 14148.00 548802 94.50 8212
Dentex macrophthalmus 315.00 2250 2.10 8213
SPECIES CATCH/HOUR % OF TOT. C SAMP
Etrumeus whiteheadi 165.00 2928 1.10
weight numbers
Zeus faber 66.78 300 0.45
Trachurus capensis, juvenile 1861.89 162900 85.62 8202
Pterothrissus belloci 54.78 528 0.37
Trachurus trecae 235.71 5786 10.84 8203
Merluccius polli 43.50 150 0.29
Merluccius capensis 27.00 129 1.24
Zenopsis conchifer 43.50 300 0.29
Dentex macrophthalmus 26.14 1286 1.20 8201
Scorpaena normani 38.40 450 0.26
Monolene microstoma 11.57 514 0.53
Mustelus mustelus 34.20 6 0.23
Calappa sp. 9.00 386 0.41
Trigla lyra 19.50 150 0.13
GOBIIDAE 3.00 1629 0.14
Squalus megalops 18.00 30 0.12
Chelidonichthys capensis 0.43 86 0.02
Sepia orbignyana 16.50 78 0.11
__________ ________
Monolene microstoma 9.00 300 0.06
Total 2174.74 100.00
__________ ________
Total 14972.16 100.0
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PROJECT STATION:3864
PROJECT STATION:3869
DATE:11/ 8/05 GEAR TYPE: PT No: 7 POSITION:Lat S 1636
DATE:12/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1700
start stop duration Long E 1145
start stop duration Long E 1140
TIME :16:44:15 17:19:01 35 (min) Purpose code: 1
TIME :08:11:58 08:30:29 19 (min) Purpose code: 1
LOG :4249.17 4251.58 2.40 Area code : 1
LOG :4357.04 4357.97 0.49 Area code : 1
FDEPTH: 1 1 GearCond.code:
FDEPTH: 57 57 GearCond.code:
BDEPTH: 25 24 Validity code:
BDEPTH: 57 57 Validity code:
Towing dir: 358ø Wire out: 150 m Speed: 40 kn*10
Towing dir: 350ø Wire out: 200 m Speed: 30 kn*10
Sorted: 62 Kg Total catch: 62.59 CATCH/HOUR: 107.30
Sorted: 65 Kg Total catch: 293.67 CATCH/HOUR: 927.38
SPECIES CATCH/HOUR % OF TOT. C SAMP
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
weight numbers
J E L L Y F I S H 106.97 1565 99.69
J E L L Y F I S H 371.46 60 40.05
Trachurus capensis, juvenile 0.24 45 0.22 8214
Trachurus trecae, juvenile 250.67 7775 27.03 8223
Trachurus trecae, juvenile 0.09 9 0.08 8215
Engraulis encrasicolus 108.85 6666 11.74 8225
__________ ________
Dicologoglossa cuneata 98.05 12322 10.57
Total 107.30 99.99
Trachurus capensis, juvenile 91.52 6041 9.87 8224
Maja squinado 5.12 512 0.55
Atractoscion aequidens 1.26 16 0.14
Trichiurus lepturus 0.41 28 0.04
__________ ________
Total 927.34 99.99
PROJECT STATION:3865
DATE:11/ 8/05 GEAR TYPE: PT No: 4 POSITION:Lat S 1631
start stop duration Long E 1144
TIME :18:04:09 18:26:37 22 (min) Purpose code: 1
PROJECT STATION:3870
LOG :4254.73 4256.19 1.36 Area code : 1
DATE:12/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1701
FDEPTH: 1 1 GearCond.code:
start stop duration Long E 1120
BDEPTH: 29 52 Validity code:
TIME :11:25:36 11:34:19 9 (min) Purpose code: 1
Towing dir: 335ø Wire out: 150 m Speed: 40 kn*10
LOG :4380.46 4380.90 0.44 Area code : 1
FDEPTH: 159 158 GearCond.code:
Sorted: 36 Kg Total catch: 431.28 CATCH/HOUR: 1176.22
BDEPTH: 159 158 Validity code:
Towing dir: 360ø Wire out: 515 m Speed: 30 kn*10
SPECIES CATCH/HOUR % OF TOT. C SAMP
Sorted: 95 Kg Total catch: 1357.44 CATCH/HOUR: 9049.60
weight numbers
Trachurus trecae, juvenile 416.29 54251 35.39 8217
J E L L Y F I S H 333.16 4582 28.32
SPECIES CATCH/HOUR % OF TOT. C SAMP
Trachurus capensis, juvenile 332.51 41793 28.27 8216
weight numbers
Etrumeus whiteheadi 89.35 4876 7.60 8218
Trachurus capensis, juvenile 5931.60 207733 65.55 8226
Engraulis encrasicolus 4.91 785 0.42 8219
Dentex macrophthalmus 2074.40 14300 22.92 8227
__________ ________
Merluccius capensis 266.93 1713 2.95 8228
Total 1176.22 100.00
Scorpaena normani 241.13 2193 2.66
J E L L Y F I S H 239.27 8007 2.64
Dentex angolensis 112.47 193 1.24
Cynoglossus capensis 97.20 12300 1.07
Pterothrissus belloci 20.00 380 0.22
Zeus faber 20.00 287 0.22
Umbrina canariensis 18.07 93 0.20
PROJECT STATION:3866
Dicologoglossa cuneata 10.47 2480 0.12
DATE:11/ 8/05 GEAR TYPE: PT No: 2 POSITION:Lat S 1649
Trigla lyra 9.53 287 0.11
start stop duration Long E 1124
Bothus podas africanus 7.60 193 0.08
TIME :23:39:17 23:59:21 20 (min) Purpose code: 1
Chlorophthalmus atlanticus 0.93 193 0.01
LOG :4298.47 4299.54 1.07 Area code : 1
__________ ________
FDEPTH: 100 100 GearCond.code:
Total 9049.60 99.99
BDEPTH: 128 127 Validity code:
Towing dir: 360ø Wire out: m Speed: kn*10
Sorted: 19 Kg Total catch: 18.62 CATCH/HOUR: 55.86
PROJECT STATION:3871
DATE:12/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1707
start stop duration Long E 1119
SPECIES CATCH/HOUR % OF TOT. C SAMP
TIME :13:28:12 13:58:19 30 (min) Purpose code: 1
weight numbers
LOG :4395.29 4397.05 1.75 Area code : 1
Trachurus capensis, juvenile 29.46 1782 52.74 8220
FDEPTH: 200 200 GearCond.code:
Etrumeus whiteheadi 13.38 321 23.95 8221
BDEPTH: 441 387 Validity code:
Chelidonichthys capensis 9.84 9 17.62
Towing dir: 360ø Wire out: 600 m Speed: 40 kn*10
Trigla lyra 3.24 33 5.80
__________ ________
Sorted: 134 Kg Total catch: 133.54 CATCH/HOUR: 267.08
Total 55.92 100.11
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
J E L L Y F I S H 146.96 3010 55.02
Trachurus capensis, juvenile 120.12 2458 44.98 8229
__________ ________
PROJECT STATION:3867
Total 267.08 100.00
DATE:12/ 8/05 GEAR TYPE: PT No: 2 POSITION:Lat S 1648
start stop duration Long E 1124
TIME :00:04:59 00:24:38 20 (min) Purpose code: 1
LOG :4299.81 4300.93 1.11 Area code : 1
PROJECT STATION:3872
FDEPTH: 50 50 GearCond.code:
DATE:12/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1707
BDEPTH: 128 128 Validity code:
start stop duration Long E 1129
Towing dir: 360ø Wire out: 160 m Speed: 40 kn*10
TIME :16:06:34 16:16:13 10 (min) Purpose code: 1
LOG :4413.55 4414.08 0.54 Area code : 1
Sorted: Kg Total catch: 0.31 CATCH/HOUR: 0.93
FDEPTH: 129 127 GearCond.code:
BDEPTH: 129 127 Validity code:
Towing dir: 360ø Wire out: 325 m Speed: 30 kn*10
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Sorted: 132 Kg Total catch: 785.40 CATCH/HOUR: 4712.40
Centrolophus niger 0.90 3 96.77
Pteroscion peli 0.03 36 3.23
__________ ________
SPECIES CATCH/HOUR % OF TOT. C SAMP
Total 0.93 100.00
weight numbers
Trachurus capensis, juvenile 4005.36 176484 85.00 8230
Dentex macrophthalmus 385.92 2988 8.19 8231
Merluccius capensis 231.12 1404 4.90 8232
Synagrops microlepis 34.20 5220 0.73
PROJECT STATION:3868
Trigla lyra 21.24 108 0.45
DATE:12/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1650
Zeus faber 19.08 72 0.40
start stop duration Long E 1118
Saurida brasiliensis 15.48 540 0.33
TIME :02:09:43 02:37:03 27 (min) Purpose code: 1
__________ ________
LOG :4311.71 4313.11 1.38 Area code : 1
Total 4712.40 100.00
FDEPTH: 353 362 GearCond.code:
BDEPTH: 353 362 Validity code:
Towing dir: 360ø Wire out:1000 m Speed: 30 kn*10
