TP10 Migrations: Role of Biota in Contaminant Distribution
D135-136
1:20 PM - 4:40 PM, Tuesday
() Productivity, diets, and environmental contaminants in nesting bald eagles from the Aleutian Archipelago, Alaska.
Anthony, R1, Ricca, M2, Miles, A2, 1 Oregon Cooperative Fisheries and Wildlife Research Unit, U.S. Geological Survey, Corvallis, OR, USA2 U.S. Geological Survey, Western Ecological Research Center, Davis, CA, USA
ABSTRACT- We studied productivity, diets, and environmental contaminants in nesting bald eagles in the Aleutian Islands, Alaska, during 1993-94 and 2000-02. Productivity on Adak, Tanaga, Amchitka, and Kiska Islands ranged from 0.65 to 1.70 young produced per occupied breeding territory. Productivity was higher at all islands during 2000-20 as compared to 1993-94. Lowest productivity (0.67 yg/ occupied site) occurred at Kiska Island in 1993-94 and was associated with elevated levels of DDE, mercury, and other organochlorine pesticides in unhatched eagle eggs. In contrast, PCB concentrations were higher in eggs from areas of military activities at Adak and Amchitka Islands but appeared unrelated to productivity. The most likely source of these contaminants in bald eagles was from their diets, which were variable both temporally and spatially. We hypothesize that the high proportion of seabirds in eagle diets might be the source of organochlorine and mercury contamination. Over the two time periods, there was a decline in the proportion of fish and mammals in eagle diets with a corresponding increase in avian prey. This temporal change in diets was likely due to the 90% decline in sea otter numbers and corresponding collapse of the kelp forest ecosystem during the two time periods. Our results identify potential sources and transport mechanisms for these contaminants to the Aleutian Islands.
Key words: mercury, organochlorine pollutants, bald eagles, Aleutian Archipelago