Turbo and Trochus resources

Abstract

Among the commercially important molluscs in the Andaman and Nicobar Islands, Trochus nilotkuS Linn6 and Turbo marmoratm Linne occupy a prominent position because of their abtmdance and economic value. Commercial exploitation of these shells may be deemed to have started from 1929 (Panikkar, 1938) although, even earlier to this, Japanese fishermen from Singapore had been fishing for them around these islands unauthorisedly (Rao, 1939). Of these two species, Trochus niloticus was foimd to be more abundant in all the islands surveyed. Though there were good landings of these shells in the earlier years, they started declining in later years, which prompted the Andaman Administration to appoint a Special Officer to carry out scientific studies on the fishery. A consolidated report on the shell fishery of these islands during 1930-35 was published by Rao (1939). Amirthalingam (1932), Setna (1933), Prashad and Rao (1933,1934), Rao (1936 a, b, 1937, 1941) and Panikkar (1938) made more detailed observations on the shell fishery of the Anda- mans, with accoimts of the feeding habits, breeding seasons, size at sexual maturity, growth rate and other biological details of T. niloticus. Anon (1939) has briefly reviewed the results of the investigations made by the Zoological Survey of India in Andamans. Menon (1976), Cbatterjee (1976) and Appufcuttan (1977) have described the importance of Trochus and Turbo in the shell-craft industry. The Trochus and Turbo resources of the different islands were surveyed during 1978 by the Central Marine Fisheries Research Institute, the results of which, along with notes on the fishery, are presented here.