PROJECT STATION:3873
Sorted: 32 Kg Total catch: 1617.50 CATCH/HOUR: 3594.44
DATE:13/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1713
start stop duration Long E 1130
TIME :23:52:20 00:22:22 30 (min) Purpose code: 1
SPECIES CATCH/HOUR % OF TOT. C SAMP
LOG :4455.03 4456.84 1.81 Area code : 1
weight numbers
FDEPTH: 100 100 GearCond.code:
Merluccius capensis 1355.56 2556 37.71 8222
BDEPTH: 140 135 Validity code:
Scorpaena normani 1184.44 164000 32.95
Towing dir: 360ø Wire out: 300 m Speed: 40 kn*10
Nematocarcinus africanus 238.89 184556 6.65
Pterothrissus belloci 234.44 1333 6.52
Sorted: Kg Total catch: 160.78 CATCH/HOUR: 321.56
Aristeus varidens 217.78 2667 6.06
Hoplostethus cadenati 125.56 5556 3.49
Gadella imberbis 102.22 1889 2.84
SPECIES CATCH/HOUR % OF TOT. C SAMP
Chlorophthalmus atlanticus 76.67 2222 2.13
weight numbers
Dentex macrophthalmus 35.56 111 0.99
J E L L Y F I S H 295.20 5496 91.80
MARME03 23.33 667 0.65
Trachurus capensis, juvenile 26.36 1582 8.20 8233
__________ ________
__________ ________
Total 3594.45 99.99
Total 321.56 100.00
32
BCLME Project:LMR/NANSEN/02/05
PROJECT STATION:3874
PROJECT STATION:3878
DATE:13/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1727
DATE:15/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1800
start stop duration Long E 1132
start stop duration Long E 1141
TIME :15:26:38 15:27:48 1 (min) Purpose code: 1
TIME :03:49:11 03:53:40 4 (min) Purpose code: 1
LOG :4568.73 4568.74 0.01 Area code : 5
LOG :4854.30 4854.58 0.28 Area code : 5
FDEPTH: 147 147 GearCond.code:
FDEPTH: 90 90 GearCond.code:
BDEPTH: 147 147 Validity code:
BDEPTH: 117 118 Validity code:
Towing dir: 360ø Wire out: m Speed: kn*10
Towing dir: 340ø Wire out: 270 m Speed: 45 kn*10
Sorted: 183 Kg Total catch: 183.88 CATCH/HOUR: 11032.80
Sorted: 97 Kg Total catch: 97.05 CATCH/HOUR: 1455.75
SPECIES CATCH/HOUR % OF TOT. C SAMP
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
weight numbers
Aequorea aequorea 7597.80 90960 68.87
Chrysaora hysoscella 1072.20 11235 73.65
Chrysaora hysoscella 2700.60 9480 24.48
Trachurus capensis, juvenile 296.40 15300 20.36 8238
Trachurus capensis, juvenile 717.60 19740 6.50 8234
Aequorea aequorea 73.80 1605 5.07
Merluccius capensis 15.00 120 0.14
Merluccius capensis 8.85 15 0.61
Dentex macrophthalmus 1.80 60 0.02
Sufflogobius bibarbatus 2.85 30 0.20
__________ ________
PARALEPIDIDAE 1.65 45 0.11
Total 11032.80 100.01
__________ ________
Total 1455.75 100.00
PROJECT STATION:3879
DATE:15/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1808
start stop duration Long E 1144
TIME :08:13:58 08:18:16 4 (min) Purpose code: 1
PROJECT STATION:3875
LOG :4877.66 4877.88 0.22 Area code : 5
DATE:13/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1727
FDEPTH: 98 99 GearCond.code:
start stop duration Long E 1109
BDEPTH: 98 99 Validity code:
TIME :18:51:37 19:36:14 45 (min) Purpose code: 1
Towing dir: 333ø Wire out: 300 m Speed: 30 kn*10
LOG :4598.22 4600.99 2.76 Area code : 5
FDEPTH: 200 100 GearCond.code:
Sorted: 66 Kg Total catch: 232.61 CATCH/HOUR: 3489.15
BDEPTH: 1058 841 Validity code:
Towing dir: 90ø Wire out: 700 m Speed: 40 kn*10
SPECIES CATCH/HOUR % OF TOT. C SAMP
Sorted: 7 Kg Total catch: 7.02 CATCH/HOUR: 9.36
weight numbers
Trachurus capensis 1644.30 81855 47.13 8239
Chrysaora hysoscella 990.15 4260 28.38
SPECIES CATCH/HOUR % OF TOT. C SAMP
Merluccius capensis 86.10 735 2.47 8240
weight numbers
Aequorea aequorea 30.40 9320 0.87
ALEPOCEPHALIDAE 3.68 392 39.32
Pterothrissus belloci 18.90 375 0.54
OPLOPHORIDAE 1.57 996 16.77
Sufflogobius bibarbatus 6.30 1845 0.18
Gonostoma elongatum 0.84 75 8.97
__________ ________
TRACHICHTHYIDAE 0.80 3 8.55
Total 2776.15 79.57
MISCELLANEOUS 0.76 8.12
MYCTOPHIDAE 0.32 120 3.42
Nemichthys scolopaceus 0.32 84 3.42
PROJECT STATION:3880
Argyropelecus affinis 0.28 101 2.99
DATE:15/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1817
Schedophilus huttoni 0.21 1 2.24
start stop duration Long E 1138
OCTOPOTEUTHIDAE 0.15 4 1.60
TIME :16:11:00 16:13:55 3 (min) Purpose code: 1
Trachurus capensis 0.12 1 1.28
LOG :4937.92 4938.08 0.16 Area code : 5
CARISTIIDAE 0.07 3 0.75
FDEPTH: 156 157 GearCond.code:
BATHYLAGIDAE 0.05 11 0.53
BDEPTH: 156 157 Validity code:
LYCOTEUTHIDAE 0.05 4 0.53
Towing dir: 350ø Wire out: 490 m Speed: 30 kn*10
Hoplostethus cadenati 0.05 1 0.53
MELANOCETIDAE 0.03 7 0.32
Sorted: 175 Kg Total catch: 350.08 CATCH/HOUR: 7001.60
OMMASTREPHIDAE 0.01 3 0.11
PARALEPIDIDAE 0.01 1 0.11
SPECIES CATCH/HOUR % OF TOT. C SAMP
Illex coindetii 0.01 5 0.11
weight numbers
Bregmaceros atlanticus 0.01 3 0.11
Aequorea aequorea 3080.00 76200 43.99
__________ ________
Chrysaora hysoscella 1732.00 8200 24.74
Total 9.34 99.78
Trachurus capensis 1526.40 31220 21.80 8241
Merluccius capensis 421.60 2160 6.02 8242
Dentex macrophthalmus 177.20 1640 2.53 8243
Synagrops microlepis 30.40 9320 0.43
Sufflogobius bibarbatus 28.00 11080 0.40
Pterothrissus belloci 5.60 280 0.08
Calappa rubroguttata 0.40 280 0.01
PROJECT STATION:3876
__________ ________
DATE:14/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1746
Total 7001.60 100.00
start stop duration Long E 1122
TIME :09:53:12 10:21:29 28 (min) Purpose code: 1
LOG :4732.37 4734.27 1.90 Area code : 5
PROJECT STATION:3881
FDEPTH: 200 225 GearCond.code:
DATE:16/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1832
BDEPTH: 309 391 Validity code:
start stop duration Long E 1201
Towing dir: 333ø Wire out: 800 m Speed: 40 kn*10
TIME :09:28:16 09:34:01 6 (min) Purpose code: 1
LOG :5050.53 5050.78 0.25 Area code : 5
Sorted: 7 Kg Total catch: 6.78 CATCH/HOUR: 14.53
FDEPTH: 44 46 GearCond.code:
BDEPTH: 44 46 Validity code:
Towing dir: 333ø Wire out: 150 m Speed: 30 kn*10
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Sorted: 60 Kg Total catch: 182.58 CATCH/HOUR: 1825.80
J E L L Y F I S H 4.65 58 32.00
Trachipterus sp. 3.75 4 25.81
MYCTOPHIDAE 2.55 1513 17.55
SPECIES CATCH/HOUR % OF TOT. C SAMP
Trachurus capensis 1.67 21 11.49 8235
weight numbers
PARALEPIDIDAE 1.03 75 7.09
Trachurus capensis, juvenile 1160.40 127830 63.56 8244
Yarrella blackfordi 0.51 58 3.51
Chrysaora hysoscella 591.60 5130 32.40
Nemichthys scolopaceus 0.36 133 2.48
Dicologoglossa cuneata 52.50 2400 2.88
__________ ________
Chelidonichthys gabonensis 18.60 30 1.02
Total 14.52 99.93
Calappa sp. 2.10 60 0.12
Pterothrissus belloci 0.60 20 0.03
__________ ________
Total 1825.80 100.01
PROJECT STATION:3877
PROJECT STATION:3882
DATE:14/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1746
DATE:16/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1845
start stop duration Long E 1133
start stop duration Long E 1131
