Age dependent and geographical variations of heavy metals in northern fur seals
- Ehime Univ., Matsuyama (Japan)
- National Marine Mammal Lab., Seattle, WA (United States)
- National Research Inst. of Far Seas Fisheries, Shimizu (Japan)
The concentrations of Fe, Mn, Zn, Cu, Cd and Hg were determined in muscle, liver and kidney of 7 northern fur seal (Callorhinus ursinus) collected off Sanriku, Japan and from the Pribilof Islands, Alaska. Age trends, regional differences, and the possible discrimination of populations using heavy metals as tracers are also discussed. Almost all the elements except for Cd were found to be higher in liver. Cadmium levels in kidney were found to be higher than other organs. In muscle, concentrations of Hg, Cd and Fe were found to increase significantly with age. Manganese concentrations decreased with age in muscle and kidney. In kidney Cu concentration decreased with age. Cadmium concentrations of the northern fur seals in this study were higher than other otariids, reflecting a predominantly squid diet. Concentrations of Mn and Hg were found to be higher in the fur seals caught off Sanriku than in animals from the Pribilof Islands, while those of Zn and Cd were found to be higher in the samples from the Islands. The difference in concentration levels of Cd and Hg can be attributed to the sea water concentration, whereas differences in essential elements like Fe, Mn, Zn and Cu could be associated with seasonal physiological changes. Discriminant analysis of heavy metal concentrations was used to identify habitat. Sixty-three of 67 animals (94%) can distinctly be classified using this technique. Heavy metal concentrations in tissues may provide a useful information to elucidate the primary feeding grounds of fur seals.
- OSTI ID:
- 367524
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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