Molluscan Biology and Taxonomy

Molluscs belong to the large and diverse phylum Mollusca, which includes a variety of soft-bodied invertebrates well-known as decorative shells or as seafood. They range in size from less than 1 mm to more than 15 m (for example the giant squid) and their population density may exceed 40,000/m2 in some areas. Three classes of the phylum Mollusca namely, Gastropoda (snails, limpets, whelks and slugs), Bivalvia (oysters, mussels, clams, scallops, and cockles) and Cephalopoda (squids, cuttlefishes, and octopuses) are of fisheries interest. About 3270 species have been reported from India belonging to 220 families and 591 genera. Among these the bivalves are the most diverse (1100 species) followed by cephalopods (210 species), gastropods (190 species), polyplacophores (41 species) and scaphopods (20 species)