Mercury Pollution and the Saimaa Ringed Seal (Phoca hispida saimensis)

摘要

Mercury concentrations in the hair and various tissues of the Saimaa ringed seal were monitored from 1980 to 1995. In the liver, muscle and kidney of weaned pups mercury concentrations dropped in the middle of the 1980s. In the natal hair and liver of young pups, however, no clear decrease was seen. In the natal hair and main fish prey species of the seals mercury concentration were highest in areas of humic water. Mercury concentration in the liver of adults has not changed significantly since 1981. Age of the seal is clearly correlated with mercury concentration in the liver. Shortage of selenium is assumed to be one reason for high concentrations of mercury in muscle. The mercury concentration in hair decreased markedly in an adult seal in captivity, after giving selenium. Based on these findings, one reason for the decrease in population density of the Saimaa seal in this century may have been mercury pollution.