Clark and AJ Edwards 1995 Coral transplantation as an aid to reef rehabilitation- evaluation of a case study in the Maldive Islands

Abstract. As part of a study of reef rehabilitation, whole
coral colonies (primarily Acropora, Pocillopora, Porites,
Favia and Favites) were transplanted and cemented in
place onto three approximately 20 m 2 areas of Armorflex
concrete mats on a 0.8-1.5 m deep reef-flat in the Maldives
which had been severely degraded by coral mining.
Growth, in situ mortality, and losses from mats due to
wave action of a total of 530 transplants were monitored
over 28 months. Natural recruitment of corals to both the
transplanted Armorflex areas and concrete mats without
transplants was also studied. Overall survivorship of
corals 28 months after transplantation was 51%. Most
losses of transplants due to wave action occurred during
the first 7 months when 25% were lost, with only a further
5% of colonies being lost subsequently. Within 16 months
most colonies had accreted naturally to the concrete mats.
Thirty-two percent of transplants which remained
attached died with Acropora hyacinthus and Pocillopora
verrucosa having the highest mortality rates (approx. 50%
mortality over two years) and Porites lobata and P. lutea
the lowest (2.8 and 8.1% mortality respectively over two
years). Growth rates were very variable with a quarter to a
third of transplants showing negative growth during each
inter-survey period. Acropora hyacinthus, A, cytherea and
A. divaricata transplants had the highest growth rates
(colony mean linear radial extension 4.15-5.81 cm y-l),
followed by Pocillopora verrucosa (mean 2.51 cm y-l).
Faviids and poritids had lowest growth rates. Favia and
Favites showed the poorest response to transplantation
whilst A cropora divaricata, which combined a high growth
rate with relatively low mortality, appeared particularly
amenable to transplantation. Natural recruitment did not
differ significantly between concrete mats with and without
transplanted corals. ‘Visible’ recruits were first recorded
10 months after emplacement of the mats and were
predominantly Acropora and Pocillopora. On near vertical
surfaces their density was almost 18 m -2. Recruits grew fas producing many 20-30 cm diameter colonies on the mats
within 3.5 years. Growth and survival of transplants are
compared with results of transplantation studies in other
locations. We conclude: (1) species transplanted should be
selected with care as certain species are significantly more
amenable than others to transplantation, (2) the choice of
whether fragments or whole colonies are transplanted may
profoundly influence survival, (3) considerable loss of
transplants is likely from higher energy sites whatever
method of attachment, (4) transplantation should, in
general, be undertaken only if recovery following natural
recruitment is articel here/ disini