Abstract

Although Manila clam, Ruditapes philippinarum, is one of the most economically important marine bivalves in the west coast of Korea, profitability of the clam business has reduced recently because of a shortage of seed clam supply. Thus, this study intended to secure wild spats in clam beds by developing suitable substrates for a spat collector on which Manila clam spats adhere. For this, 10 substrates were individually placed into 2 L onion bags and were deployed in Hajeon clam bed and Gomso port, in Gomso Bay on the west coast of Korea. The spat collectors were designed to suspend in water by buoys during high tide. About 3 months later, Manila clam and other bivalve spats were identified and counted by morphological and molecular diagnoses. The number of Manila clam spats on each substrate varied from 12 to 153 and 17 to 728 in Gomso port and Hajeon clam bed, respectively. The highest number of manila clam spats were collected on a sun shade mesh sheet. The size and total weight of the Manila clam spat averaged at 2 mm and 5 mg, respectively. Our study showed that the sun shade mesh sheet is the most efficient substrate for Manila clam spat collection, but a nursery growing technique after spat collection is needed to develop for the use of the spats for grow out because spats collected are not sufficient size in the region.