Assessment of genetic structure among eastern North Pacific gray whales on their feeding grounds

Authors

  • Aimée R. Lang,

    Corresponding author
    1. Marine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, California 92037, U.S.A
    2. Ocean Associates Incorporated, Arlington, Virginia 22207, U.S.A
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  • John Calambokidis,

    1. Cascadia Research Collective, Olympia, Washington 98501, U.S.A
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  • Jonathan Scordino,

    1. Marine Mammal Program, Makah Fisheries Management, Makah Tribe, Neah Bay, Washington 98357, U.S.A
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  • Victoria L. Pease,

    1. Marine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, California 92037, U.S.A
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  • Amber Klimek,

    1. Cascadia Research Collective, Olympia, Washington 98501, U.S.A
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  • Vladimir N. Burkanov,

    1. National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Seattle, Washington 98115, U.S.A
    2. Kamchatka Branch of the Pacific Geographical Institute, Russian Academy of Sciences, Petropavlovsk-Kamchatsky, Kamchatka 683000, Russia
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  • Pat Gearin,

    1. Kamchatka Branch of the Pacific Geographical Institute, Russian Academy of Sciences, Petropavlovsk-Kamchatsky, Kamchatka 683000, Russia
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  • Dennis I. Litovka,

    1. Marine Mammal Laboratory, Chukotka Branch of FGUP-TINRO, Anadyr, Chukotka 689000, Russia
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  • Kelly M. Robertson,

    1. Marine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, California 92037, U.S.A
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  • Bruce R. Mate,

    1. Marine Mammal Institute, Oregon State University, Hatfield Marine Science Center, Newport, Oregon 97365, U.S.A
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  • Jeff K. Jacobsen,

    1. Humboldt State University, Department of Biological Sciences, Arcata, California, U.S.A
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  • Barbara L. Taylor

    1. Marine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, California 92037, U.S.A
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Abstract

Although most eastern North Pacific (ENP) gray whales feed in the Bering, Beaufort, and Chukchi Seas during summer and fall, a small number of individuals, referred to as the Pacific Coast Feeding Group (PCFG), show intra- and interseasonal fidelity to feeding areas from northern California through southeastern Alaska. We used both mitochondrial DNA (mtDNA) and 12 microsatellite markers to assess whether stock structure exists among feeding grounds used by ENP gray whales. Significant mtDNA differentiation was found when samples representing the PCFG (n = 71) were compared with samples (n = 103) collected from animals feeding further north (FST = 0.012, P = 0.0045). No significant nuclear differences were detected. These results indicate that matrilineal fidelity plays a role in creating structure among feeding grounds but suggests that individuals from different feeding areas may interbreed. Haplotype diversities were similar between strata (hPCFG = 0.945, hNorthern = 0.952), which, in combination with the low level of mtDNA differentiation identified, suggested that some immigration into the PCFG could be occurring. These results are important in evaluating the management of ENP gray whales, especially in light of the Makah Tribe's proposal to resume whaling in an area of the Washington coast utilized by both PCFG and migrating whales.

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