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Brenda E. Ballachey

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Sea otters in western Prince William Sound (WPWS) and elsewhere in the Gulf of Alaska suffered widespread mortality as a result of oiling following the 1989 T/V Exxon Valdez oil spill. Following the spill, extensive efforts have been directed toward identifying and understanding long-term consequences of the spill and the process of recovery. We conducted annual aerial surveys of sea otter abundance from 1993 to 2009 (except for 2001 and 2006) in WPWS. We observed an increasing trend in population abundance at the scale of WPWS through 2000 at an average annual rate of 4 percent: however, at northern Knight Island where oiling was heaviest and sea otter mortality highest, no increase in abundance was evident by...
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Exposure to contaminants other than petroleum hydrocarbons could confound interpretation of Exxon Valdez oil spill effects on biota at Prince William Sound, Alaska. Hence, we investigated polychlorinated biphenyls (PCBs) in blood of sea otters and harlequin ducks sampled during 1998. PCB concentrations characterized by lower chlorinated congeners were highest in sea otters from the unoiled area, whereas concentrations were similar among harlequin ducks from the oiled and unoiled area. Blood enzymes often elevated by xenobiotics were not related to PCB concentrations in sea otters. Only sea otters from the unoiled area had estimated risk from PCBs, and PCB composition or concentrations did not correspond to reported...
Categories: Publication; Types: Citation; Tags: Marine Pollution Bulletin
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Three experiments were conducted to investigate the genotoxic effects of crude oil on mink and sea otters, In the first experiment, the effects on mink of chronic exposure to weathered Prudhoe Bay crude oil were studied, Female mink were fed a diet that included weathered crude oil for a period of 3 weeks prior to mating, during pregnancy and until weaning. Kits were exposed through lactation and by diet after weaning until 4 months of age. Kidney and liver tissues of the kits were examined using flow cytometry (FCM) and it was found that the genome size was increased in kidney samples from the experimental group compared to the control group. This effect was probably due to some type of DNA amplification and it...
Categories: Publication; Types: Citation; Tags: Ecotoxicology
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Similar to other species that in recent centuries experienced unregulated human exploitation, sea otters were extirpated throughout large portions of their historic range in the North Pacific. For most of the twentieth century, with cessation of the fur trade and because of concerted efforts at conservation, sea otters recovered much of their historic range and abundance. Late in the twentieth century, increased predation by killer whales in southwest Alaska drove sea otter populations to a few percentage points of their prior abundance, and one of the nation’s largest oil spills in south-central Alaska caused the death of several thousand animals and required more than two decades for recovery. In California, entanglement...
Categories: Publication; Types: Citation
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Since 1999, vessel based surveys to estimate species composition, distribution and relative abundance of marine birds and mammals have been conducted along coastal and pelagic (offshore) transects in Glacier Bay, Alaska. Surveys have been conducted during winter (November-March) and summer (June). This annual report presents the results of those surveys conducted in March and June of 2001. Following completion of surveys in 2002 we will provide a final report of the results of all surveys conducted between 1999 and 2002.Glacier Bay supports diverse and abundant assemblages of marine birds and mammals. In 2001 we identified 58 species of bird, 7 species of marine mammal, and 6 species of terrestrial mammal on transects...
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