The Gulf of Mannar Biosphere Reserve is located on the south eastern tip of India and is near Sri Lanka. The Gulf of Mannar is has a hugely marine ecosystem, which includes coral reefs, salt marshes, algae communities, mangroves, and sea grasses, among many others. Cephalopods are key components of marine trophic webs, where they constitute major food resources for a large variety of predators including fish, other cephalopods, marine mammals, and seabirds. Description of Squids, Cuttlefish and Octopi. This study are revealed the biology, methods of fishing and economic importance of cephalopods.