Oil exposure and effects in subtidal fish following the Exxon Valdez oil spill

Abstract

The assessment of oil exposure and resulting biological effects in subtidal fish following marine oil spills is a rather challenging task, due to difficulty in sampling and a lack of methodologies that allow direct determination of petroleum exposure. - Because fish can rapidly metabolize petroleum hydrocarbons, standard chemical analyses are of little use for assessing exposure of fish to oil. However, methods are now available for measuring the metabolites of petroleum hydrocarbons in fish, as described elsewhere by Krahn and her colleagues. There have also been advances in determining early biochemical effects-such as induction of the cytochrome P450 system-and more severe biological effects-such as histopathological alterations and reproductive dysfunction in fish species following exposure to petroleum hydrocarbons and related compounds. Accordingly, following the Exxon Valdez oil spill, we have been using these approaches and methodologies to measure oil exposure in subtidal fish species, together with associated biological effects. These studies have been conducted at sites inside Prince William Sound and along the Kenai and Alaska Peninsulas. Our results show a continuing exposure of several fish species, including benthic species, which indicates petroleum contamination of subtidal areas. We have also assessed reproductive function and histopathological alterations in several of these species; and while major effects have not been documented, some suggestion of histopathological alterations of gill exists in one species of benthic fish. Still to be determined are the potential impacts on fishery resources of long-term exposure to petroleum, albeit at moderate to low levels.