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...
| Main Authors: | , , , |
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| Format: | Dataset |
| Language: | unknown |
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2020
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| Online Access: | https://zenodo.org/record/4998604 https://doi.org/10.5061/dryad.8th871g |
| Summary: | 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 analyzed tissue samples from sperm whales and seven potential prey (five groundfish and two squid species). Samples were analyzed 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. Sperm whale diet in the Gulf of Alaska analysis repositoryThis repository contains r-scripts/r-project and downloadable .csv data files used to reproduce all analysis done in this manuscript.Sperm Whale Diet DataAll diet data used in this analysis is available through GitHub at https://github.com/LaurenWild/UAF_SpermWhale_Diet.git. This includes all r-script files and raw data files, downloadable.Sperm Whale Diet AnalysisR project file (and associated csv files) for analysis done on this manuscript. This includes isotope analysis, including dietary mixing models, of sperm whales and their major groundfish and squid prey in the Gulf of Alaska.UAF_SpermWhale_Diet_Isotopes.RprojBiopsy_DetailsBiopsy Data for Creating MapsSperm whale isotope datasperm ... |
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