Histopathology of adult pacific herring in Prince William Sound, Alaska, after the Exxon Valdez oil spill

Pacific herring (Clupea pallasi) sampled from oiled sites in Prince William Sound, Alaska, U.S.A., 3 weeks after the 1989 Exxon Valdez oil spill had m ultifocal hepatic necrosis and significantly increased tissue concentration s of polynuclear aromatic hydrocarbons (PAH). By comparison, Pacific herrin g from reference sites in 1989 and from all sites in 1990 and 1991 did not have hepatic necrosis or increased PAH concentrations. Adult Pacific herrin g were sampled for histopathology of liver, spleen, and kidney from oiled a nd reference sites in April (1989 and 1991) and October (1990 and 1991). In creased scores for macrophage aggregates contributed to significant differe nces in 1990, but these differences probably resulted from sampling older f ish from the oiled site. Naphthalenes were the predominant PAH in all tissu e samples. The development of hepatic necrosis and the predominance of naph thalenes in samples from 1989 is consistent with recent laboratory study in which crude oil exposure resulted in dose-dependent expression of viral he morrhagic septicemia virus (VHSV). We conclude that Pacific herring were ex posed to Exxon Valdez oil in 1989 and that development of hepatic necrosis in exposed fish probably was a result of VHSV expression.