Macronutrient composition of sea otter diet with respect to recolonization, life history, and season in southern Southeast Alaska
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Published:2023-05
Issue:5
Volume:13
Page:
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ISSN:2045-7758
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Container-title:Ecology and Evolution
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language:en
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Short-container-title:Ecology and Evolution
Author:
LaRoche Nicole L.1ORCID,
King Sydney L.2ORCID,
Fergusson Emily A.3,
Eckert Ginny L.1ORCID,
Pearson Heidi C.12ORCID
Affiliation:
1. College of Fisheries and Ocean Sciences University of Alaska Fairbanks Juneau Alaska USA
2. Department of Natural Sciences University of Alaska Southeast Juneau Alaska USA
3. NOAA National Marine Fisheries Service Alaska Fisheries Science Center, Auke Bay Laboratories Juneau Alaska USA
Abstract
AbstractThe 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 energy 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, and winter) to measure caloric value and lipid and protein content. We observed 3523 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 energetic intake rates (EIR, kcal/min), and prey had higher energy content (kcal/g). Females with pups had the highest diet diversity and the lowest EIR. Sea otter EIR 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.
Funder
National Institute for Health Research
National Oceanic and Atmospheric Administration
National Science Foundation
Subject
Nature and Landscape Conservation,Ecology,Ecology, Evolution, Behavior and Systematics
Cited by
1 articles.
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