Effects on the Growth and Survival of Eggs and Embryos of the California Grunion (Leuresthes tenuis) Exposed to Trace Levels of Tributyltin.

This experiment was conducted to determine the effects of various dose levels of tributyltin (TBT) on the eggs, embryos, and larvae of the California grunion (Leuresthes tenuis). Both pre- and postfertilization effects were examined. The study demonstrated that the presence, during embryonic development, of tributyltin cation derived from antifouling coating leachates at concentrations from 0.14 to 1.72 micrograms TBT/L had no adverse effects on either the hatch success or growth of embryonic fish. Continuous exposure to water concentrations of TBT at and below 1.72 micrograms/L) had no adverse effects on embryonic development and, in fact, significantly enhanced hatch success and stimulated growth suggesting a hormestic effect. Exposure of hatched larvae to similar concentrations of TBT for 7 days did not significantly affect survival. High dosing of TBT (74 micrograms/L) during fertilizing fertilization, representing possible chemically available interstitial concentrations, reduced hatching success by about 50 percent over controls. Similar dosing at 10 micrograms/L showed no significant reduction in hatching success.