s ublethal effects of t ributyltin and t ri Phenyltin on l arvae of t hree sP ecies of abalone from j aPan

Acute toxicity tests were conducted to determine the effects of low, environmentally realistic, concentrations of tributyltin (TBT) and triphenyltin (TPhT) on early life stages of four commercially important fisheries and aquaculture species from Japan: the abalone Haliotis madaka, H. gigantea and H. discus discus, and the topshell Turbo (Batillus) cornutus. The toxicity endpoint was abnormal larval shell development after 24 and 48 h. Nominal values were confirmed by gas chromatography analysis. The 24-h median effective concentration (EC50) values for TBT were between 0.18 and 1.89 µg L -1 , depending on the species; for TPhT the 24-h EC50 for H. madaka was 0.33 µg L -1 . The TBT 48-h EC50 values were between 0.16 and 0.56 µg L -1 for H. discus discus and H. madaka, and for TPhT about 0.19 µg L -1 for H. madaka. The 24-h EC10 values for all species were about 0.04 µg L -1 , for both organotin compounds, and the 48-h EC10 values were between 0.03 and 0.15 µg L -1 . Environmental concentrations of TBT of 0.02 to 0.16 µg L -1 have recently been detected near marinas and ports in Japan, and similar concentrations can be found in other countries in Asia and elsewhere. Thus, concentrations of TBT remain high enough in many areas to inhibit development and settlement of abalone larvae, and therefore recruitment rates, potentially affecting abalone fisheries and re-stocking efforts. The effects of experimental conditions and different endpoints are also discussed.