Mercury levels in tissues of otters from Ontario, Canada: Variation with age, sex, and location

Concentrations of mercury in hair, brain, and liver tissues of river otter (Lutra canadensis) from several townships in Ontario, Canada, were determined. Levels of Hg in these tissues were highly intercorrelated but differed from tissue to tissue. The highest concentration was in hair, followed by liver and brain. The high correlation between Hg in hair and brain, as well as the ease and precision of Hg determinations on hair, demonstrate that Hg in hair holds considerable promise for monitoring the Hg in otters. Within the sampled otters, Hg varied with respect to age. The Hg concentrations increased over the first two to three years of age, remained stable over the next two to three years of age, and then declined in the remaining age‐groups. Mean age of otters in townships with high‐Hg concentrations was about half the mean age of otters in low‐Hg townships. In areas where mercury levels are high, otters may have reduced survivorship because of Hg‐induced stress on their health.