TIME :12:37:41 12:41:50 4 (min) Purpose code: 1
TIME :13:54:51 14:05:12 10 (min) Purpose code: 1
LOG :4750.69 4750.92 0.22 Area code : 5
LOG :5089.74 5090.29 0.54 Area code : 1
FDEPTH: 165 167 GearCond.code:
FDEPTH: 257 257 GearCond.code:
BDEPTH: 165 167 Validity code:
BDEPTH: 257 257 Validity code:
Towing dir: 360ø Wire out: 510 m Speed: 30 kn*10
Towing dir: 345ø Wire out: 767 m Speed: 30 kn*10
Sorted: 57 Kg Total catch: 170.63 CATCH/HOUR: 2559.45
Sorted: 56 Kg Total catch: 588.85 CATCH/HOUR: 3533.10
SPECIES CATCH/HOUR % OF TOT. C SAMP
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
weight numbers
J E L L Y F I S H 1083.15 37305 42.32
Merluccius capensis 2502.36 8316 70.83 8245
Trachurus capensis 1083.15 27000 42.32 8236
Dentex macrophthalmus 509.04 2646 14.41 8246
Merluccius capensis 195.60 795 7.64 8237
Pterothrissus belloci 281.58 2772 7.97
Chrysaora hysoscella 94.50 225 3.69
Chlorophthalmus atlanticus 56.04 3342 1.59
Dentex macrophthalmus 61.65 585 2.41
PORTUNIDAE 40.32 2712 1.14
Synagrops microlepis 22.05 5625 0.86
Helicolenus dactylopterus 37.80 2394 1.07
Chlorophthalmus atlanticus 8.55 720 0.33
Synagrops microlepis 34.80 4476 0.98
Sufflogobius bibarbatus 7.65 540 0.30
Schedophilus pemarco 24.54 66 0.69
Pterothrissus belloci 2.25 45 0.09
Galeus polli 18.90 318 0.53
Dicologoglossa cuneata 0.90 45 0.04
Sufflogobius bibarbatus 17.64 5922 0.50
__________ ________
Lophius vomerinus 10.08 192 0.29
Total 2559.45 100.00
__________ ________
Total 3533.10 100.00
33
BCLME Project:LMR/NANSEN/02/05
PROJECT STATION:3883
DATE:16/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1845
start stop duration Long E 1132
PROJECT STATION:3888
TIME :15:39:39 16:00:51 21 (min) Purpose code: 1
DATE:19/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1653
LOG :5097.46 5098.80 1.33 Area code : 5
start stop duration Long E 1139
FDEPTH: 250 240 GearCond.code:
TIME :19:35:22 19:53:27 18 (min) Purpose code: 1
BDEPTH: 255 254 Validity code:
LOG :5779.28 5780.56 1.28 Area code : 1
Towing dir: 345ø Wire out: 737 m Speed: 40 kn*10
FDEPTH: 30 30 GearCond.code:
BDEPTH: 56 70 Validity code:
Sorted: 24 Kg Total catch: 23.85 CATCH/HOUR: 68.14
Towing dir: 260ø Wire out: 170 m Speed: 40 kn*10
Sorted: 75 Kg Total catch: 75.49 CATCH/HOUR: 251.63
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
MYCTOPHIDAE 51.11 25174 75.01
SPECIES CATCH/HOUR % OF TOT. C SAMP
Aequorea aequorea 14.29 326 20.97
weight numbers
Chrysaora hysoscella 2.31 14 3.39
Chrysaora hysoscella 138.53 670 55.05
Dentex macrophthalmus 0.43 3 0.63
Engraulis encrasicolus 82.33 19080 32.72 8252
__________ ________
Aequorea aequorea 17.13 133 6.81
Total 68.14 100.00
Trachurus capensis, juvenile 7.43 430 2.95 8253
Etrumeus whiteheadi 5.53 307 2.20 8255
Sardinops ocellatus 0.67 57 0.27 8254
__________ ________
PROJECT STATION:3884
Total 251.62 100.00
DATE:16/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1854
start stop duration Long E 1132
TIME :20:53:31 21:12:00 18 (min) Purpose code: 1
LOG :5135.67 5136.87 1.20 Area code : 5
PROJECT STATION:3889
FDEPTH: 250 30 GearCond.code:
DATE:20/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1659
BDEPTH: 271 271 Validity code:
start stop duration Long E 1139
Towing dir: 170ø Wire out: 150 m Speed: 40 kn*10
TIME :01:10:37 01:26:07 16 (min) Purpose code: 1
LOG :5830.54 5831.66 0.15 Area code : 1
Sorted: 75 Kg Total catch: 75.20 CATCH/HOUR: 250.67
FDEPTH: 15 14 GearCond.code:
BDEPTH: 60 70 Validity code:
Towing dir: 276ø Wire out: 100 m Speed: 45 kn*10
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Sorted: 37 Kg Total catch: 73.60 CATCH/HOUR: 276.00
MYCTOPHIDAE 220.80 218040 88.08
Brama brama 16.00 13 6.38
Chrysaora hysoscella 13.60 80 5.43
SPECIES CATCH/HOUR % OF TOT. C SAMP
PARALEPIDIDAE 0.27 93 0.11
weight numbers
__________ ________
Engraulis encrasicolus 207.90 18975 75.33 8257
Total 250.67 100.00
Aequorea aequorea 34.58 473 12.53
Chrysaora hysoscella 33.08 428 11.99
Trachurus capensis 0.45 98 0.16 8256
__________ ________
Total 276.01 100.01
PROJECT STATION:3885
DATE:17/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1903
start stop duration Long E 1136
PROJECT STATION:3890
TIME :11:36:53 12:06:21 29 (min) Purpose code: 1
DATE:20/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1712
start stop duration Long E 1132
LOG :5236.31 5238.11 1.79 Area code : 5
TIME :09:05:31 09:22:26 17 (min) Purpose code: 1
FDEPTH: 150 140 GearCond.code:
LOG :5909.11 5910.18 1.07 Area code : 1
BDEPTH: 282 286 Validity code:
FDEPTH: 50 50 GearCond.code:
Towing dir: 64ø Wire out: 450 m Speed: 35 kn*10
BDEPTH: 120 129 Validity code:
Towing dir: 290ø Wire out: 200 m Speed: 40 kn*10
Sorted: 35 Kg Total catch: 69.32 CATCH/HOUR: 143.42
Sorted: 48 Kg Total catch: 47.50 CATCH/HOUR: 167.65
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
SPECIES CATCH/HOUR % OF TOT. C SAMP
Aequorea aequorea 106.10 3103 73.98
weight numbers
MYCTOPHIDAE 31.12 24894 21.70
Aequorea aequorea 109.91 198 65.56
Chrysaora hysoscella 6.21 21 4.33
Etrumeus whiteheadi 56.89 646 33.93 8259
__________ ________
Sardinops ocellatus 0.46 11 0.27 8260
Total 143.43 100.01
Trachurus capensis, juvenile 0.39 49 0.23 8258
__________ ________
Total 167.65 99.99
PROJECT STATION:3886
DATE:18/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1557
start stop duration Long E 1145
PROJECT STATION:3891
TIME :12:38:08 12:43:50 6 (min) Purpose code: 1
DATE:20/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1731
LOG :5478.45 5478.77 0.30 Area code : 1
start stop duration Long E 1142
FDEPTH: 21 22 GearCond.code:
TIME :21:00:25 21:19:32 19 (min) Purpose code: 1
BDEPTH: 21 22 Validity code:
LOG :6026.07 6027.42 1.34 Area code : 1
Towing dir: 285ø Wire out: 100 m Speed: 32 kn*10
FDEPTH: 30 30 GearCond.code:
BDEPTH: 59 82 Validity code:
Sorted: 32 Kg Total catch: 347.27 CATCH/HOUR: 3472.70
Towing dir: 260ø Wire out: 160 m Speed: 40 kn*10
Sorted: 33 Kg Total catch: 33.19 CATCH/HOUR: 104.81
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Trachurus trecae, juvenile 3282.40 203170 94.52 8247
SPECIES CATCH/HOUR % OF TOT. C SAMP
Arius parkii 83.60 110 2.41
weight numbers
J E L L Y F I S H 72.25 68.93
Mustelus mustelus 53.90 110 1.55
Etrumeus whiteheadi 14.43 714 13.77 8263
Umbrina canariensis 15.40 440 0.44
Trachurus capensis, juvenile 13.45 1427 12.83 8261
Dentex barnardi 9.90 220 0.29
Trachurus trecae, juvenile 4.67 1197 4.46 8262
Pomadasys incisus 8.80 330 0.25
__________ ________
Trichiurus lepturus 7.70 330 0.22
Total 104.80 99.99
Galeus polli 6.60 110 0.19
Dicologoglossa cuneata 4.40 110 0.13
__________ ________
Total 3472.70 100.00
PROJECT STATION:3892
