HISTOPATHOLOGY IN WINTER FLOUNDER (PLEURONECTES-AMERICANUS) LIVING ADJACENT TO A PULP AND PAPER-MILL

Winter flounder were captured by scuba divers from an area adjacent to a sulfite pulp and paper mill and from a reference site and the tissues examined for lesions. Severe hyperplasia of the gills, focal vacuolation in the liver, and multifocal hemosiderosis in the spleen and liver were most pronounced in large, adult fish collected near the mill. Lesions were less severe and prevalent in smaller fish. Vacuolation in the liver represents a preneoplastic lesion. The histopathological changes appear to be the result of chronic exposure. Few or no lesions were observed in the tissues of flounder taken from the reference site. Although the specific cause of these lesions is unknown, it is likely associated with cytotoxic compounds.