Journal Article

An assessment of Greenland walrus populations

Lars Witting and Erik W. Born

in ICES Journal of Marine Science

Published on behalf of ICES/CIEM

Volume 62, issue 2, pages 266-284
Published in print January 2005 | ISSN: 1054-3139
Published online January 2005 | e-ISSN: 1095-9289 | DOI: http://dx.doi.org/10.1016/j.icesjms.2004.11.001
An assessment of Greenland walrus populations

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Recent abundance estimates were combined with historical catches and an age- and sex-structured population dynamic model to perform Bayesian assessments of the walrus (Odobenus rosmarus) populations in West Greenland, the North Water in northern Baffin Bay, and East Greenland. The model assumed density-regulated dynamics and pre-harvest populations in population-dynamical equilibrium. It projected the populations under the influence of the catches to estimate the historical trajectories and the current population status. It was found that the West Greenland and North Water populations have been heavily exploited during the last century with the current abundance being at best only a few per cent of the historical abundance. Apparently these populations are still being exploited above sustainable level. The East Greenland population was heavily exploited after 1889 and during the first half of the 20th century and was depleted to approximately 50% of pristine population size in 1933. After protective measures were introduced in the 1950s this population has increased to a current level close to the abundance in 1889, and the present exploitation appears to be sustainable.

Keywords: Bayesian statistics; density regulation; Greenland; marine mammal; modelling; Odobenus rosmarus; population dynamics; sustainable exploitation; walrus

Journal Article.  12107 words.  Illustrated.

Subjects: Environmental Science ; Marine and Estuarine Biology

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