DATE:21/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1743
start stop duration Long E 1144
TIME :03:21:03 03:21:20 9 (min) Purpose code: 1
LOG :6089.23 6089.83 0.61 Area code : 1
PROJECT STATION:3887
FDEPTH: 15 15 GearCond.code:
DATE:19/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1642
BDEPTH: 44 55 Validity code:
start stop duration Long E 1140
Towing dir: 274ø Wire out: 100 m Speed: 45 kn*10
TIME :09:26:02 09:46:50 21 (min) Purpose code: 1
LOG :5685.13 5686.18 1.05 Area code : 1
Sorted: 38 Kg Total catch: 115.11 CATCH/HOUR: 767.40
FDEPTH: 37 40 GearCond.code:
BDEPTH: 37 40 Validity code:
Towing dir: 349ø Wire out: 140 m Speed: 30 kn*10
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Sorted: 27 Kg Total catch: 162.66 CATCH/HOUR: 464.74
Etrumeus whiteheadi 531.60 42000 69.27 8266
Chrysaora hysoscella 189.60 2640 24.71
Sardinops ocellatus 33.20 2260 4.33 8264
SPECIES CATCH/HOUR % OF TOT. C SAMP
Trachurus capensis, juvenile 13.00 2680 1.69 8265
weight numbers
__________ ________
Trachurus trecae 242.06 7646 52.09 8248
Total 767.40 100.00
JELLYFISH 180.00 2451 38.73
Umbrina canariensis 9.43 343 2.03
Rhinobatos rhinobatos 8.40 17 1.81
Sepia officinalis hierredda 7.54 17 1.62
Engraulis encrasicolus 5.31 411 1.14 8251
Raja miraletus 4.63 17 1.00
Loligo vulgaris 4.29 703 0.92
Trachurus capensis, juvenile 2.06 240 0.44 8250
Sardinops ocellatus 1.03 11 0.22 8249
__________ ________
Total 464.75 100.00
34
BCLME Project:LMR/NANSEN/02/05
PROJECT STATION:3893
DATE:21/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1749
start stop duration Long E 1145
TIME :06:41:22 06:41:36 6 (min) Purpose code: 1
LOG :6124.46 6124.95 0.48 Area code : 5
FDEPTH: 20 20 GearCond.code:
BDEPTH: 41 39 Validity code:
Towing dir: 160ø Wire out: 120 m Speed: 40 kn*10
Sorted: 77 Kg Total catch: 459.59 CATCH/HOUR: 4595.90
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Chrysaora hysoscella 2635.20 20340 57.34
Etrumeus whiteheadi 882.00 60570 19.19 8273
Trachurus capensis, juvenile 746.40 128220 16.24 8275
Engraulis encrasicolus 298.80 15840 6.50 8274
Trachurus trecae, juvenile 31.20 7620 0.68 8271
Sardinops ocellatus 2.30 80 0.05 8272
__________ ________
Total 4595.90 100.00
PROJECT STATION:3894
DATE:21/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1757
start stop duration Long E 1145
TIME :11:29:29 11:50:51 21 (min) Purpose code: 1
LOG :6157.05 6158.23 1.17 Area code : 5
FDEPTH: 55 56 GearCond.code:
BDEPTH: 55 56 Validity code:
Towing dir: 355ø Wire out: 140 m Speed: 40 kn*10
Sorted: 33 Kg Total catch: 65.42 CATCH/HOUR: 186.91
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Trachurus capensis, juvenile 79.66 15320 42.62 8276
Chrysaora hysoscella 60.46 994 32.35
Aequorea aequorea 37.31 920 19.96
Etrumeus whiteheadi 8.57 829 4.59 8278
Trachurus trecae, juvenile 0.74 194 0.40 8277
Sardinops ocellatus 0.17 3 0.09 8279
__________ ________
Total 186.91 100.01
PROJECT STATION:3895
DATE:21/ 8/05 GEAR TYPE: PT No: 1 POSITION:Lat S 1808
start stop duration Long E 1148
TIME :17:50:52 18:07:11 16 (min) Purpose code: 1
LOG :6215.43 6216.49 1.04 Area code : 5
FDEPTH: 20 20 GearCond.code:
BDEPTH: 52 51 Validity code:
Towing dir: 165ø Wire out: 120 m Speed: 40 kn*10
Sorted: 33 Kg Total catch: 68.65 CATCH/HOUR: 257.44
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
J E L L Y F I S H 161.25 3540 62.64
Trachurus capensis, juvenile 69.30 11014 26.92 8267
Etrumeus whiteheadi 16.88 1778 6.56 8268
Chelidonichthys capensis 7.73 8 3.00
Callorhinchus capensis 1.46 4 0.57
Engraulis encrasicolus 0.75 75 0.29 8269
Trachurus trecae, juvenile 0.08 11 0.03 8270
__________ ________
Total 257.45 100.01
PROJECT STATION:3896
DATE:22/ 8/05 GEAR TYPE: BT No:15 POSITION:Lat S 1850
start stop duration Long E 1217
TIME :08:46:02 08:57:26 11 (min) Purpose code: 1
LOG :6361.30 6361.86 0.55 Area code : 5
FDEPTH: 62 67 GearCond.code:
BDEPTH: 62 67 Validity code:
Towing dir: 256ø Wire out: 200 m Speed: 30 kn*10
Sorted: 56 Kg Total catch: 223.56 CATCH/HOUR: 1219.42
SPECIES CATCH/HOUR % OF TOT. C SAMP
weight numbers
Trachurus capensis 740.51 27284 60.73 8280
J E L L Y F I S H 228.65 2400 18.75
Chelidonichthys capensis 108.87 240 8.93
Myliobatis aquila 107.35 22 8.80
Monolene microstoma 16.36 458 1.34
Merluccius capensis 13.09 153 1.07
Squalus megalops 3.49 22 0.29
CONGRIDAE 1.09 305 0.09
__________ ________
Total 1219.41 100.00
35
BCLME Project:LMR/NANSEN/02/05
Annex II Catch rates
Station Depth
(m) T.trecae T.capensis
Sardinops Anchovy Round
herring Others
Total
3855
26
9 954,00
6,72
7 895,10
7 901,82
3856
60
15 365,57
461,83
15 827,40
3857
72
18,00
23 832,00
888,00
24 720,00
3858
80
235,71
1 861,89
77,14
1 939,03
3859
16
968,73
3 876,20
3 876,20
3860 10
1,14
2,01
1,83
71,10
74,94
3861
15
1 577,45
158,73
208,36
1 944,54
3862
30
5 721,26
318,69
129,17
6 169,12
3863
140
14 148,00
165,00
659,16
14 972,16
3864 1
0,09
0,24
106,97
107,21
3865 1 416,29
332,51
4,91
89,35
333,16
759,93
3866 100
29,46
13,38 13,08
55,92
3867 50
0,93
0,93
3868 358
3 594,45
3 594,45
3869 57 250,67
91,52
108,85
476,30
676,67
3870
159
5 931,60
3 118,00
9 049,60
3871 200
120,12
146,96
267,08
3872
128
4 005,36
707,04
4 712,40
3873 100
26,36
295,20
321,56
3874
147
717,60
10 315,20
11 032,80
3875 150
0,12
9,22
9,34
3876 213
1,67
12,85
14,52
3877
166
1 083,15
1 476,30
2 559,45
3878
90
296,40
1 159,35
1 455,75
3879
99
1 644,30
1 131,85
2 776,15
3880
157
1 526,40
5 475,20
7 001,60
3881
45
1 160,40
665,40
1 825,80
3882 257
3 533,10
3 533,10
3883 245
68,14
68,14
3884 140
250,67
250,67
3885 145
143,43
143,43
3886 22 3
282,40
190,30
190,30
3887 39 242,06
2,06
1,03
5,31
214,29
222,69
3888 30
7,43
0,67
82,33
5,53
155,66
251,62
3889 15
0,45
207,90
67,66
276,01
3890 50
0,39
0,46
56,89
109,91
167,65
3891 30
4,67
13,45
14,43
72,25
100,13
3892 15
13,00
33,20
531,60
189,60
767,40
3893
20
31,20
746,00
2,30
298,80
882,00
2 635,20
4 564,30
3894 56
0,74
79,66
0,17
8,57
97,77
186,17
3895 20
0,08
69,30
0,75
16,88
170,44
257,37
3896 65
740,51
478,90
1
219,41
Mean
90,93
366,80
1 932,09
1,06
16,92
53,83
1 230,50
3 234,40
STDEV
1 604,08
4 805,41
5,20
58,26
164,15
2 211,10
5 212,53
% Catch
11,34
59,74
0,03
0,52
1,66 38,04
36
Annex III Length weight relationships, gonad maturity and Length
distribution
(a)
T.trecae
y = 0,3337x1,6443
R2 = 0,5791
60
50
40
30
Weight (g) 20
10
0
5
10
15
20
Total Length (cm)
(b)
T.capensis
y = 0,0098x2,8977
R2 = 0,9709
150
100
eight (g)
50
W
0
0
10
20
30
Total Length (cm)
(c)
S. ocellatus
30
y = 0,0194x2,5953
25
R2 = 0,8684
20
15
eight (g)
W 10
5
0
0
5
10
15
20
Total Length (cm)
Figure 1.-Length-Weight relationship of T. trecae (a), T. capensis (b) and S. ocellatus (c).
