Not AvailableAmong 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 Administr...