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Mark–recapture using tetracycline and genetics reveal record-high bear density

Authors

  • Elizabeth Peacock,

    Corresponding author
    1. Program in Ecology, Evolution, and Conservation Biology, University of Nevada—Reno, Reno, NV 89557, USA
    Current affiliation:
    1. U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK, USA 99508.
    • Program in Ecology, Evolution, and Conservation Biology, University of Nevada—Reno, Reno, NV 89557, USA.
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  • Kimberly Titus,

    1. Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 115526, Juneau, AK 99811, USA
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  • David L. Garshelis,

    1. Minnesota Department of Natural Resources, 1201 E. Highway 2, Grand Rapids, MN 55744, USA
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  • Mary M. Peacock,

    1. Program in Ecology, Evolution, and Conservation Biology and Department of Biology, University of Nevada—Reno, Reno, NV 89557, USA
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  • Miroslaw Kuc

    1. PH205—942 Yonge Street, Toronto, Ontario, Canada M4W 3S8
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  • Associate Editor: Scott M. McCorquodale

Abstract

We used tetracycline biomarking, augmented with genetic methods to estimate the size of an American black bear (Ursus americanus) population on an island in Southeast Alaska. We marked 132 and 189 bears that consumed remote, tetracycline-laced baits in 2 different years, respectively, and observed 39 marks in 692 bone samples subsequently collected from hunters. We genetically analyzed hair samples from bait sites to determine the sex of marked bears, facilitating derivation of sex-specific population estimates. We obtained harvest samples from beyond the study area to correct for emigration. We estimated a density of 155 independent bears/100 km2, which is equivalent to the highest recorded for this species. This high density appears to be maintained by abundant, accessible natural food. Our population estimate (approx. 1,000 bears) could be used as a baseline and to set hunting quotas. The refined biomarking method for abundance estimation is a useful alternative where physical captures or DNA-based estimates are precluded by cost or logistics. © 2011 The Wildlife Society.

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