37
35
30
25
c
y
n
ue
20
FEMALE
e
q
15
MALE
% Fr
10
5
0
1
2
3
4
5
6
Gonad maturity stages
Figure 2.- Gonad maturity stages by sex of T. capensis.
38
(a)
400
300
200
N (millions)
100
0
5
10
15
20
25
30
35
40
45
50
Length group (cm)
(b)
1,00
0,80
0,60
0,40
Relative cumulative biomass 0,20
0,00
5
10
15
20
25
30
35
40
Length group (cm)
Figure 3.- Overall length distribution in numbers (a) ) and relative cumulative biomass (b) of
T. capensis in Namibia.
39
Annex IV Instruments and fishing gear
The Simrad EK-500, 38 kHz echo scientific sounder was used during the survey
for fish abundance estimation, in addition data from the 18 kHz, 120 kHz and the
200 kHz transducers were logged for possible future multi frequency target
estimation. The Bergen Echo Integrator system (BEI) logging the echogram raw
data from the sounder, was used to scrutinize the acoustic records, and to
allocate integrator data to fish species. All raw data were stored to tape, and a
backup of the database of scrutinized data. The details of the settings of the
38 kHz were as follows:
Transceiver-1 menu
Transducer depth
5.5 m
Absorption coeff.
10 dB/km
Pulse length medium (1ms)
Bandwidth
wide
Max power
2000 Watt
2-way beam angle
-21.0 dB
SV transducer gain
27.19 dB
TS transducer gain
27.22 dB
Angle
sensitivity
21.9
3 dB beamwidth along. 6.9°
3 dB beamwidth athw. 6.8°
Alongship
offset
-0.01°
Athwardship
offset
0.03°
Display menu
Echogram 1
Bottom range
10 m
Bottom range start
9 m
TVG
20 log R
Sv colour min
-67 dB
TS Colour minimum
-60 dB
Printer- menu
Range
0 - 50, 0 - 100, 0 - 150, 0 - 250 or
0 - 500m
TVG
20 log R
Sv colour min
-60 dB
Bottom detection menu
Minimum level
-40 dB
A calibration experiment using a standard copper sphere was performed in Baía dos
Elephantes, Angola 5th August 2005. These settings used during the survey.
Fishing gear
40
The vessel has two different sized "Åkrahamn" pelagic trawls and one "Gisund
super" bottom trawl. For all trawls, the Tyborøn, 7.8m² (1670 kg) trawl doors
were used.
Figure 1 Design of the trawl used.
41
ANNEX V Seabirds and Marine Mammals distribution and patterns of
abundance
(Contribution to the `Top Predador' BCLME Project LMR/EAF/03/02)
Participants from 28 July 2005:
Jean-Paul Roux, MFMR Lüderitz,
Trainees:
Benedictus Dundee, MFMR Lüderitz
Jose da Silva, University Agostinho Neto, Luanda
AIMS
1. Make an inventory of seabird and marine mammal species present in the survey
area
2. Estimate relative density of the different seabird species along the transect lines
3. Analyse patterns of distribution and abundance in relation to oceanographic
features and fish distribution
4. Training on bird identification at sea and seabird survey methods
5. Record additional visual information on surface oceanographic features (slicks,
water discoloration, flotsam lines) and fish (presence of pelagic sharks, surface
aggregations of pelagic fish).
METHODS
Counts of seabirds were made during daylight hours from the top-deck of the
vessel, which offers excellent viewing conditions. The viewing height above sea level,
measured in Luanda harbour, was 14.96 m at mid-deck.
When possible, standard "10-minute-counts" of the birds present around the
vessel were effected while the vessel was steaming at constant speed and heading.
During each count period, all birds detected were counted, discriminating between
birds seen actively following the vessel (within an arc of 60o aft), birds flying and birds
sitting or feeding. During the counts, scans with binoculars were effected at least
once every two minutes to detect inconspicuous species. Care was taken to count
individual birds only once particularly for species prone to follow or circle the vessel
and not to conduct 10 minute counts soon after a station or a trawl which have
attracted birds to the vessel. This method was chosen in order to record all species
42
seen including the scarce and rare species. The results of this method give a
species-specific index of abundance rather than absolute densities.
Additional "incidental observations" were made, between counts when scarce
or unusual species were observed and while the vessel was on station or during
trawling when standardized quantification of abundance was not possible. The time
and duration of each observation and count was recorded with watches synchronized
to the vessel's in order to match them with the data recorded by the electronic log
and weather station (position, speed, depth, heading, sea temperature etc.) as well
as environmental and biological parameters recorded during the survey. Additional
information on the age classes of some species was noted (albatrosses, gannets,
gulls).
Sightings of Cape fur seals were recorded following the same format. Each
cetacean sighting was recorded in a way similar to the `incidental sightings' of
uncommon bird species above. A measure of effort was obtained by recording the
periods of continuous observations (and relating them to the vessel route) to be
modified by estimated sea state and visibility.
Fish schools visible at the surface were recorded following an estimated
relative four-point scale: small (a few to 100 m2), medium (between 100 and 250 m2)
large (between 250 and 500 m2) and very large (> 500 m2). Pelagic shark sightings
were also recorded. Additional visual information as flotsam lines, slicks, water
discoloration etc. was also logged in the same format as well as photographically
documented.
RESULTS
A total of 266 "10-minute counts" were effected between 28 July and 16
August. In addition, 130 incidental observations were logged, including 12 during
Multinet sampling, 23 during CTD stations, and 18 during trawling. The summary of
the distribution of the observations is given in Fig 1.
43
-8.5
-8.5
t
.
t
.
-9
Sampling effort
-9
La
La
Sampling effort
-9.5
-9.5
-10
Incidental
Incidental
-10
10'count
-10.5
10'count
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 1. Distribution of the sampling effort (10 min counts and incidental observations on the
left and Latitude-Depth plot (log scale) on the right.
44
Species accounts
The list species and numbers identified during the survey are given in Table 1
for birds and seals.
Table 1: Seabird species and numbers of individuals identified during the 10' observation
periods and in total (including incidental sightings). The overall percentage of
occurrence (% FO) in the 10-minute count periods (N=266) and Cape fur seal
numbers are also given. *Several tens of thousands of Cape cormorant roosting and
feeding in Baia dos Tigres excluded.
