Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis
Sperm whales interact with commercially important groundfish fisheries offshore in the Gulf of Alaska (GOA). This study aims to use stable isotope analysis to better understand the trophic variability of sperm whales and their potential prey, and to use dietary mixing models to estimate the importan...
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doaj-741fc420e0bd4ffba663b8df4eb0296f2020-11-25T03:09:37ZengThe Royal SocietyRoyal Society Open Science2054-57032020-03-017310.1098/rsos.191110191110Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysisLauren A. WildFranz MueterBriana WitteveenJanice M. StraleySperm whales interact with commercially important groundfish fisheries offshore in the Gulf of Alaska (GOA). This study aims to use stable isotope analysis to better understand the trophic variability of sperm whales and their potential prey, and to use dietary mixing models to estimate the importance of prey species to sperm whale diets. We analysed tissue samples from sperm whales and seven potential prey (five groundfish and two squid species). Samples were analysed for stable carbon and nitrogen isotope ratios, and diet composition was estimated using Bayesian isotopic mixing models. Mixing model results suggest that an isotopically combined sablefish/dogfish group, skates and rockfish make up the largest proportion of sperm whale diets (35%, 28% and 12%) in the GOA. The top prey items of whales that interact more frequently with fishing vessels consisted of skates (49%) and the sablefish/dogfish group (24%). This is the first known study to provide an isotopic baseline of adult male sperm whales and these adult groundfish and offshore squid species, and to assign contributions of prey to whale diets in the GOA. This study provides information to commercial fishermen and fisheries managers to better understand trophic connections of important commercial species.https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.191110stable isotope analysissperm whalesgulf of alaskadietary mixing models |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Lauren A. Wild Franz Mueter Briana Witteveen Janice M. Straley |
spellingShingle |
Lauren A. Wild Franz Mueter Briana Witteveen Janice M. Straley Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis Royal Society Open Science stable isotope analysis sperm whales gulf of alaska dietary mixing models |
author_facet |
Lauren A. Wild Franz Mueter Briana Witteveen Janice M. Straley |
author_sort |
Lauren A. Wild |
title |
Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis |
title_short |
Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis |
title_full |
Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis |
title_fullStr |
Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis |
title_full_unstemmed |
Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis |
title_sort |
exploring variability in the diet of depredating sperm whales in the gulf of alaska through stable isotope analysis |
publisher |
The Royal Society |
series |
Royal Society Open Science |
issn |
2054-5703 |
publishDate |
2020-03-01 |
description |
Sperm whales interact with commercially important groundfish fisheries offshore in the Gulf of Alaska (GOA). This study aims to use stable isotope analysis to better understand the trophic variability of sperm whales and their potential prey, and to use dietary mixing models to estimate the importance of prey species to sperm whale diets. We analysed tissue samples from sperm whales and seven potential prey (five groundfish and two squid species). Samples were analysed for stable carbon and nitrogen isotope ratios, and diet composition was estimated using Bayesian isotopic mixing models. Mixing model results suggest that an isotopically combined sablefish/dogfish group, skates and rockfish make up the largest proportion of sperm whale diets (35%, 28% and 12%) in the GOA. The top prey items of whales that interact more frequently with fishing vessels consisted of skates (49%) and the sablefish/dogfish group (24%). This is the first known study to provide an isotopic baseline of adult male sperm whales and these adult groundfish and offshore squid species, and to assign contributions of prey to whale diets in the GOA. This study provides information to commercial fishermen and fisheries managers to better understand trophic connections of important commercial species. |
topic |
stable isotope analysis sperm whales gulf of alaska dietary mixing models |
url |
https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.191110 |
work_keys_str_mv |
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