Estimates of Minimum Population Size for Walrus near Southeast Baffin Island, Nunavut

NAMMCO Scientific Publications

Rune Dietz¹  Anna K Ryan²  Robert EA Stewart³  Erik W Born⁴ 

[1] Department of Bioscience, Aarhus University;Department of Fisheries and Oceans, Freshwater Institute;Fisheries and Oceans Canada, Freshwater Institute;Greenland Institute of Natural Resources;

关键词: walrus;    Odobenus rosmarus;    Canada;    Greenland;    minimum counted population;    aerial surveys;    abundance;   

DOI  :  10.7557/3.2615

来源: DOAJ

【 摘 要 】

To support management objectives in Canada and Greenland, joint research between the Department of Fisheries and Oceans and Greenland Institute of Natural Resources was begun in 2005. Direct counts were used to determine the Minimum Counted Population (MCP) in summer around SE Baffin Island. Aerial surveys examined the coast from roughly the Saddleback Island in northern Hudson Strait to Isabella Bay on eastern Baffin Island but concentrated on the area between Loks Land and Cape Dyer. The maximum count was obtained on 3–4 September 2007 during boat surveys. The MCP ranged from 716 (in 2006) to 1,056 (2007). Using the largest MCP adjusted with published maximum estimates of the proportion of walrus hauled out concurrently, we estimated 1,420 (95% CI: 1,219–1,622) walrus were present. In addition, four walrus had been fitted with satellite relayed data logger tags prior to the maximum counts in 2007. Using the simple proportion of ‘tags dry’ on 3 September to adjust counts on 3 and 4 September 2007 provided an estimate of 2,102 (CI = MCP-4,482). Using the proportion of time dry immediately preceding the survey to adjust the maximum count produced an estimate of 2,502 (CI = 1,660–3,345) walrus were present in Hoare Bay. We conclude approximately 2,100–2,500 walrus were present in Hoare Bay in late summer 2007. This number is a negatively biased estimator of the population of walrus around SE Baffin Island and in the Hudson Bay–Davis Strait stock as a whole. Broader survey coverage in a short period and more detailed information on the movement of walrus between Greenland and Canada and the summer dispersal of these animals within Canada are required to improve population estimates.

【 授权许可】

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