PACIFIC HERRING (CLUPEA-PALLASI) EMBRYO SENSITIVITY TO PRUDHOE BAY PETROLEUM-HYDROCARBONS - LABORATORY EVALUATION AND IN-SITU EXPOSURE AT OILED AND UNOILED SITES IN PRINCE-WILLIAM SOUND

Pacific herring (Clupea pallasi) embryos were exposed to oil-water dis persions of Prudhoe Bay crude oil in artificial seawater. The original extract contained 9.67 mg/L high molecular weight and 64 mg/L low mol ecular weight hydrocarbons. From this stock, concentrations of oil-wat er dispersions were made ranging from 9.67 to 0.01 mg/L. Pilot studies demonstrated that over 85% of the low molecular weight hydrocarbons e vaporated during the first 24 h of each exposure. Seawater with and wi thout oil-water dispersions showed constant values of 10.2-10.4 mg O-2 /L, a pH of 8.4, and salinity of 29.7-30.3 parts per thousand. Genetic damage was the most sensitive biomarker for oil exposure, followed by physical deformities, reduced mitotic activity, lower hatch weight, a nd premature hatching. Oil had its greatest effect on the blastodisc a nd gastrula stages. Embryos deployed in Prince William Sound 3 years a fter the Exxon Valdez oil spill yielded a greater proportion of abnorm al (p < 0.002) and lower weight (p < 0.01) larvae at previously oiled sites than at unoiled sites. Although there is no unequivocal evidence that oiled sites pose a long-term hazard to herring embryo or larval survival, a more comprehensive in situ study is warranted in light of the data obtained during this study.