Pacific Walrus (Odobenus rosmarus divergens) Resource Selection in the Northern Bering Sea

The Pacific walrus is a large benthivore with an annual range extending across the continental shelves of the Bering and Chukchi Seas. We used a discrete choice model to estimate site selection by adult radio-tagged walruses relative to the availability of the caloric biomass of benthic infauna and...

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Bibliographic Details
Published in:PLoS ONE
Main Authors: Jay, Chadwick V., Grebmeier, Jacqueline M., Fischbach, Anthony S., McDonald, Trent L., Cooper, Lee W., Hornsby, Fawn
Format: Text
Language:English
Published: Public Library of Science 2014
Subjects:
Research Article
Bering Sea
Lawrence Island
Pacific
Chukchi
Odobenus rosmarus
Sea ice
St Lawrence Island
walrus*
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3981674
http://www.ncbi.nlm.nih.gov/pubmed/24717979
https://doi.org/10.1371/journal.pone.0093035
Description
Summary:The Pacific walrus is a large benthivore with an annual range extending across the continental shelves of the Bering and Chukchi Seas. We used a discrete choice model to estimate site selection by adult radio-tagged walruses relative to the availability of the caloric biomass of benthic infauna and sea ice concentration in a prominent walrus wintering area in the northern Bering Sea (St. Lawrence Island polynya) in 2006, 2008, and 2009. At least 60% of the total caloric biomass of dominant macroinfauna in the study area was composed of members of the bivalve families Nuculidae, Tellinidae, and Nuculanidae. Model estimates indicated walrus site selection was related most strongly to tellinid bivalve caloric biomass distribution and that walruses selected lower ice concentrations from the mostly high ice concentrations that were available to them (quartiles: 76%, 93%, and 99%). Areas with high average predicted walrus site selection generally coincided with areas of high organic carbon input identified in other studies. Projected decreases in sea ice in the St. Lawrence Island polynya and the potential for a concomitant decline of bivalves in the region could result in a northward shift in the wintering grounds of walruses in the northern Bering Sea.

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