Diet composition and fate of contaminants in subsistence harvested northern sea otters (Enhydra lutris kenyoni) from Icy Strait, Alaska

• Main Author: Brown, Kristin Lynn
• Other Authors: Atkinson, Shannon, Andrews, Russel, Pearson, Heidi
• Format: Thesis
• Language: English
• Published: 2020
• Subjects: sea otter; Alaska; Icy Strait; heavy metals; diet; cadmium; selenium; lead; mercury; arsenic; health; hygiene; Fairbanks; Glacier Bay; glacier; Modiolus modiolus
• Online Access: http://hdl.handle.net/11122/11259

Thesis (M.S.) University of Alaska Fairbanks, 2020 Northern sea otters (Enhydra lutris kenyoni) in Southeast Alaska have experienced a significant population increase since their successful reintroduction to the area after previous near extirpation owing to historic fur trading. The purpose of this study was to examine sea otter diet and metals contamination in an area of Southeast Alaska with the most robust increases in sea otter numbers, Glacier Bay/Icy Strait, with the intent of gathering baseline data for a healthy population of sea otters and as a reflection of the local coastal environmental health of the area. This research was a collaborative effort with Alaska Native subsistence hunters and the Alaska Department of Environmental Conservation. In Chapter 1, sea otter stomachs (n=25) were obtained in April 2015 and April 2016 from Alaska Native subsistence hunters in Icy Strait, Alaska. There were no differences in sea otter diet between years. Bivalves dominated the sea otter diet. Northern horsemussels (Modiolus modiolus) made up the greatest proportion of the diet (0.46 ± 0.48). Fat gaper clams (Tresus capax) and northern horsemussels were found in the highest proportion of stomachs (0.64 and 0.60, respectively). There was not an apparent trend between sea otter age and the minimum number of total prey items, stomach contents mass, or mean frequency of occurrence of the top four prey species. Sea otters from this study are likely to be dietary generalists throughout their lives. In Chapter 2, brain, gonad, kidney, and liver tissues, as well as stomach contents were analyzed for arsenic, cadmium, copper, lead, total mercury, and selenium for the 2015-harvested sea otters that were also referenced in Chapter 1 (n=14). In general, arsenic and lead had the highest concentrations in stomach contents, cadmium and selenium were highest in the kidneys, and copper and total mercury were highest in the livers. While brains and gonads had the lowest metals concentrations of any tissue, the metal with the ...