The effect of cytochalasin B dosage on the survival and ploidy of Crassostrea virginica (gmelin) larvae

Survival and ploidy of D-stage oyster larvae (Crassostrea virginica) were d etermined following the rearing of embryos exposed to CB dosages of 0.5 mg/ L, 0.25 mg/L, and 0.125 mg/L for 10 minutes, with 0.05% DMSO and ambient se awater as controls. The experiment was replicated three times on the same d ay with the same procedures and partially stripping the same male oysters; different females were used for each replicate. CB dosage treatments began when 50% of the eggs reached PBI (24-31 min). Embryos were reared for 48 h at ambient temperature and salinity. Resulting triploid percentages were 13 % +/- 6.7% (0.125 mgCB/L), 61.8% +/- 6.2% (0.75 mgCB/L). and 68.2% +/- 14.1 % (0.5 mgCB/L). No significant difference (P less than or equal to 0.05) in mean survival was found between the three CB treatments. Significant diffe rences in mean survival between the three replicates implies variability be cause of different sources of eggs.