Coral
V O LU M E 1
I S S U E 1
ReefTargeted Research & A D V I S O R Y B R I E F
Capacity Building for Management
Reef restoration following the Asian
tsunami tragedy
Recommendations
showed no detectable impact whereas others (e.g. Dutch
In the short-term the primary concern in Indonesia,
Bay, Trincomalee) were devastated. Even so, with present
Thailand, Sri Lanka, India, Maldives and other affected
techniques it would be very costly to restore all areas and
nations is the human toll, the health and sustenance of
some are likely to recover naturally. Impacted areas will
survivors, and the rebuilding of livelihoods for those
need to be carefully prioritised and scarce resources focused
coastal communities devastated by the 26 December 2004
to assist recovery in those areas which will benefit most
tsunamis. However, longer term reconstruction efforts
from both a biological and economic viewpoint.
will need to examine requirements for rebuilding dam-
aged economic sectors,
Before any restoration is undertaken, the damage caused
such as fisheries and
to reefs by the tsunami needs to be assessed in detail.
tourism, and rehabilitat-
Assessments should not only evaluate the extent of damage
ing the natural systems
but also the potential for natural recovery at each impacted
on which they depend.
site. In some countries (e.g. Thailand, Sri Lanka, Maldives) a
preliminary or detailed assessment has already been done.
Studies of coral reefs fol-
Standard rapid reef assessment techniques are ideal for this.
lowing hurricanes and
Unless detailed baseline data are available, the difficulty lies
typhoon impacts suggest
in determining what damage was caused by the tsunami
that, in general, natural
and what damage existed before. However, certain impacts
recovery processes work
such as presence of large debris (trees, doors, cars, etc.) on
well and, given limited
the reef and large chutes of sand and mud swept off coastal
resources, restoration
areas and smothering the reef are likely to be tsunami-
should be considered
related. Other common tsunami impacts are huge massive
with circumspection.
corals broken or overturned. Damage due to anthropogenic
The cost effectiveness of
impacts such as dynamite fishing, sewage discharges, etc.
restoration interventions
needs to be distinguished from that due to the tsunami.
Source: ReefBase
will depend on a number
Reefs are more likely to recover from impacts due to natural
of factors, including the source and extent of damage, the
disturbance than from human impacts and the former may
extent to which these reefs underpin the health and liveli-
also be more amenable to restoration efforts. Impacts due
hoods of heavily affected local communities, such as arti-
to anthropogenic causes cannot easily be remedied unless
sanal fishers and those dependent on local tourism, and
coastal management measures have also been introduced to
the estimated time lags for natural recovery. In the light
eliminate the source of stress. In the absence of such meas-
of these considerations, we make some general recom-
ures, restoration should not even be considered.
mendations concerning reef restoration targeted at
enhancing natural recovery.
Construction in coastal areas often generates sediment
which damages near-shore reefs. Thus coastal reconstruc-
From the evidence we have seen, quite extensive areas of
tion, if not carried out sensitively, may exacerbate damage
coral reef have been damaged with some 13% of 174 rep-
to reefs caused by the tsunami or kill corals that survived
resentative sites surveyed in detail in Thailand deemed to
the tsunami. During reconstruction the opportunity
be heavily impacted. On the other hand, almost 80% of
should be taken to reduce any anthropogenic stresses that
sites were found to have been little impacted. Further, aerial
may be impacting the natural reefs. This is extremely
images show that coral reefs (and mangroves) provided
important to ensure the recovery of the reefs. Such
significant protection to coastlines, with damage being
stresses might include sewage pollution, anchor damage,
greater where these were absent or degraded. Interestingly,
diving pressure, over-fishing, sedimentation, etc.
reef damage was often localised. For example, the coral
Overfishing is suspected to be a key factor in reducing the
reef in the north of Patong Bay in Phuket, Thailand was
recovery potential of reefs to various impacts, leading in
almost undamaged whereas that in the south part of the
some cases to phase-shifts from highly productive, biodi-
bay was severely impacted. Similarly, in Sri Lanka some sites
verse, coral-dominated communities to relatively unpro-
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ductive, less biodiverse, algal-dominated communities. As
established (seeded from nearby reefs) that are different
cogently argued by Daniel Pauly in Nature, re-investing in
to those that existed on the sand prior to the tsunami. This
boats and gear to rebuild local fisheries to pre-existing
may result in unwanted changes in community structure.
