Meretrix meretrix (Asiatic hard clam)

It has a hard shell covered with a delicate, brownish-greyish periostracum, and its postero dorsal margin has a greyish-blue- bluish-brown band. The shell is triangular to oval in shape. The posterior margin is slightly more pointed. It is equivalved, having no gape when closed. The lunule is not clear and the ligament is short. It has an umbo on anterior side. The shell exterior is white in colour. There is light purple or pink colouration along the radial lines. Hinge plate is hard. There are three cardinal teeth on the left and right valves.Meretrix meretrix is a large bivalve which is distributed in Philippines, Australia, Singapore, Indonesia, Thailand, South Africa, Malaysia, Indonesia, Vietnam, China, Japan, Korea and Papua New Guinea. It is also widely spread along the west and east coasts of India. It occurs along the west coast in Kalbadevi and Bhatea creeks of Maharashtra; Chaporal, Sal, Mandovi and Zuari estuaries of Goa; Kalinadi, Tadri and Coondapur of Karnataka and Thellicherry and Ashtamudi lake of
Kerala. Along the east coast, it occurs in major estuaries of Tamil Nadu, Andhra Pradesh and in the Chilika Lake. It inhabits marine and estuarine habitats. It is distributed in the sandy mud flats upto a depth of 4 m.
Life span is 7-8 years with size ranging from 14.6-91 mm. They are dioecious. It followed a clear pattern of annual reproductive cycle with a long breeding period, extending from September to January in west coast and during September and May along the east coast of India . Gonads of female have light brown colour and male gonads have milky white colour when mature.