Movements of walruses radio-tagged in Bristol Bay, Alaska

Arctic
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Abstract

Satellite radio-location data from 57 adult male Pacific walruses (Odobenus rosmarus divergens) were used to estimate haul-out fidelity, broadly describe seasonal foraging distributions, and determine the approximate timing of autumn migration from Bristol Bay, Alaska. Data were collected intermittently during 1987–91 and 1995–2000, primarily during the period from May to October. Transmitter longevity ranged from less than 1 day to 560 days (median 75 d). The four tagging sites were the only haul-outs that were commonly used in the bay from spring through autumn. Mean fidelity, defined as the chance that an animal will return to an area where it previously hauled out, was 0.56 (SE = 0.09). However, small sample sizes precluded comparisons of fidelity among years and among haul-outs by season. No tagged animals migrated out of the bay between spring and early autumn. Combined monthly locations suggest that foraging occurred primarily in the southern and eastern areas of the bay in spring and gradually shifted towards northwestern areas in late autumn and winter. Ninety-eight percent of the in-water locations were in waters under 60 m deep, which account for 76% of the study area. Some animals migrated out of the bay in late autumn and winter; others remained within the bay throughout the year. Those making long-range migrations departed the bay during November and December.

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Publication type Article
Publication Subtype Journal Article
Title Movements of walruses radio-tagged in Bristol Bay, Alaska
Series title Arctic
DOI 10.14430/arctic410
Volume 58
Issue 2
Year Published 2005
Language English
Publisher Arctic Institute of North America
Contributing office(s) Alaska Science Center
Description 11 p.
First page 192
Last page 202
Country United States
State Alaska
Other Geospatial Bristol Bay
Online Only (Y/N) N
Additional Online Files (Y/N) N
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