The Gulf of Mannar endowed with three distinct Coastal ecosystems namely coral reef, seagrass bed and mangroves is considered one of the world’s richest region from a marine biodiversity perspective, is known for its unique biological wealth and is a store house of marine diversity of global significance.
Mangroves dominate the intertidal zones of the park islands. They consist of species of the genera Rhizophora, Avicennia, Bruguiera, Ceriops and Lumnitzera. Mangroves: photo gallery. The introduced tree genus Prosopis is dominant on land in all the islands. The flowering herb Pemphis acidula is the only endemic plant species. 12 species of sea grass and 147 species of seaweeds were recorded. This vegetation provides important feeding grounds for the vulnerable marine mammal, the dugong, endangered green turtles and vulnerable olive ridley turtles. The dugong, a vulnerable marine mammal, is the flagship mammal of the park. It is an important habitat for the cetaceans: Indo-Pacific bottlenose dolphin, finless porpoise, spinner dolphin, common dolphin, Risso's dolphin, melon-headed whale, and dwarf sperm whale. Larger whales include sperm whale, minke whale, Bryde's whale, sei whale, and critically endangered species including humpback whale, fin whale, and blue whale. Four species each of shrimp and lobster, 106 species of crab, 17 species of sea cucumber, and 466 species of mollusc including 271 gastropods, 174 bivalves, 5 polyplacophorans, 16 cephalopods and 5 scaphopods, 108 species of sponge, and 100 species of echinoderm occur in the Gulf.
