FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

Oyster matured all year round in the southern part of Taiwan. Adults with matured gonad were selected and sexed and then gametes were scraped. Then eggs and sperms were mixed together in proper concentration. Fertilized eggs were washed several times to remove excess sperms. Embryos were set without aeration till hatched. D-larvae were reared with Tetraselmis and Isochrysis in half-ton fiberglass tanks. Larvae reached to 300-350 μm within 15 days under controlled temperature and salinity at 28℃ and 25-30 ppt, respectively. At this time, eye spot and foot developed and larval was ready to settle. Treated with epinephrine (0.1 mM) for one hour, some of eyed larvae metamorphosed without settlement and became clutchless oyster. Clutchless oyster grew from 0.2 to 20 gram in 20 weeks in the drainage of shrimp ponds.
Key words: Oysters, Larval rearing, Clutchless