Gulf of Mannar Marine National Park

Gulf of Mannar Marine National Park protects 21 small islands and the coral reefs beside them, 1 to 10 km off the east coast of Tamil Nadu along a 160 km stretch between Thoothukudi and Dhanushkodi. Established in 1980 and covering 560 sq km, it forms the core of the Gulf of Mannar Biosphere Reserve. Visitors can enter the park only on glass-bottom boat rides.

Mangroves dominate the islands' intertidal zones, while seagrass and seaweed beds feed dugongs, the park's flagship mammal, along with green and olive ridley turtles. The Gulf holds about 510 fin fish species, some 23% of those in Indian waters, together with 117 coral species, dolphins and whales. The waters around Kurusadai island hold three seagrass species found nowhere else in India, and Ptychodera fluva, a living fossil linking invertebrates and vertebrates, is known only from there. Yet large areas of reef are in generally poor condition, and coral mining has left Vilanguchalli island 1 m below mean low tide.