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Killer whales (Orcinus orca) in the Canadian Arctic: Distribution, prey items, group sizes, and seasonality

Authors

  • Jeff W. Higdon,

    1. Department of Environment and Geography,
      University of Manitoba,
      501 University Crescent,
      Winnipeg, Manitoba R3T 2N6, Canada
      and
      Fisheries and Oceans Canada,
      Central and Arctic Region,
      501 University Crescent,
      Winnipeg, Manitoba R3T 2N6, Canada
      E-mail: jeff.higdon@gmail.com
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  • Donna D. W. Hauser,

    1. 78 Marine Drive,
      Logy Bay, Newfoundland A1K 3C7, Canada
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    • Current address: LGL Limited environmental research associates, PO Box 13248 Station A, St. John's, Newfoundland A1B 4A5, Canada.

  • Steven H. Ferguson

    1. Fisheries and Oceans Canada,
      Central and Arctic Region,
      501 University Crescent,
      Winnipeg, Manitoba R3T 2N6, Canada
      and
      Department of Environment and Geography,
      University of Manitoba,
      501 University Crescent,
      Winnipeg, Manitoba R3T 2N6, Canada
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Abstract

Killer whales (Orcinus orca) have a global distribution, but many high-latitude populations are not well studied. We provide a comprehensive review of the history and ecology of killer whales in the Canadian Arctic, for which there has previously been little information. We compiled a database of 450 sightings spanning over 15 decades (1850–2008) to document the historical occurrence, distribution, feeding ecology, and seasonality of killer whales observed throughout the region. Sighting reports per decade increased substantially since 1850 and were most frequent in the eastern Canadian Arctic. The mean reported group size was 8.3 (median = 4, range 1–100), but size varied significantly among regions and observed prey types. Observations of predation events indicate that Canadian Arctic killer whales prey upon other marine mammals. Monodontids were the most frequently observed prey items, followed by bowhead whales (Balaena mysticetus), phocids, and groups of mixed mammal prey. No killer whale sightings occurred during winter, with sightings gradually increasing from early spring to a peak in summer, after which sightings gradually decreased. Our results suggest that killer whales are established, at least seasonally, throughout the Canadian Arctic, and we discuss potential ecological implications of increased presence with declining sea ice extent and duration.

Ancillary