Effect of maternal exposure to tributyltin on reproduction of the pearl oyster (Pinctada fucata martensii)

We examined the effect of tributyltin (TBT) on reproduction of the pearl oyster (Pinctadafucata martensii). In a maternal exposure test, five female pearl oysters were exposed to TBT at measured concentrations of 0 (control), 0.092, or 0.191 μg/L at 25°C for one week, and the embryo developmental success (the ratio of normal D-larvae to all larvae) was measured. The embryo developmental success was significantly decreased in the 0.191-μg/L treatment group (65.5%) compared to that in the control group (82.5%; p = 0.031). Concentrations of TBT in the ovary reached 0.088 μg/g in the 0.191-μg/L treatment group. In a waterborne exposure test, inseminated eggs were exposed to TBT at measured concentrations of 0 (control), 0.020, 0.045, 0.091, 0.192, or 0.374 μg/L for 24 h. The embryo developmental success also was significantly decreased in the 0.192-μg/L treatment group (78.3%; p = 0.020) and no development at all was observed in the 0.374-μg/L treatment group compared with that in the control group (95.4%). These results clearly demonstrate that TBT accumulating in the bodies of bivalves has the potential to inhibit reproduction.