LARGE-SCALE PRODUCTION OF TRIPLOID OYSTERS, CRASSOSTREA-VIRGINICA (GMELIN), USING STRIPPED GAMETES

Successful production of triploid oysters requires precise control of the timing of fertilization of eggs. Logistically, using stripped gametes is the most practical method for producing triploids because the time of fertilization can be easily controlled. We examined several factors that may affect the survival and yield of triploid C virginica from stripped gametes in large scale spawnings. Triploidy was induced by inhibiting polar body II with cytochalasin B. Fourteen replicates containing from 17 to 49 million (M) eggs were treated. Survival and percent triploidy of 48-h-old larvae were not correlated; mean survival was 22% and mean triploidy was 79%. About 72% of 138 spat examined were triploid, indicating that the estimate of triploidy at 48 h was accurate. Overall, 400.8 M eggs yielded about 17.8 triploid spat, an efficiency of 4.4%. All linear regression models incorporating the treatment variables were non-significant. Variability may be random, a reflection of egg quality, or both.