Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8442
Title: Regional diving behavior of Pacific Arctic beluga whales (Delphinapterus leucas) and presumed associations with prey
Author: D.D.W. Hauser, Kristin L. Laidre, Sandra L. Parker-Stetter, John K. Horne, Robert S. Suydam, Pierre R. Richard
Publication Year: 2015
Journal: Marine Ecology Progress Series
Volume: 541
Pages: 246-264
DOI: 10.3354/meps11530
Keywords: diving behavior,Arctic marine ecology,foraging ecology,Arctic cod,Chukchi Sea,Beaufort Sea,
Abstract:

Two populations of beluga whales (Delphinapterus leucas) make extensive seasonal migrations in the Pacific Arctic to several regions characterized by diverse bathymetry and hydrography, yet there is limited information on behavior and foraging across regions. We used satellite tags equipped with time-depth recorders, attached to 30 belugas from two populations from 1997-2012, to infer the depths at which belugas forage regionally. We also used an acoustic survey conducted in the western Beaufort Sea to estimate vertically integrated densities of a prey species, Arctic cod (Boreogadus saida), to examine the correspondence between patterns of beluga diving in the survey area and Arctic cod abundance at depth. A suite of regional diving metrics showed that beluga dive behavior varied among regions and sometimes between populations. Occupancy time at depth as well as maximum and modal dive depths for 6-h periods suggested that Eastern Chukchi Sea (ECS) and Eastern Beaufort Sea (BS) belugas were regularly diving to the seafloor in the shallow shelf regions while specific portions of the water column were more frequently targeted along slope margins, and in the deep Canada Basin (>3,000 m). The greatest maximum daily depths were >900 m in Canada Basin. Arctic cod were most abundant at 200-300 m in the western Beaufort Sea, and dives located within the survey area also most frequently targeted these depths. These results are consistent with a hypothesis that Arctic cod are a primary prey item for Pacific Arctic belugas and that foraging belugas dive to depths that maximize prey encounters.

Description:

Examination of diving behavior of belugas in Chukchi and Beaufort Sea and comparison with acosutically-derived vertical distribution of their primary prey, Arctic cod.

Theme: Ecosystem approach to improve management of marine resources
Foci: Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species.
Official Citation:

Hauser, D.L., K.L. Laidre, S.L. Parker-Stetter, J.K. Horne, R.S. Suydam, and P.R. Richards. Regional diving behavior of Pacific Arctic beluga whales (Delphinapterus leucas) and presumed associations with prey. Marine Ecology Progress Series.