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dc.contributor.authorLaRoche, Nicole
dc.date.accessioned2021-11-04T23:04:52Z
dc.date.available2021-11-04T23:04:52Z
dc.date.issued2020-12
dc.identifier.urihttp://hdl.handle.net/11122/12412
dc.descriptionThesis (M.S.) University of Alaska Fairbanks, 2020en_US
dc.description.abstractUntil translocation efforts in the 1960s, sea otters (Enhydra lutris) were absent from Southeast Alaska due to extirpation by the fur trade in the 18th and 19th centuries. About 400 sea otters were reintroduced to six Southeast Alaska locations, including two sites near Prince of Wales Island in southern Southeast Alaska. The most recent US Fish and Wildlife Service population count, completed in 2012, estimated that about 25,000 sea otters inhabited Southeast Alaska. Sea otters will reduce invertebrate prey biomass when recolonizing an area. By quantifying sea otter diets and caloric intake according to recolonization patterns, we can better understand the ecosystem impacts of sea otter population increase and range expansion. The goal of this study was to quantify changes in seasonal diet composition and assess the energetic quality of sea otter prey in southern Southeast Alaska. I made visual foraging observations of 3,385 sea otter dives around Prince of Wales Island (POW) to determine diet composition during the spring and summer months. I then collected vibrissae from 45 sea otters obtained from subsistence hunters to assess year-round sea otter diets using stable isotopes. I collected sea otter prey items throughout POW in three seasons (May 2018, August 2018, and February 2019) to measure energy, lipid and protein content, and delta¹³C (carbon) and delta¹⁵N (nitrogen) values. Sea otter diets mainly consisted of clams, as quantified both from visual observations and stable isotope analysis. However, there was more variation in the diet estimates from stable isotope analysis. Stable isotope analysis revealed variation among individual diets of sea otters and individuality in diet within the POW region of sea otters. Sea otters seasonally increased consumption of some prey when the prey was highest in lipid and overall caloric content. Sea otters switched prey types when the prey was more energetically valuable. The results of this study will aid in future management of shellfisheries, subsistence hunting, and implementing co-management of a protected species by providing quantitative diet composition data for stakeholders. This work is a part of a large-scale project examining how the recovery of sea otters structures nearshore marine ecosystems, provides ecosystem services, and affects community sustainability.en_US
dc.description.sponsorshipNational Science Foundation (NSF) Coastal SEES (Science, Engineering and Education for Sustainability), NSF Bio-Oce (Biological Oceanography), EarthWatch Institute, University of Alaska Fairbanks Biomedical Learning and Student Training, Cooperative Institute of Alaska Research (CIFAR), and National Oceanic and Atmospheric Administration (NOAA) Auke Bay Laboratoriesen_US
dc.description.tableofcontentsGeneral introduction -- Chapter 1: Behavioral observations and stable isotopes reveal high individual variation and little seasonal variation in sea otter diets in Southeast Alaska -- Chapter 2: Sea otter diet nutrient composition with respect to recolonization, life history, and season in southern Southeast Alaska -- General conclusion -- Appendix.en_US
dc.language.isoen_USen_US
dc.subjectSea otteren_US
dc.subjectSea otter dieten_US
dc.subjectSea otter behavioren_US
dc.subjectSoutheast Alaskaen_US
dc.subject.otherMaster of Science in Fisheriesen_US
dc.titleSea otter diet composition with respect to recolonization, life history, and season in southern Southeast Alaskaen_US
dc.typeThesisen_US
dc.type.degreemsen_US
dc.identifier.departmentDepartment of Fisheriesen_US
dc.contributor.chairPearson, Heidi C.
dc.contributor.committeeEckert, Ginny L.
dc.contributor.committeeMiller, Todd
refterms.dateFOA2021-11-04T23:04:52Z


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