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 determined 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 seawater as controls. The experiment was replicated three times on the same day 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% plus or minus 6.7% (0.125 mgCB/L), 61.8% plus or minus 6.2% (0.25 mgCB/L), and 68.2% plus or minus 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 differences in mean survival between the three replicates implies variability because of different sources of eggs.