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Sea otter diet nutrient composition with respect to recolonization, life history, and season in southern Southeast Alaska
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  • Nicole LaRoche,
  • Sydney King,
  • Emily Fergusson,
  • Ginny Eckert,
  • Heidi Pearson
Nicole LaRoche
University of Alaska Fairbanks

Corresponding Author:[email protected]

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Sydney King
University of Alaska Southeast
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Emily Fergusson
NOAA Fisheries Auke Bay Laboratories
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Ginny Eckert
University of Alaska Fairbanks
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Heidi Pearson
University of Alaska Southeast
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The sea otter (Enhydra lutris) population of Southeast Alaska has been growing at a higher rate than other regions along the Pacific coast. While good for the recovery of this endangered species, rapid population growth of this apex predator can create a human-wildlife conflict, negatively impacting commercial and subsistence fishing. Previous foraging studies throughout the sea otter range have shown they will reduce invertebrate prey biomass when recolonizing an area. The goal of this study was to examine and quantify the energetic content of sea otter diets through direct foraging observations and prey collection. Our study area, Prince of Wales Island in southern Southeast Alaska, exhibits a gradient of sea otter recolonization, thus providing a natural experiment to test diet change in regions with different recolonization histories. Sea otter prey items were collected in three seasons (spring, summer, winter) to measure caloric value and lipid and protein content. We observed 3,523 sea otter dives during the spring and summer. A majority of the sea otter diet consisted of clams. Sea otters in newly recolonized areas had lower diet diversity, higher kcal/gram intake rates, and higher energetic intake rates. Females with pups had the highest diet diversity and the lowest energetic intake rates (calories per gram consumed). Sea otter energetic intake rates were higher in the fall and winter vs. spring and summer. Sea cucumber energy and lipid content appeared to correspond with times when sea otters consumed the highest proportion of sea cucumbers. These caloric variations are an important component of understanding ecosystem level effects sea otters have in the nearshore environment.
27 Dec 2022Submitted to Ecology and Evolution
28 Dec 2022Submission Checks Completed
28 Dec 2022Assigned to Editor
17 Jan 2023Reviewer(s) Assigned
04 Feb 2023Review(s) Completed, Editorial Evaluation Pending
10 Feb 2023Editorial Decision: Revise Minor
06 Apr 20231st Revision Received
07 Apr 2023Review(s) Completed, Editorial Evaluation Pending
07 Apr 2023Submission Checks Completed
07 Apr 2023Assigned to Editor
11 Apr 2023Editorial Decision: Accept