Blood Chemistries and Body Condition of Steller Sea Lion Pups at Marmot Island, Alaska
Abstract
This work is part of a large project focused on assessing the blood chemistry and body condition of pinnipeds in and around Alaskan waters. We have utilized a series of blood indices that reflect hydration state, blood oxygen transport, and protein, lipid and carbohydrate metabolism. In addition to total mass, animals are also examined for blubber thickness at several locations around the body These parameters are useful for detecting significant changes in health status that might alter water balance, cause anemia, or compromise basic metabolic status. The Steller sea lion (Eumetopias jubatus) is of particular interest because its population has declined over the last 20 years to such an extent that the species has been designated as threatened under the United States Endangered Species Act (Federal Register, November 26, 1990). The cause(s) of the decline are unknown but may be linked to redistribution, disease, environmental perturbations (which may influence the quality or quantity of prey), the synergistic effects of fisheries, or other unknown causes (Braham et al. 1980, Merrick et al. 1987, Loughlin and Merrick 1989, Loughlin et al. 1992). Calkins and Goodwin (1988) suggested that adult female Steller sea lions in the Gulf of Alaska during 1985-1986 were anemic and smaller in body size than animals sampled ten years earlier, possibly as a result of food limitations. Also, Castellini and Calkins (1993) have shown the latter group was more lean than the animals studied in the 1970s. The best population models currently suggest that the decline in sea lion numbers results from a reduction in survival of juveniles or breeding females, or both (York, personal communication).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1993
- Accession Number
- ADA268664
Entities
People
- M. A. Castellini
- R. W. Davis
- T. R. Loughlin
- Terrie M. Williams
Organizations
- Naval Command, Control and Ocean Surveillance Center