HEAVY-METAL ACCUMULATIONS AND THEIR RECENT CHANGES IN SOUTHERN MINKE WHALES BALAENOPTERA-ACUTOROSTRATA

The concentrations of heavy metals in the livers of southern minke whales, B. acutorostrata, were determined by atomic absorption spectrophotometry, and their accumulation levels and variations were compared to food habit, and biological parameters. The concentration levels and bioconcentration factors of metals in the minke whale were relatively high for Fe and Cd and low for Hg, when compared to seals and small-toothed cetaceans from different waters. For most of the metals examined, the concentrations were log-normally distributed. The concentrations of Fe, Cd, and Hg were positively correlated with age, but a correlation was not observed for the other metals. While the hepatic Fe concentration linearly increased with age, the concentrations of Cd and Hg increased up to the age of about 20 years and thereafter decreased year by year. Such unusual age trends of Cd and Hg are considered to be due to recent changes of the amount of food intake by the minke whale, as a result of structural disturbances in the Antarctic marine ecosystem due to commercial whaling. Also, the hepatic concentrations of metals varied between sexes, and with reproductive status of the matured female; the concentration of Fe was lower in the females than the males, and Fe, Pb, Ni, and Co concentrations in the matured females decreased with progress of gestation. © 1987 Springer-Verlag New York Inc.