Disease and gill lesions in yellow perch (Perca flavescens) exposed to oilsands mining-associated waters

Adult yellow perch were stocked into experimental ponds designed to test th e biological effects of aquatic reclamation alternatives currently being pu rsued bg the oil sands mining industry, Water-quality characteristics of oi l sands-influenced water in the experimental ponds included increased salin ity and elevated trace organics associated with ran, oil sands (bitumen), A fter 3 and 10 months of exposure to affected waters, perch gross pathologie s including severe fin erosion and virally induced tumors were observed in exposed individuals. Gill histopathology revealed large aneurysms accompani ed by a proliferation of chloride and epithelial cells in the interlamellar spaces. Gill pathologies were not paralleled by a decrease in plasma sodiu m, calcium, or chloride. The frequencies of gross pathologies and gill chan ges were correlated to the concentrations of the oil sands-related compound s. As inorganic and organic compounds associated dth oil sands activities a re highly intercorrelated, and the observed lesions and changes are not dia gnostic of particular toxicants, it was not possible to isolate the causati ve chemical factor(s) responsible. The incidence of observed lesions and gi ll pathologies could not be conclusively linked to increased mortality rate s observed in the exposed populations. Evidence of recovery in the patholog ies nas observed between 3 and 10 months of exposure, coincident with a sta bilization in population numbers. (C) 2000 Academic Press.