Requirements and availability of prey for northeastern pacific southern resident killer whales.

The salmon-eating Southern Resident killer whale (SRKW) (Orcinus orca) population currently comprises only 73 individuals, and is listed as 'endangered' under the Species at Risk Act in Canada. Recent evidence suggests that the growth of this population may be limited by food resources, es...

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Main Authors: Fanny Couture, Greig Oldford, Villy Christensen, Lance Barrett-Lennard, Carl Walters
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0270523
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author Fanny Couture
Greig Oldford
Villy Christensen
Lance Barrett-Lennard
Carl Walters
author_facet Fanny Couture
Greig Oldford
Villy Christensen
Lance Barrett-Lennard
Carl Walters
author_sort Fanny Couture
collection DOAJ
description The salmon-eating Southern Resident killer whale (SRKW) (Orcinus orca) population currently comprises only 73 individuals, and is listed as 'endangered' under the Species at Risk Act in Canada. Recent evidence suggests that the growth of this population may be limited by food resources, especially Chinook salmon (Oncorhynchus tshawytscha). We present spatio-temporal bioenergetics model for SRKW in the Salish Sea and the West Coast of Vancouver Island from 1979-2020 with the objective of evaluating how changes in the abundance, age-structure, and length-at-age of Chinook salmon populations has influenced the daily food consumption of the SRKW population. Our model showed that the SRKW population has been in energetic deficit for six of the last 40 years. Our results also suggested that the abundance of age-4 and age-5 Chinook salmon are significant predictors of energy intake for SRKW. We estimated that the annual consumption (April-October) of Chinook salmon by the whales between 1979 and 2020 ranged from 166,000 216,300. Over the past 40 years, the model estimated that the contribution in the predicted SRKW diet of Chinook salmon originating from the Columbia River has increased by about 34%, and decreased by about 15% for Chinook salmon stocks originating from Puget Sound. Overall, our study provides an overview of the requirements and availability of prey for SRKW over the last 40 years, while supporting the hypothesis that SRKW were limited by prey abundance in the study period.
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spelling doaj.art-24a5ea015a1349f99b49e6fc6e94834d2022-12-22T03:43:11ZengPublic Library of Science (PLoS)PLoS ONE1932-62032022-01-01176e027052310.1371/journal.pone.0270523Requirements and availability of prey for northeastern pacific southern resident killer whales.Fanny CoutureGreig OldfordVilly ChristensenLance Barrett-LennardCarl WaltersThe salmon-eating Southern Resident killer whale (SRKW) (Orcinus orca) population currently comprises only 73 individuals, and is listed as 'endangered' under the Species at Risk Act in Canada. Recent evidence suggests that the growth of this population may be limited by food resources, especially Chinook salmon (Oncorhynchus tshawytscha). We present spatio-temporal bioenergetics model for SRKW in the Salish Sea and the West Coast of Vancouver Island from 1979-2020 with the objective of evaluating how changes in the abundance, age-structure, and length-at-age of Chinook salmon populations has influenced the daily food consumption of the SRKW population. Our model showed that the SRKW population has been in energetic deficit for six of the last 40 years. Our results also suggested that the abundance of age-4 and age-5 Chinook salmon are significant predictors of energy intake for SRKW. We estimated that the annual consumption (April-October) of Chinook salmon by the whales between 1979 and 2020 ranged from 166,000 216,300. Over the past 40 years, the model estimated that the contribution in the predicted SRKW diet of Chinook salmon originating from the Columbia River has increased by about 34%, and decreased by about 15% for Chinook salmon stocks originating from Puget Sound. Overall, our study provides an overview of the requirements and availability of prey for SRKW over the last 40 years, while supporting the hypothesis that SRKW were limited by prey abundance in the study period.https://doi.org/10.1371/journal.pone.0270523
spellingShingle Fanny Couture
Greig Oldford
Villy Christensen
Lance Barrett-Lennard
Carl Walters
Requirements and availability of prey for northeastern pacific southern resident killer whales.
PLoS ONE
title Requirements and availability of prey for northeastern pacific southern resident killer whales.
title_full Requirements and availability of prey for northeastern pacific southern resident killer whales.
title_fullStr Requirements and availability of prey for northeastern pacific southern resident killer whales.
title_full_unstemmed Requirements and availability of prey for northeastern pacific southern resident killer whales.
title_short Requirements and availability of prey for northeastern pacific southern resident killer whales.
title_sort requirements and availability of prey for northeastern pacific southern resident killer whales
url https://doi.org/10.1371/journal.pone.0270523
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