ABSTRACT
Sublethal and reproductive effects of methylmercury in freshwater fish have been observed at environmentally relevant exposure levels in a number of recent field and laboratory studies. The consequences of methylmercury exposure may be more severe for wild fish than for fish in laboratory tests in which fish are provided ample food. WA Paul Drevnick et al. proposed that methylmercury induces apoptosis in steroidogenic cells in the gonads of fish. They observed an increase in the number of apoptotic follicular cells in the gonads of female fathead minnows that had impaired reproduction due to chronic methylmercury exposure. Laboratory and field studies have shown that methylmercury exposure causes oxidative stress in fish tissues through the formation of radical oxygen species and lipid peroxidation. Species differences in sensitivity to methylmercury exposure in fishes have not been assessed, but may be considerable given the variation in avian sensitivity reported by Germany Gary H. Heinz et al.
