Sex-specific diet of harbor seals (Phoca vitulina) in the Salish Sea
Research Mentor(s)
Dr. Alejandro Acevedo-Gutiérrez
Description
The lack of recovery of Chinook salmon (Oncorhynchus tshawytscha) in the Pacific Northwest has been blamed in part on predation by pinnipeds, particularly the harbor seal (Phoca vitulina). These concerns are compounded by the different impact that male and female harbor seals appear to have on Chinook salmon relative to their proportions on haul-out sites. To address these concerns, we are examining sex-specific biases for Chinook salmon and estimating the sex ratios of harbor seal haul-out locations in the Salish Sea—the inland waters of Washington State and the province of British Columbia—across 13 sites during 2012-2018. DNA metabarcoding analysis was conducted on approximately 2,264 seal scats (used in linear modeling) to determine the proportions of prey species in the diet of each. The sex of harbor seals was determined from each scat matrix sample with the use of quantitative polymerase chain reaction. We found that sex ratio varied across the Salish Sea and was mostly influenced by site and year. We plan to analyze diet data from a wide range of sites and years and determine if a previously reported male bias for salmon is generalizable to the region, allowing the description of potential predation hot spots.
Document Type
Event
Start Date
May 2022
End Date
May 2022
Location
Carver Gym (Bellingham, Wash.)
Department
CSE - Biology
Genre/Form
student projects; posters
Type
Image
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Language
English
Format
application/pdf
Sex-specific diet of harbor seals (Phoca vitulina) in the Salish Sea
Carver Gym (Bellingham, Wash.)
The lack of recovery of Chinook salmon (Oncorhynchus tshawytscha) in the Pacific Northwest has been blamed in part on predation by pinnipeds, particularly the harbor seal (Phoca vitulina). These concerns are compounded by the different impact that male and female harbor seals appear to have on Chinook salmon relative to their proportions on haul-out sites. To address these concerns, we are examining sex-specific biases for Chinook salmon and estimating the sex ratios of harbor seal haul-out locations in the Salish Sea—the inland waters of Washington State and the province of British Columbia—across 13 sites during 2012-2018. DNA metabarcoding analysis was conducted on approximately 2,264 seal scats (used in linear modeling) to determine the proportions of prey species in the diet of each. The sex of harbor seals was determined from each scat matrix sample with the use of quantitative polymerase chain reaction. We found that sex ratio varied across the Salish Sea and was mostly influenced by site and year. We plan to analyze diet data from a wide range of sites and years and determine if a previously reported male bias for salmon is generalizable to the region, allowing the description of potential predation hot spots.