Contaminant Monitoring for NMFS Marine Mammal Health and Stranding Response Program

by Usha Varanasi, Environmental Conservation Div, Seattle, United States,
John E. Stein, Environmental Conservation Div, Seattle, United States,
Karen L. Tilbury, Environmental Conservation Div, Seattle, United States,
Donald W. Brown, Environmental Conservation Div, Seattle, United States,
James P. Meador, Environmental Conservation Div, Seattle, United States,
Margaret M. Krahn, Environmental Conservation Div, Seattle, United States,
Sin-Lam Chan, Environmental Conservation Div, Seattle, United States,



Document Type: Proceeding Paper

Part of: Coastal Zone '93

Abstract: Because of increasing concern that chemical contamination may impair the health of marine mammals, a better understanding of the extent of contamination and types of toxic effects in these ecologically important animals is needed. The National Marine Fisheries Service has initiated a broadly based and systematic study of several species of marine mammals to better define the environmental hazards encountered by these species. To date, samples from a number of species including harbor seals (Phoca vitulina), Northern fur seals (Callorhinus ursinus), Steller sea lions (Eumetopias jubatus) and bowhead whales (Balaena mysticetus) from Alaska; harbor seal, harbor porpoises (Phocoena phocoena), minke whale (Balaenoptera acutorostrata) and gray whales (Eschrichtius robustus) from the Pacific coast; bottlenose dolphins (Tursiops truncatus) from the Gulf of Mexico; and pilot whales (Globicephala malaena) and harbor porpoises from the Northeast coast of the USA have been analyzed for a board spectrum of chemical contaminants including trace and essential elements, chlorinated hydrocarbons, aromatic hydrocarbons and their metabolites. Although for most species the number of samples available is limited at present, the database has begun to yield useful information. For example, contrary to popular belief, gray whales that strand in urban areas of Puget Sound have much lower levels of toxic contaminants in their tissues than do Steller sea lions sampled from environmentally pristine areas in Alaska. These findings demonstrate that caution is needed before drawing any conclusions about the cause of stranding from the level of contamination at a stranding site. The results from pilot whales also showed evidence for maternal transport of organic contaminants and toxic elements to the fetus and accumulation of certain toxic elements (e.g., mercury, lead) in fetal brain tissue. Thus, the impact of pollution on the early life stages of marine mammals, especially those species at the top of the food chain, is being explored.

Subject Headings: Pollution | Pollutants | Hydrocarbons | Toxicity | Ports and harbors | Environmental issues | North America | United States | Alaska | Gulf of Mexico

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