Brachyuran crabs of Gulf of Mannar

Coral reef ecosystems are tropical, shallow water marine ecosystems, largely restricted to ttJe area between the latitudes 300N and 300S of equator. Even though, they occupy less than 0.2 % of the ocean floor, they contain perhaps 25% of the ocean's species (IUCN/UNEP, 1985). Thus the coral reef ecosystems are well known for their species richness and also complexity. It is quite remarkable that an environment with so small an area, has so much life and so many species and thus diversity. Typically they contain number of specialised species representing almost all the groups of marine animals