Recent innovations in cultivation of edible molluscs in Taiwan, with special reference to the small abalone Haliotis diversicolor and the hard clam Meretrix lusoria

Abstract

Annual production and culture area of small abalones and hard clams have surprisingly increased in recent years. The factors contributing to this increase, aside from heavy demand and high price, include new techniques in catching the tiny clam seed (0.5 mm in size), success in mass production of seed of both species in hatcheries, better understanding of the molluscs' biology as well as their response to environmental changes, improved management of water quality to provide the optimal growth conditions, cheap and easy supply of Gracilaria for abalone feed, use of powdered formulated feed for hard clams, application of chicken manure and rice bran to enrich the water, intermediate harvest of animals of marketable size, and control of predators. However, major constraints to further development and expansion of molluse cultivation remain, including water pollution from industrial wastes, limited area with suitable water supply, strict regulations on the use of seashore land and littoral zone, and the lack of export market. Other species of molluscs, including the oyster Crassostrea gigas, the short-necked clam Comphina veneriforms, the purple clam Soletellina diphos, the cockle anadara granosa, and the small freshwater clam Corbicula, have potential for further expansion if problems of seed supply, water pollution, control of disease, and market price are properly solved.