Species
Bird numbers
10' count
All records 10 min counts FO %
Thalassarche melanophris
Black-browed albatross
4
2
0.75
Thalassarche chlororhynchos Yellow-nosed albatross
231
127
14.66
Thalassarche chrysostoma
Grey-headed albatross
1
1
0.38
Daption capense
Pintado petrel
8
5
1.88
Procellaria aequinoctialis
White-chinned petrel
2296
1396
36.84
Puffinus gravis
Great shearwater
1
0
0.00
Puffinus griseus
Sooty shearwater
30
10
3.76
Puffinus puffinus
Manx shearwater
7
3
1.13
Pterodroma mollis
Soft-plumaged petrel
2
1
0.38
Oceanites oceanicus
Wilson's storm-petrel
1930
1567
55.26
Phalacrocorax capensis*
Cape cormorant
889
648
4.51
Phalacrocorax lucidus
White-breasted cormorant
31
26
0.75
Morus capensis
Cape gannet
6299
5106
74.81
Stercorarius sp.
jaegger sp.
2
2
0.38
Stercorarius pomarinus
Pomarine jaeger
2
1
0.38
Stercorarius parasiticus
Arctic jaeger
1
0
0.00
Catharacta antarctica
Subantarctic skua
77
36
8.27
Xema sabini
Sabine's gull
4
1
0.38
Larus dominicanus vetula
Kelp gull
992
400
23.68
Larus cirrocephalus
Grey-headed gull
16
9
1.13
Sterna hirundo/paradisaea
Common/Arctic tern
194
110
18.42
Sterna maxima
Royal tern
2
1
0.38
Sterna sandvicensis
Sandwich tern
8
3
0.75
Chlidonias niger
Black tern
5
5
1.88
Arctocephalus pusillus
Cape fur seal
417
255
28.57
45
Diomedeidae, Albatrosses:
Three species of albatrosses were encountered, all migrants from the
southern ocean. The Atlantic Yellow-nosed albatross T. chlororhynchos breeds at
Gough Island and Tristan da Cunha group. They were absent in the north of the
survey area, a few sightings of T. chlororhynchos were made in deep water between
12o13'S and 13o25'S but the species became regular only south of 15oS in water
deeper than 100m and was absent in shallow water (< 50 m). Most individuals seen
at close range were immature and juvenile birds, but the proportion of adults
increased with latitude. The Black-browed albatross was very scarce, seen only four
times (all juveniles) in the extreme south of the survey area (south of 17oS) and the
Shy albatross (Thalassarche cauta) recorded in previous surveys in the same area
was not sighted during this survey.
The Grey-headed albatross (Thalassache chrysostoma) was seen once at
16o07'S in about 50 m of water. This latitude probably constitutes the northernmost
limit of the normal winter range of this species.
Procellariidae, Petrels and Shearwaters:
Out of six species of this group sighted during the survey, the Manx
shearwater (Puffinus puffinus) is a northern hemisphere migrant; the Great
shearwater (Puffinus gravis) is endemic to the Tristan and Gough group of Islands in
the south Atlantic. The other species are migrants from the sub-Antarctic region of
the southern ocean.
The Pintado petrel (Daption capense) was very scarce and present only in the
south, with 7 sightings (of 8 birds in total) all south of 16o26'S.
Only 7 sightings (of single birds) were made of the Manx shearwater (P.
puffinus), four between 12o15'S and 15o09'S off the shelf in water deeper than 400m.
The others sightings were all south of 16oS.
Only one sighting of Great shearwater (P. gravis) was made, the first one in Angolan
waters during the last four surveys. The sighting was of a single bird at 12o19'S
over mid shelf (108m depth).
The Sooty shearwater (Puffinus griseus), migrant from the sub-Antarctic, was
uncommon on the outer shelf and beyond the shelf break becoming more
widespread over the shelf south of 16oS south. There was, however, a noticeable
cluster of sightings (10 out of 24) in deep water (9 sightings between 500m and
920m) between 12o13'S and 12o23'S.
46
The White-chinned petrel (Procellaria aequinoctialis) was one of the most
abundant and widespread species encountered. It was found at low densities and
mostly offshore (outer-shelf and shelf break) north of 13oS. South of 15oS this
species is found regularly also inshore and in higher densities at depth greater than
100m and to the south.
The Soft-plumaged petrel (Pterodroma mollis) was seen for the first time
during these surveys, only in the extreme south of the survey area (17o20'S) and in
very deep water (the two sightings were in 1915 m and 1154 m respectively). This
species is not normally seen on the shelf.
Hydrobatidae, Storm-petrels:
Only one species of this group was recorded: the Wilson's storm petrel
(Oceanites oceanicus), a migrant from the southern ocean. This species was
widespread and abundant but with marked variations in densities. It was most
abundant at the shelf break and offshore between 10o50'S and 12o30'S, and south of
15o00'S, while far less common between 12o30 and 15o00'S. This species is mainly a
zooplankton surface-feeder and its association with frontal zones and surface slicks
is an indication of areas of zooplankton concentration at the surface. The observed
distribution pattern is remarkably similar to that found during previous surveys, an
indication that the zones of zooplankton availability at the surface are stable in space
from year to year.
Sulidae, Gannets:
The Cape gannet, Morus capensis, proved to be the most abundant and
widespread seabird during the survey, present in nearly 75% of the observations.
The proportion of young birds accounted for nearly half the total (3.3% of subadults,
27.5% of immatures and 14.2% of juveniles out of 1346 aged birds) and this is
consistent with observations made during previous cruises. This proves that Angolan
waters are an important feeding and wintering area for all age classes and might be a
key area for the survival of young birds of this vulnerable southern African endemic
species. North of 10o30'S and between 12o30' and 14o30'S densities were low. The
highest densities were observed in two clusters, one on the inner shelf (water
shallower than 50 m) between 10o30'S and 11o30'S as well as on the outer shelf
south of 15oS.
47
Phalacrocoracidae, Cormorants:
Only two cormorant species were recorded during the survey, and only in
coastal waters. The White-breasted cormorant (Phalacrocorax [carbo] lucidus) is
suspected to breed at several locations in the southern region from 13o15 to Baia dos
Tigres. The Cape cormorant (P. capensis), an endemic species from the Benguela
Current region, was observed only in the south (from about 14o13'S) and becoming
abundant around Baia dos Tigres. This species breeds and roosts in large numbers
at Baia dos Tigres and feeding aggregations counting tens of thousand birds were
observed in the bay as during previous years.
A third species, the Reed cormorant, (Phalacrocorax africanus), more associated
with fresh inland waters, was observed in Luanda bay but not included in the survey.
Pelecanidae; Pelicans:
The Great-white pelican (Pelecanus onocrotalus) was not seen at sea during
this survey, but several birds were seen onshore on the southeastern part of the
Island at Baia dos Tigres and this species probably breeds there. During previous
surveys the species has been seen in the same area as well as off several estuaries.
Stercoraridae, Skuas and Jaegers:
Two species of Jaegers (Stercorarius) were recorded in extremely low
numbers, the Pomarine jaeger (S. pomarinus) and the Arctic jaeger (S. parasiticus),
with 2 and 1 record of single individuals respectively. One additional record of two
jaegers, which could not be identified to species level, refers to probably St.
parasiticus or possibly to S. longicaudus. All three species have been recorded in
previous surveys and the low number of observations during the present survey is
probably due to the seasonality of migration of these northern hemisphere migrants.
The bulk of the palaearctic migrants is expected to pass through the region in
September to October.
The Subantarctic skua, Catharacta antarctica on the other hand, a visitor from
the southern ocean, was slightly more frequent than in previous surveys (48 sightings
of 77 individuals). The geographical distribution was remarkably similar to the
previous surveys: this species has a discontinuous distribution in Angolan waters at
this time of the year. South of 16oS, as further south in Namibian waters, the
Subantarctic skua is fairly common over the shelf. It is scarce but regular between
15oS and 16oS and absent further north. This corresponds to the known northernmost
distribution of the species in the Southeast Atlantic. However a small isolated area
48
about 350km further north, centered around the northern edge of the Quicombo Bank
(around 11o20'S) has been the site of a small cluster of observations of this species
during all previous surveys. This year seven sightings of single individuals were
made between 10o52'S and 12o13'S. Figure 2 illustrates this unusual distribution
pattern observed in the past 4 surveys.
