'Central Marine Fisheries Research Institute, Kochi'
Abstract
The coral reefs are distributed in the tropical
regions and cover less than one percent of the
earth’s surface, but provide habitat for many species
in the marine realm. The majority of reef building
corals are found in tropical and subtropical waters
and typically occur between 30° N and 30° S
latitudes (Fig. 1). Coral reefs are greatly valued due
for their beauty, biodiversity it encompasses and
the products and services they provide to human
society. The coral reefs are made of calcium
carbonate secreted as skeletal material by the coral
polyp. Coral polyps live in association with
intracellular algae (zooxanthellae), which provide
additional nutrition to the coral in its life processes.
The association of coral polyp with zooxanthellae,
restrict its distribution in waters up to the depth of
100 meters where sunlight would be available for
the photosynthetic zooxanthellae. The worldwide
of zooxanthellate corals in the different distribution
eco-regions is a unique underwater ecosystem and
provides annual net economic benefit around 30
billion dollars (Buddemeier et al., 2004 Pew Center
on Global Climate Change, 44p). However, coral
reefs are most vulnerable to Climate Change due
to the stenothermic nature of coral polyps
