Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska
Dissertation (Ph.D.) University of Alaska Fairbanks, 2020 Sperm whales (Physeter macrocephalus) remove fish from commercial fishing gear in high latitude foraging grounds. This behavior, known as depredation, occurs in the Gulf of Alaska (GOA) sablefish longline fishery and has increased in frequenc...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/11297 2023-05-15T17:59:23+02:00 Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska Wild, Lauren A. Mueter, Franz Straley, Janice Sigler, Michael Witteveen, Briana Andrews, Russ 2020-05 http://hdl.handle.net/11122/11297 en_US eng http://hdl.handle.net/11122/11297 College of Fisheries & Ocean Sciences sperm whale diet Gulf of Alaska Dissertation phd 2020 ftunivalaska 2023-02-23T21:37:40Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2020 Sperm whales (Physeter macrocephalus) remove fish from commercial fishing gear in high latitude foraging grounds. This behavior, known as depredation, occurs in the Gulf of Alaska (GOA) sablefish longline fishery and has increased in frequency and severity since the mid-1990s. Sperm whale foraging ecology and movements in the GOA are poorly understood but are important considerations to how depredation impacts fishery resources and whale behavior. The goals of this dissertation were to use stable isotope analysis to evaluate trophic connections between sperm whales and their prey, estimate the proportional contribution of various prey items to sperm whale diets, and use satellite tag data to evaluate movement and diving behavior of sperm whales in the GOA. Understanding isotopic variability in cetacean skin is important to evaluating dietary information from this tissue; thus, in chapter 1, I first analyzed the stable isotope ratios among layers of cetacean skin to determine how much variability there was within and across layers of cetacean skin. Results showed horizontal layers of cetacean skin to be significantly different isotopically, suggesting evidence of a dietary time series in layers of cetacean skin, where the innermost skin layer represents the most recent diet. These results were used in my second chapter to isolate the most recent diet of sperm whales from the inner layer of skin, and then to estimate proportional contributions of different prey to sperm whale diets. Results showed that the sperm whales sampled prefer sablefish, dogfish, skates, and rockfish, and that the proportional contribution of sablefish to sperm whale diets has increased over the past 15 years as depredation has increased in severity. Chapter three presented an analysis of twenty-nine satellite tags placed on depredating sperm whales in the GOA between 2007 and 2016 to explore movement and diving behavior and how these behaviors may be linked to prey preferences ... Doctoral or Postdoctoral Thesis Physeter macrocephalus Sperm whale Alaska University of Alaska: ScholarWorks@UA Fairbanks Gulf of Alaska |
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Open Polar |
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University of Alaska: ScholarWorks@UA |
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ftunivalaska |
language |
English |
topic |
sperm whale diet Gulf of Alaska |
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sperm whale diet Gulf of Alaska Wild, Lauren A. Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska |
topic_facet |
sperm whale diet Gulf of Alaska |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2020 Sperm whales (Physeter macrocephalus) remove fish from commercial fishing gear in high latitude foraging grounds. This behavior, known as depredation, occurs in the Gulf of Alaska (GOA) sablefish longline fishery and has increased in frequency and severity since the mid-1990s. Sperm whale foraging ecology and movements in the GOA are poorly understood but are important considerations to how depredation impacts fishery resources and whale behavior. The goals of this dissertation were to use stable isotope analysis to evaluate trophic connections between sperm whales and their prey, estimate the proportional contribution of various prey items to sperm whale diets, and use satellite tag data to evaluate movement and diving behavior of sperm whales in the GOA. Understanding isotopic variability in cetacean skin is important to evaluating dietary information from this tissue; thus, in chapter 1, I first analyzed the stable isotope ratios among layers of cetacean skin to determine how much variability there was within and across layers of cetacean skin. Results showed horizontal layers of cetacean skin to be significantly different isotopically, suggesting evidence of a dietary time series in layers of cetacean skin, where the innermost skin layer represents the most recent diet. These results were used in my second chapter to isolate the most recent diet of sperm whales from the inner layer of skin, and then to estimate proportional contributions of different prey to sperm whale diets. Results showed that the sperm whales sampled prefer sablefish, dogfish, skates, and rockfish, and that the proportional contribution of sablefish to sperm whale diets has increased over the past 15 years as depredation has increased in severity. Chapter three presented an analysis of twenty-nine satellite tags placed on depredating sperm whales in the GOA between 2007 and 2016 to explore movement and diving behavior and how these behaviors may be linked to prey preferences ... |
author2 |
Mueter, Franz Straley, Janice Sigler, Michael Witteveen, Briana Andrews, Russ |
format |
Doctoral or Postdoctoral Thesis |
author |
Wild, Lauren A. |
author_facet |
Wild, Lauren A. |
author_sort |
Wild, Lauren A. |
title |
Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska |
title_short |
Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska |
title_full |
Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska |
title_fullStr |
Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska |
title_full_unstemmed |
Diet and movement of depredating male sperm whales (Physeter macrocephalus) in the Gulf of Alaska |
title_sort |
diet and movement of depredating male sperm whales (physeter macrocephalus) in the gulf of alaska |
publishDate |
2020 |
url |
http://hdl.handle.net/11122/11297 |
geographic |
Fairbanks Gulf of Alaska |
geographic_facet |
Fairbanks Gulf of Alaska |
genre |
Physeter macrocephalus Sperm whale Alaska |
genre_facet |
Physeter macrocephalus Sperm whale Alaska |
op_relation |
http://hdl.handle.net/11122/11297 College of Fisheries & Ocean Sciences |
_version_ |
1766168181543534592 |