levels in areas, which in general are already grossly over-
fished, will not provide a long-term sustainable solution
As soon as possible after assessment, various non-contro-
(Nature, Vol. 433, February 2005). Where feasible, the
versial steps can be taken at sites prioritised for rehabilita-
opportunity should be taken to develop exit strategies
tion. These fall under the heading of "triage" (i.e. stop the
and alternative livelihoods for fishers who wish to leave
bleeding) and involve trying to limit damage. Volunteer
the sector, thus reducing overcapacity and fishing pres-
divers can assist in this work:
sure, and increasing the resilience and recovery potential
Returning overturned colonies to original positions,
of the coral reefs. Coastal managers should also take this
repairing cracked massive colonies, and reattaching
opportunity to correct land-based pollution and other
detached coral colonies directly with epoxy com-
sources of stress on their precious coral reef resources.
pounds or cement. This is perhaps most important
for large slow-growing massive corals, but also for
There is a range of reasonable actions which can be under-
branching corals and sea-fans.
taken to aid recovery. Where there is foreign debris (e.g. tree
Broken branches and fragments of branching corals,
trunks) on the reef, which is moving around and causing
for species which do not naturally reproduce by frag-
further damage by breaking corals, this should be removed
mentation, can be rescued and reattached or moved
as soon as possible. Where there are large chutes of sedi-
to safety in in-situ nurseries for later reattachment.
ment, these may be relatively quickly swept off by normal
These are likely to die if left where they are.
currents and wave action in exposed areas but may require
mechanical removal in protected embayments. Corals
Beyond triage, there are various techniques like coral cul-
buried for a month are likely to be dead and so such chutes
ture, coral transplantation, etc. that can be used to assist
are primarily of concern if they are creating turbidity which
or kick-start natural recovery. For example, broken
is impacting surviving corals or retarding natural recovery
branches can be cut into small fragments a few polyps in
in adjacent areas. An attempt to estimate the natural rate
size (called "nubbins") and these can be cultured in nurs-
of sediment loss from chutes should be made during the
eries to produce thousands of small colonies which can
assessment phase. If natural sediment removal is relatively
then be planted out on the reef. Such techniques are
fast and not causing collateral damage then such chutes are
expensive, time-consuming, require expert advice and
best left alone. Where necessary chutes can be sucked off the
have had limited testing in the field. Local needs and pri-
reef using a suction dredge but care must be taken that
orities will dictate whether they might be considered.
dredged sediment does not cause problems elsewhere.
Above all it must be stressed that restoration has only ever
If large areas of coral rubble have been generated by the
been attempted on the scale of a few hectares, whilst the
tsunami, these are unlikely to recover naturally if the rubble
areas impacted by the tsunami far exceed this.
is unstable and moved around by waves and currents.
Rehabilitation of such areas can be assisted by deposition
Every restoration project can potentially contribute lessons
of large limestone boulders which stabilise the substrate
from which future projects can learn. Unfortunately, few
and allow natural recolonisation. Such techniques have
do, because monitoring of the progress of recovery is sel-
been used successfully to rehabilitate areas impacted by
dom carried out systematically; this is because funding is
dynamite fishing in Indonesia. Costs and priorities need
generally short-term and focused on doing restoration
to be determined locally as any such intervention
rather than evaluating its success in the long term. The
demands considerable funding. An alternative, if the areas
importance of systematic long-term monitoring of any
are small, is to remove the loose rubble. Diver operated
restoration attempted cannot be overemphasised.
suction dredges driven by compressed air from a surface
compressor can be used to remove small patches.
In general, restoration actions should be well-considered
and thoroughly costed. They should only be undertaken
Good scientific approaches to reef restoration can
once the source of stress is removed, and should be con-
enhance its cost-effectiveness. For example, studies of
servative in scope. We would urge those considering reef
local currents can identify reefs which are likely to act as
restoration to keep the lines of communication open
sources of coral larvae and others which are likely only to
with this and other groups of practitioners and to share
be sinks. Restoration interventions at source reefs are likely
the results of assessments and monitoring so that all can
to be more effective than restoration at sink reefs.
benefit from lessons learned.
Some species of branching coral form thickets on sand
GEF/World Bank Coral Reef Targeted Research and
(e.g. Acropora formosa). These are likely to have been
Capacity Building for Management
severely impacted by the tsunami. To restore these com-
Restoration and Remediation Working Group
munities one can anchor small clusters of those acroporid
Dr. Alasdair Edwards, Chair
branching coral species, which live naturally on sand to
University of Newcastle
Newcastle upon Tyne
the seabed. If one tries to stabilize such sand environments
Email: A.J.Edwards@newcastle.ac.uk
with artificial structures, there is a risk of upsetting the
local hydrodynamics. Also, introducing artificial structures
www.gefcoral.org
will almost certainly lead to coral communities being
February 2005

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