-8.5
-8.5
-8.5
-8.5
-9
2002
2004
-9
2003
-9
-9
2005
-9.5
-9.5
-9.5
-9.5
-10
-10
-10
-10
-10.5
-10.5
-10.5
-10.5
-11
-11
-11
-11
-11.5
-11.5
-11.5
-11.5
-12
-12
-12
-12
-12.5
-12.5
-12.5
-12.5
-13
-13
-13
-13
-13.5
-13.5
-13.5
-13.5
-14
-14
-14
-14
-14.5
-14.5
-14.5
-14.5
-15
-15
-15
-15
-15.5
-15.5
-15.5
-15.5
-16
-16
-16
-16
-16.5
-16.5
-16.5
-16.5
-17
-17
-17
-17
-17.5
-17.5
-17.5
-17.5
11 11.5 12 12.5 13
13.5 14
11 11.5 12 12.5 13 13.5 14
11 11.5 12 12.5 13 13.5 14
11
11.5 12
12.5 13 13.5 14
Figure 2. Geographical distribution (Latitudes and Longitudes in decimal degrees) of the
subantarctic skua, Catharacta antarctica, during the past four surveys illustrating the
discontinuous distribution of this species in Angolan waters.
Laridae, Gulls:
The Grey-headed gull (Larus cirrocephalus), is a resident associated with
coastal and inland waters as well as along the coast in the vicinity of estuaries. It was
sighted on 5 occasions in shallow water (24 to 53m), around 12o29'S in the vicinity of
a river mouth and in the Baia dos Tigres area between 16o07'S and 16o29'S.
The Kelp gull (L. dominicanus vetula), is an endemic subspecies from
Southern Africa and the Benguela system was widespread throughout the survey
area. Kelp gulls were scarce in the north, becoming regular from 11o30'S and
abundant particularly inshore south of 16oS.
49
The Sabine's gull (Xema sabini), a northern hemisphere migrant, was sighted
only 3 times with a total of 4 individuals at 13o20'S, 16o07'S and 17o06'S. This low
abundance is probably due to the early date of the survey as this species' southward
migration through the area is peaking in September-October.
Sternidae, Terns:
Four of the five tern species recorded, are palearctic migrants (Sterna
hirundo, S. paradisaea, S. sandvicensis, and Chlidonias niger). S. hirundo was
widespread throughout the area but in much lower numbers than in some of the
previous surveys; again probably the effect of an earlier date on the abundance of
palearctic migrants. C. niger was very scarce with only 5 sightings of single
individuals. August must correspond to the extreme beginning of the migration
through this area (more than 300 individuals were sighted in September 2002).
The Royal tern (Sterna maxima) is a tropical species breeding in West Africa
and dispersing to southern Angola in summer. During the survey it was sighted only
twice at 14o19'S and 15o08'S. This low occurrence contrasts with previous surveys
when the species was regularly seen north of 13oS.
Marine mammals:
Cape fur seal: Arctocephalus pusillus:
Fur seals were distributed fairly uniformly in small numbers in the entire study
area but were more frequent over the inner shelf (depth < 150 m). Higher densities
were found south of 15oS and particularly near Baia dos Tigres which harbours a
fairly large non-breeding colony.
Cetaceans:
The summary of the cetacean sightings made during this part of the survey is
given in Table 2 and Fig 3.
The sightings of Killer whales (Orcinus orca) confirm the presence of this
species in Angolan waters. They have been observed in two previous surveys (2002
and 2003), which were the first confirmed records for this area.
The presence of Dusky dolphins (Lagenorhynchus obscurus) on the shelf in
the area of Baia dos Tigres is also a confirmation that the previous sightings of this
species in the same region during the last two surveys and represents the northern
limit of their normal range in the Southeast Atlantic. This species is probably the most
50
common small odontocete on the shelf of the Benguela upwelling ecosystem from
South Africa and Namibia. Its extended distribution in southern Angola south of the
Benguela-Angola Front is not surprising, however had not been documented before.
The lack of observation of dolphins of the genera Delphinus and Stenella was
surprising during this survey, and possibly a consequence of the anomalously cold
conditions prevalent in the region at the time of this survey.
Turtles:
Only one sighting of one single unidentified marine turtle was made during
this survey in (40m of water at 10o18'S, 13o25'E). This is in sharp contrast with
previous surveys when turtle sightings were regular particularly Olive Ridley
(Lepidochelis olivacea) turtles in approximately the same area, between 10o 23'S and
11o08'S.
Patterns of abundance:
On a broad scale and according to seabird and marine mammal distribution
observed during the previous surveys, southern Angolan waters can be divided in 4
distinct zones (the latitudinal limits given below are approximate and the description
of the patterns only for late winter and spring).
a) 9o30'S to 12o30'S
This area is characterized at this time of the year by:
· Presence of the Sooty shearwater P. griseus at low densities in deep water
· Presence of White-chinned petrel at low density over the outer shelf and
beyond
· Absence of Albatrosses, Cape Petrel, Cape cormorant
· Low densities of the Cape fur seal A. pusillus, on the shelf,
· Presence of Bryde's whale, Balaenoptera edeni.
In the southern half of this zone, a small area stands out at around 11o10'S 11o15'S
(the northwestern edge of the Quicombo bank). In this area seabird densities are
generally higher than either north or south of it. This is particularly the case for Cape
gannets and Wilson's storm petrels. This indicates a high availability of zooplankton
near the surface as well as higher availability of pelagic fish characteristics of a
divergent frontal zone, or local upwelling. This interpretation is supported by the
51
negative sea temperature anomaly extending offshore observed in this area year
after year. In addition the sightings of flotsam lines offshore in this area (contrasting
with flotsam being seen inshore further north or south) seems to indicate a surface
offshore transport located there. Also associated with this feature is the unexpected
presence of the Subantarctic skua (C. antarctica) noted during the previous 3
surveys as well as during this one (Fig X2). This species is otherwise found only
south of the Angola-BenguelaFront.
52
-8.5
-8.5
t.
Baleen whales
La
Baleen whales
-9.5
-9.5
-10.5
-10.5
-11.5
-11.5
-12.5
-12.5
-13.5
-13.5
-14.5
-14.5
-15.5
-15.5
-16.5
-16.5
-17.5
-17.5
-18.5
Depth (log scale)
10.8
11.3
11.8
12.3
12.8
13.3
13.8
-18.5
10000
1000
100
10
-8.5
-8.5
t.
Odontocetes
La
Odontocetes
-9.5
-9.5
-10.5
-10.5
-11.5
-11.5
-12.5
-12.5
-13.5
-13.5
-14.5
-14.5
-15.5
-15.5
-16.5
-16.5
-17.5
-17.5
-18.5
Depth (log scale)
-18.5
10.8
11.3
11.8
12.3
12.8
13.3
13.8
10000
1000
100
10
Figure 3. Humpback (grey circles) and Bryde's whale (black circles) distribution (Top) and
Pilot whale (black circles), Orca (open squares), Dusky dolphin (grey circles) and
Bottlenose dolphin (black diamond) distribution (Bottom).
53
b) 12o30'S to 14o30'S
This area is noticeable because of the general low densities of all seabird
species and is characterized by
· Lowest density of the four most abundant and widespread species, Wilson's
Storm petrel, White-chinned petrel, Kelp gull and Cape Gannet
· Absence of Balaenoptera edeni and Turtles
· Absence of Cape fur seal to 14oS, and very low abundance to 14o30'S
c) 14o30'S to 16o00'S
This area seems to constitute a transition zone with the appearance at low
density of some species more common further south such as Yellow-nosed albatross
Thalassarche chlororhynchos , Cape cormorant Phalacrocorax capensis and Pintado
petrel Daption capense and a slight increase in fur seal abundance.
d) South of 16o00'S
South of 16oS, the avifauna changes dramatically and is marked by a large
increase in density of many subantarctic species (Yellow-nosed albatross, Pintado
petrel, Sooty shearwater, Subantarctic skua, White-chinned petrel) as well as
Benguela current region endemics (Cape gannet, Cape cormorant, Kelp gull). The
density of Cape fur seal increases dramatically as well at around 16oS.
New sub-Antarctic species, more common in Namibian waters at this time of the
year, appear in this area (Black-browed albatross, Shy albatross) and marine
mammals characteristic to the Benguela upwelling region are also present
(Heaviside's dolphin inshore, Dusky dolphin on the shelf).
54
Table 2. Summary of cetacean sightings.
Species Number
Date
Local
time
Log
Depth
SST
Lat (dec ')
Long (dec ') Remarks
Balaenoptera edeni
1 28-Jul-05
15:56 1951 108 19.1 -8.792 13.074
Balaenoptera sp.
2 29-Jul-05
8:44 2092.3 32 19.4 -9.352 12.986
B.sp probable B. Edeni
Megaptera novaeangliae
1
29-Jul-05
11:02
2115
54
19.3
-9.475
12.977
Small size (sub adult)
Megaptera novaeangliae
1 30-Jul-05
11:40 2326.5 40 19.5 -9.923 13.177
Breaching
Unid.
