Levels of Mercury in Wild Mink (Mustela vison) and River Otter (Lutra canadensis) from Ontario and Nova Scotia: relation to age and parasitism

摘要

In order to assess the levels of Hg present in populations of mink and otter, animals were collected from Ontario and Nova Scotia, Canada, by registered trappers. Necropsies were performed on all collected individuals; body condition, age, sex, weight, reproductive status and evidence of parasitism were noted. For both species, Hg levels were highest in the Nova Scotia populations. Nova Scotia mink concentrations were as high as 78 ppm in the fur, while otter fur concentrations reached 89 ppm. Ontario values were as high as 21 ppm and 15 ppm for mink and otter, respectively. Total Hg in the fur was strongly correlated with levels in the brain (r = 0.921) and liver (r = 0.916) for mink and also for otter (r = 0.902 fur vs. brain; r = 0.784 fur vs. liver), indicating that fur is a suitable monitoring tissue. For mink and otter collected from Ontario, the average concentration of Hg in the three tissues did not differ with respect to age nor were there significant correlations between age and the level of Hg in the tissues. The correlation between parasitism and increased Hg levels in mink is significant in Nova Scotia.