HISTOPATHOLOGY AND CYTOGENETIC EVALUATION OF PACIFIC HERRING LARVAE EXPOSED TO PETROLEUM-HYDROCARBONS IN THE LABORATORY OR IN PRINCE-WILLIAM-SOUND, ALASKA, AFTER THE EXXON-VALDEZ OIL-SPILL

Following the 1989 Exxon Valdez oil spill in Prince William Sound, Ala ska, USA, Pacific herring (Clupea pallasi) larvae sampled from oiled s ites had ascites, pericardial edema, and genotoxic damage. Laboratory study confirmed that these lesions were consistent with oil exposure. Pacific herring larvae were trawled from two oiled and two unoiled sit es in Prince William Sound in May 1989. Larvae from oiled sites were s horter, had ingested less food, had slower growth (oiled, 0.07-0.10 mm /day; unoiled, 0.15-0.18 mm/day), and had higher prevalence of cytogen etic damage (oiled, 56-84%; unoiled, 32-40%) and ascites (oiled, 16%; unoiled, 1%) than from unoiled sites. In the laboratory experiment Pac ific herring eggs were exposed to an oil-water dispersion of Prudhoe B ay crude oil (initial concentrations of 0.0, 0.10, 0.24, 0.48, and 2.4 1 mg/L) and sampled for histopathology <24 h after hatching. Effects w ere significant at the 0.48 mg/L dose (Dunnett's procedure, P < 0.05). Lesions included ascites; hepatocellular vacuolar change and degenera tion or necrosis of skeletal myocytes, retinal cells, and developing b rain cells. Lesions in field-sampled larvae were consistent with highe r mortality rates documented in lan ae from oiled sites.