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ESR 37:255-267 (2018)  -  DOI:

Population viability analysis of Guadalupe fur seals Arctocephalus townsendi

Claudia J. Hernández-Camacho1,*, Andrew W. Trites2

1Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, 23096 La Paz, Baja California Sur, México
2Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
*Corresponding author:

ABSTRACT: The Guadalupe fur seal Arctocephalus townsendi was intensively hunted and considered extinct by the end of the 1800s. However, small numbers (<20 seals) were reported on Guadalupe Island (Mexico) in the mid-1950s and were observed at a second location (San Benito Islands, Mexico) in the late 1990s. Sporadic counts at these 2 sites have followed a relatively rapid increase in numbers, but considerable uncertainty remains about the long-term viability of this recovering species. We performed a population viability analysis using historic seal counts from Guadalupe Island and the San Benito Islands to predict the probability of each colony (and both colonies combined) going extinct under 3 critical population threshold scenarios (100, 500, and 1000 seals). Using a diffusion approximation model, we found that the growth rates of the 2 colonies were similar (10-11% yr-1) and that the population totaled ~41000 individuals in 2017 (x̄ = 40614, 95% CI = 35779-46877). Guadalupe fur seals appear to be vulnerable to extreme climatic events. Of the 2 fur seal colonies, the San Benito Islands colony is less secure and is Endangered to Critically Endangered, depending on the quasi-extinction value used under the quantitative listing criteria established by the IUCN. In contrast, the Guadalupe Island colony and the 2 colonies combined meet the quantitative analysis criteria of Least Concern. Population viability analysis is an important component of assessing the status of wildlife populations and assisting nations and organizations in assigning appropriate categories of protection.

KEY WORDS: Guadalupe fur seal · Population viability analysis · PVA · Probability of extinction · Endangered species · Population trend · Pinnipeds

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Cite this article as: Hernández-Camacho CJ, Trites AW (2018) Population viability analysis of Guadalupe fur seals Arctocephalus townsendi. Endang Species Res 37:255-267.

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