2
30-Jul-05
15:18
2358
85
20
-10.062
13.115
Large baleen whale too far for ID
Megaptera novaeangliae
1
30-Jul-05
17:27
2381.2
529
22.1
-10.267
12.906
2 nm south
Megaptera novaeangliae
1 30-Jul-05
17:46 2384 265 22.1 -10.251 12.947
Possibly same individual as above
Megaptera novaeangliae
2
31-Jul-05
9:56
2497
52
19.5
-10.259
13.349
2 adults 10 m apart sounding in synchrony
Megaptera novaeangliae
2 31-Jul-05
10:08 2497.8 47 19.4 -10.252 13.358
2
adults possibly same individuals as above
Globicephala sp.
6-10 1-Aug-05 9:41 2698.2 650
20.1 -10.930 13.348
Associated with 8 Tursiops
Tursiops truncatus
8 1-Aug-05
9:41 2698.2 650 20.1 -10.930 13.348
Associated with Globicephala
Globicephala sp.
9
1-Aug-05
9:52
2700
696
19.7
-10.955
13.363
2 tight groups (4 and 5 indiv.) 200 m apart
Globicephala sp.
13-20 1-Aug-05 10:47 2703
495
19.4 -10.940 13.407
Orcinus orca
4
1-Aug-05
13:30
2717
103
18.9
-10.853
13.580
2 ad females, 1 large male, 1 young
Orcinus orca
2
1-Aug-05
13:43
2718
95
19.2
-10.844
13.595
2 medium size (ad Females?) 1' South of previous group
Balaenoptera edeni
1 2-Aug-05
13:04 2919 27 18.1 -11.432 13.704
About 300 m
Megaptera novaeangliae
1 3-Aug-05
16:52 3128 105 19.9 -11.931 13.545
Megaptera novaeangliae
4
6-Aug-05
17:24
3450
580
17.8
-13.506
12.515
4 large adults in a tight group
Megaptera novaeangliae
1 7-Aug-05
8:24 3538.9 43 17.1 -13.951 12.379
Megaptera novaeangliae
1 8-Aug-05
10:30 3725.2 404 16.6 -15.156 12.110
Breaching
Lagenorhynchus obscurus
6
9-Aug-05
16:03
3937
468
15.9
-16.113
11.568
Minimum count
Lagenorhynchus obscurus
15-20
11-Aug-05
10:00
4177
91
15.3
-16.691
11.601
15 to 20 duskies
Lagenorhynchus obscurus
30-50
11-Aug-05
10:08
4179
98
15.2
-16.700
11.570
In 2 groups 100 m apart
Lagenorhynchus obscurus
24 12-Aug-05
11:40 4375 132 14.3 -17.003 11.396
One
group
Globicephala sp.
12 13-Aug-05
10:47 4516 1058 14.4 -17.336 11.133
At least 1 very small young
55
Conservation aspects:
A number of seabirds present in Angolan waters in winter and spring are susceptible
to by catch by long line fisheries (as well as direct catch from small crafts). These include
particularly all species of albatrosses, and some petrels and shearwaters as well as the Cape
gannet. By catch by long-line fisheries in the southern hemisphere has impacted widely on
many species of seabirds and, despite major international efforts to limit the problem, is
threatening the survival of several species of albatrosses and petrels. In Namibia, the Cape
gannet continuing population decline and the deterioration of its conservation status (the
population declined by half in the past decade) has been attributed to trophic factors (and
particularly the decline in the sardine stock) as well as increased by catch by long-line
fisheries, which have developed in Namibia since the early 1990s.
The sightings during the 2002 survey of small vessels using floating lines to catch
seabirds in the southern part of the area (and targeting both White-chinned petrels and Cape
gannets, together with the realization of the importance of Angolan waters for all age classes
of gannets at this time of the year causes some concern. A high incidence of Cape gannets
sighted in southern Angola during the 2003 and 2004 surveys (particularly around Tombua)
with remnants of lines and hooks in their beaks attests to the reality of this potential threat
which might be impacting negatively on the threatened Namibian gannet population.
The results gathered during the four surveys have shown that southern Angola is a
key area for wintering gannets and particularly important for young birds. The Cape gannet is
an endemic to the region with only six breeding sites worldwide, including three in Namibia.
The Namibian population has declined drastically in the past decade and the recruitment of
young birds seems to be insufficient to sustain the population. Given the importance of
southern Angola to young gannets revealed by the last four surveys it seems important that
Angola be included and involved together with Namibia and South Africa in a joint
conservation effort regarding these seabirds.
The following figures give examples of distribution of the main species using all
records (presence absence) and of the highest densities of the most common and
widespread species, using the 10-minute counts only. These data are plotted against
geographical coordinates as well as in latitude-depth (on a log scale) plots to visualize the
distribution patterns on and off the shelf.
56
-8.5
-8.5
t
.
t
.
-9
-9
La Thalassarche chlororhynchos
La
Thalassarche chlororhynchos
-9.5
-9.5
-10
-10
all
all
-10.5
presence
-10.5
presence
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
t
.
-9
Daption capense
-9
La
La
Daption capense
-9.5
-9.5
-10
-10
all
all
-10.5
presence
-10.5
presence
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 4. Distribution of the Yellownosed albatross (top) and the Pintado petrel (bottom).
57
-8.5
-8.5
t
.
t
.
-9
Procellaria aequinoctialis
-9
La
La
Procellaria aequinoctialis
-9.5
-9.5
all
-10
-10
all
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
Procellaria aequinoctialis
t
.
-9
-9
Procellaria aequinoctialis
La
La
-9.5
-9.5
1-10
1-10
-10
11-25
-10
11-25
26+
26+
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 5. Distribution and patterns of abundance of the White-chinned petrel.
58
-8.5
-8.5
t
t
.
-9
La
Oceanites oceanicus
-9
La
Oceanites oceanicus
-9.5
-9.5
all
-10
-10
all
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
Oceanites oceanicus
t
.
-9
-9
Oceanites oceanicus
La
La
-9.5
-9.5
1-10
1-10
-10
11-25
-10
11-25
26+
26+
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 6. Distribution and patterns of abundance of the Wilson's storm-petrel.
59
-8.5
-8.5
t
.
t
.
-9
Puffinus puffinus
La
-9
La
Puffinus puffinus
-9.5
-9.5
all
-10
-10
all
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
t
.
-9
Puffinus griseus
-9
La
La
Puffinus griseus
-9.5
-9.5
all
-10
-10
all
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 7. Distribution of the Manx shearwater (top) and the Sooty shearwater (bottom).
60
-8.5
-8.5
t
.
t
.
-9
Phalacrocorax capensis
-9
La
La
Phalacrocorax capensis
-9.5
-9.5
all
-10
-10
all
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
t
.
-9
Catharacta antarctica
-9
La
Catharacta antarctica
La
-9.5
-9.5
-10
-10
all
all
-10.5
presence
-10.5
presence
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 8. Distribution of the Cape cormorant (top) and the Subantarctic skua (bottom).
61
-8.5
-8.5
t
.
t
.
-9
Morus capensis
-9
La
La
Morus capensis
-9.5
-9.5
all
-10
-10
all
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
Morus capensis
t
.
-9
-9
Morus capensis
La
La
-9.5
-9.5
1-25
1-25
-10
26-75
-10
26-75
76+
76+
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 9. Distribution and patterns of abundance of the Cape gannet.
62
-8.5
-8.5
t
.
t
.
-9
Larus dominicanus
-9
La
La
Larus dominicanus
-9.5
-9.5
all
-10
-10
all
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
Larus dominicanus
t
.
-9
-9
Larus dominicanus
La
La
-9.5
-9.5
1-5
1-5
-10
6-25
-10
6-25
26+
26+
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 10. Distribution and patterns of abundance of the Kelp gull.
63
-8.5
-8.5
t
.
t
.
-9
Arctocephalus pusillus
La
-9
La
Arctocephalus pusillus
-9.5
-9.5
all
-10
all
-10
presence
presence
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
-8.5
-8.5
t
.
Arctocephalus pusillus
t
.
-9
-9
Arctocephalus pusillus
La
La
-9.5
-9.5
1-3
1-3
-10
4-10
-10
4-10
11+
11+
-10.5
-10.5
-11
-11
-11.5
-11.5
-12
-12
-12.5
-12.5
-13
-13
-13.5
-13.5
-14
-14
-14.5
-14.5
-15
-15
-15.5
-15.5
-16
-16
-16.5
-16.5
-17
-17
-17.5
-17.5
Long.
Depth m (Log scale)
-18
-18
10.8
11.3
11.8
12.3
12.8
13.3
13.8
1000
10
Figure 11. Distribution and patterns of abundance of the Cape fur seal.
64
Document Outline
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