thumbnail

New insights into the diets of harbor seals in the Salish Sea revealed by quantitative fatty acid signature analysis

Fishery Bulletin

By:
, , , , , and
DOI: 10.7755/FB.111.1.2

Links

Abstract

Harbor seals (Phoca vitulina) are an abundant predator along the west coast of North America, and there is considerable interest in their diet composition, especially in regard to predation on valued fish stocks. Available information on harbor seal diets, primarily derived from scat analysis, suggests that adult salmon (Oncorhynchus spp.), Pacific Herring (Clupea pallasii), and gadids predominate. Because diet assessments based on scat analysis may be biased, we investigated diet composition through quantitative analysis of fatty acid signatures. Blubber samples from 49 harbor seals captured in western North America from haul-outs within the area of the San Juan Islands and southern Strait of Georgia in the Salish Sea were analyzed for fatty acid composition, along with 269 fish and squid specimens representing 27 potential prey classes. Diet estimates varied spatially, demographically, and among individual harbor seals. Findings confirmed the prevalence of previously identified prey species in harbor seal diets, but other species also contributed significantly. In particular, Black (Sebastes melanops) and Yellowtail (S. flavidus) Rockfish were estimated to compose up to 50% of some individual seal diets. Specialization and high predation rates on Black and Yellowtail Rockfish by a subset of harbor seals may play a role in the population dynamics of these regional rockfish stocks that is greater than previously realized.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
Federal Government Series
Title:
New insights into the diets of harbor seals in the Salish Sea revealed by quantitative fatty acid signature analysis
Series title:
Fishery Bulletin
DOI:
10.7755/FB.111.1.2
Volume
111
Issue:
1
Year Published:
2012
Language:
English
Publisher:
NOAA, National Marine Fisheries Service
Contributing office(s):
Alaska Science Center Biology MFEB
Description:
14 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Fishery Bulletin
First page:
13
Last page:
26
Number of Pages:
14
Country:
Canada;United States
State:
British Columbia;Washington
Additional Online Files(Y/N):
N