CORDIO Status Report 1999.pdf

grow, but damage and loss of transplanted corals due to
wave action is common (Birkeland, 1979; Bowden-
Kerby, 1996; Clark, 1995; Harriott, 1988). Some of the
methods applied so far to fix corals on the seabed
involve the use of underwater epoxy glue (Kaly, 1995;
Yap, 1992), terracotta tiles (Plucer-Rosario, 1977;
Birkeland, 1979), steel bars hammered into the substrate
(Guzmán, 1991) or large concrete structures placed on
the seabed (Clark, 1995). These methods are labourintensive
and require SCUBA diving and expensive
materials and equipment, and therefore their application
may be restricted to the reefs with the highest
economic value, such as sites for dive tourism and
recreation. However, most of the countries that are most
seriously affected by coral reef degradation have limited
resources for natural conservation, and it is clear that
large-scale coral reef restoration can never be a realistic
option in developing countries unless simpler methods
are developed, methods that can be applied by the local
community of reef-users without specialist skills and
without great investments in materials.
The need for more cost-effective methods for reef
rehabilitation has led to the suggestion that corals
should be transplanted to low-energy environments
without being attached (Woodley, 1989; Yap, 1990;
Kojis, 1981). Studies on transplantation of unattached
corals performed so far (Birkeland, 1979; Bouchon,
1981; Bowden-Kerby, 1996; Lindahl, 1998; Harriott,
1988; Plucer-Rosario, 1977) have yielded variable results,
possibly due to the different species, methods and
habitats that have been used.
Staghorn corals and other branching corals in the
genus Acropora generally show good survival and rapid
growth after transplantation, and the most promising
results stem from studies of unattached staghorn corals
placed in shallow habitats protected from strong wave
action (Bowden-Kerby, 1996). However, this growth
form has often been dislodged and killed by strong
wave action after transplantation (Bowden-Kerby, 1996;
Harriott, 1988). Likewise, Clark and Edwards (1995)
found higher mortality of branching acroporids transplanted
to a high-energy environment compared to
species with massive growth forms. The branching
growth form and small area of attachment of staghorn
corals makes them vulnerable to strong water movement
even if the corals are firmly attached to a stable
substrate, whereas in a protected or moderately exposed
environment this growth form has the ability to survive
and attain stability even on loose substrate (Gilmore,
1976; Bowden-Kerby, 1996; Tunnicliffe, 1981).
In a recent two-year study, aimed at developing
simple and cost-effective methods for reef rehabilitation,
transplanted staghorn corals showed good survival and
growth on unconsolidated substrate in a moderately
exposed environment (Lindahl, 1998). The method of
tying the corals together on strings before placing them
on the seabed was shown to significantly increase their
ability to colonize the target area.
Staghorn corals are common in shallow waters on
many reefs worldwide; they grow rapidly and have a
natural ability to reproduce through fragmentation and
to colonise unstable substrate. Connell (1985) noted that
small patches and clearings within existing coral
populations are invaded quicker by branching and
fragmenting species than by massive growth forms.
Therefore, staghorn corals are especially suitable for
rehabilitation purposes, not only because of their
capacity to populate a specific target area, but also for
the possibility of rapid regeneration of clearings and
other damages on the source populations. This may not
be the case with most of the slow-growing massive
corals, and that should make them less suitable for
transplantation. However, the usefulness of staghorn
corals may be restricted to habitats with ”sufficient”
shelter from wave action.
IDEAS FOR FUTURE RESEARCH
Experimental data is needed on the suitability for
transplantation of a wide range of coral species in
different habitats (i.e. depth, wave-exposure, water
quality and sediment structure), and on the effects of
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