In Alaska's Prince William Sound, site of the 1989 Exxon Valdez oil spill, Pacific herring are suffering a major epidemic. The outbreak has cost commercial fisheries nearly $10 million annually and is devastating a community that depends on its fishing industry. Pathologist Gary Marty, of the UC Davis School of Veterinary Medicine, is examining what is causing literally tons of Pacific herring to be deformed by ulcers and other lesions. Marty and a team of virologists and fisheries biologists are the first to study the causes of herring sickness and mortality in this wild habitat. The group is conducting parallel population research at a reference site, Sitka Sound, where herring fisheries have never experienced an oil spill. According to Marty, a hemorrhagic virus and a chronic herring fungus are the primary causes of the epidemic. The fungus also seemed to afflict 7-year-old fish more than 3-year-old fish. Although many fishermen in the region believe that the Valdez oil spill seven years ago somehow caused the epidemic, Marty says there is not strong evidence to draw such a conclusion. The studies are funded by the settlement paid to the state of Alaska after the spill.