Optimal Harvest Age for Giant Clam, Tridacna derasa: An Economic Analysis

Abstract

This paper analyzed the optimal harvest time (replacement cycle) to maximize economic returns for the giant clam, Tridacna derasa. The optimal harvest age ranged from no production to 13.2 years if only shell was assumed to be saleable, from no production to 9.2 years if only adductor muscle was assumed to be saleable, and from no production to 10.5 years if only other meat was assumed to be saleable. If all clam products were assumed to be saleable, the optimal harvest age ranged from no production to 10.7 years. If only meat was assumed to be saleable, the optimal harvest age ranged from no production to 9.0 years. The results indicate that clam farming can be profitable if prices of clam products are high or juvenile and annual operating costs are low. If all clam products can be sold, clam farming is generally profitable. If only meat can be sold, clam farming is profitable only if the high production costs are low and the prices of the meat products are high. Marketability of shell is an important factor affecting optimal harvest age and the profitability of production.