Marine Conservation Reserve around Lakshadweep Archipelago

by Lalitha Vaidyanathan

Mumbai, Jun 10 (PTI) India's first Marine Conservation
Reserve, the result of a three-year-long study on Lakshadweep
Islands and the local community there, will soon come up
around the region, off the west-coast of Kerala.

Bombay Natural History Society (B.N.H.S.) in
collaboration with the local community and administration is
in the process of forming a strong knowledge-based network,
according to Assistant director B.N.H.S. Deepak Apte.

The project, initiated in 2005, has now emerged as the
most active conservation initiative in the country.

B.N.H.S. along with L.E.A.D. International and a team of
experts from across the country conducted a prolonged research
in the Lakshadweep Archipelago's local community in the last
three years during which they assessed the importance of the
giant clam (Tridacna maxima and T squamosa) in the local
economy, Apte told P.T.I.

The giant clam, which the study found also helps
maintain a healthy eco-system, is included in the Schedule I
of the Wildlife (Protection) Act 1972.

The local panchayat has formally forwarded a proposal
for the marine reserve to the Lakshadweep Administrator who is
expected to forward it to Ministry of Environment and Forests
(MoEF).

The local Panchayat is currently the biggest proponent
of the project after the research team explained to the local
fisherfolks and others, through over 400 consultations in the
last three years, the importance of conservation from the
point of view of their livelihood, Apte said.

The exercise began with the studying two species of the
giant clams -- Tridacna maxima and Tridacna squamosa -- which
occur in shallow waters and their relation with the lagoon
ecology.

Project findings established close link between the clams
and the bait fish habitat (which is used for tuna fishing).

Thus, if people need to safeguard the bait fish, which is
vital for tuna fishing, they need to protect lagoon reef.
Health of lagoon reef could be easily monitored through the
giant clams, Apte said.

"We have studied 24 islands and the comprehensive data
available on them concluded that we need 60 giant clam adults
per hectareand in some islands, however, we have clam density
as low as 18 per hectare," he said.

Giant clams prefer the dead flat tops (with live coral on
all sides) and to lesser extent, the walls of the coral
species Porites lutea, within a narrow range of water depth in
the lagoon.

Such specific habitat requirements leave very little
potential spacefor the species in the lagoon. Also mortality
in juveniles is highly influencing the populations.

U.K.-based Darwin Institute has been funding the project
and is impressed with the detailed plan and community
involvement in conservation of the bio-diversity in the
region, Apte said.

The protected area will be located in the Agatti, about
500 km from the mainland of India, said Apte, who recently
received Whitley Cosnervation Award by Sheers Foundation.

"The clam T maxima recruitment is adult density dependent
and need between 60 to 100 adult clams per hectare for
successful recruitment," he said.

Population structure of this species was skewed from
normal distribution towards greater size classes probably due
to the rapid growth of juveniles and extremely slow growth
leading to higher proportions of mid-sizes, conservationists
said.

Convict surgeonfish (Acanthurus triostegus) is the single
most dominant browser inside lagoon waters. Thus role of this
species in maintaining microhabitat for new recruits of most
crucial part of T maxima life cycle.

"Population studies on convict surgeonfish will be useful
for management of giant clams. It is the main table fish for
locals in Lakshadweep thus further studies are required to
assess the impact of harvesting of this fish specieson T
maxima recruitment, he said.

"Giant clams play a crucial role in lagoon ecology by
releasing large amounts of organic matter in to the lagoon
water on which many fishes feed," he said.

Under the species conservation plan, Apte and his group
have recommend for a long term monitoring of T maxima to make
population projections.

Another important finding was that the giantclams grow
exclusively on massive corals Porites lutea, itsdestruction
and removal must be avoided. These massive corals are usually
removed for easy navigation within lagoon.

Opening of new channels through breaking of reef crest
must not be done as it can alter the lagoon ecology
significantly as seen in Minicoy island. This can not only
affect T maxima but also coral community as well, Apte said. -
PTI.