Distribution, abundance, morphological condition, and cytogenetic abnormalities of larval herring in Prince William Sound, Alaska, following the Exxon Valdez oil spill

Pacific herring (Clupea pallasi) larvae were collected throughout Prince William Sound in May, June, and July following the Exxon Valdez oil spill of March 1989. Movement of herring larvae is related to current patterns within the sound, and deformed larvae were found both inside and outside of areas considered to be oiled. Herring may have been exposed to oil as embryos in contaminated spawning areas and as larvae encountering the oil trajectory. Although it was impossible to estimate the effects of exposure to Exxon Valdez oil, many larvae exhibited symptoms associated with oil exposure in laboratory experiments and other oil spills. These included morphological malformations, genetic damage, and small size. Growth between May and June 1989 was the lowest ever reported for field-caught larval herring. Jaw malformations and genetic damage were highest in May and were elevated through the western area of Prince William Sound, which overlapped the oil trajectory. In June 1989,jaw development was normal, but genetic damage persisted. In contrast, in May 1995, jaw and cytogenetic development were normal and significantly different from those in larvae in 1989.