Are Antarctic minke whales unusually abundant because of 20th century whaling?

Authors

  • KRISTEN C. RUEGG,

    1. Department of Biology, Hopkins Marine Station, Stanford University, 120 Oceanview Boulevard, Pacific Grove, CA 93950, USA
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  • ERIC C. ANDERSON,

    1. Southwest Fisheries Science Center, National Marine Fisheries Service, 110 Shaffer Road, Santa Cruz, CA 95060, USA
    2. Department of Applied Math and Statistics, University of California, Santa Cruz, CA 95060, USA
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  • C. SCOTT BAKER,

    1. Marine Mammal Institute, Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, OR 97365, USA
    2. School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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  • MURDOCH VANT,

    1. School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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  • JENNIFER A. JACKSON,

    1. Marine Mammal Institute, Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, OR 97365, USA
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  • STEPHEN R. PALUMBI

    1. Department of Biology, Hopkins Marine Station, Stanford University, 120 Oceanview Boulevard, Pacific Grove, CA 93950, USA
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Kristen C. Ruegg, Fax: 831-655-6215; E-mail: kruegg@stanford.edu

Abstract

Severe declines in megafauna worldwide illuminate the role of top predators in ecosystem structure. In the Antarctic, the Krill Surplus Hypothesis posits that the killing of more than 2 million large whales led to competitive release for smaller krill-eating species like the Antarctic minke whale. If true, the current size of the Antarctic minke whale population may be unusually high as an indirect result of whaling. Here, we estimate the long-term population size of the Antarctic minke whale prior to whaling by sequencing 11 nuclear genetic markers from 52 modern samples purchased in Japanese meat markets. We use coalescent simulations to explore the potential influence of population substructure and find that even though our samples are drawn from a limited geographic area, our estimate reflects ocean-wide genetic diversity. Using Bayesian estimates of the mutation rate and coalescent-based analyses of genetic diversity across loci, we calculate the long-term population size of the Antarctic minke whale to be 670 000 individuals (95% confidence interval: 374 000–1 150 000). Our estimate of long-term abundance is similar to, or greater than, contemporary abundance estimates, suggesting that managing Antarctic ecosystems under the assumption that Antarctic minke whales are unusually abundant is not warranted.

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