ESR 18:193-199 (2012)  -  DOI: https://doi.org/10.3354/esr00447

FEATURE ARTICLE
Movements of gray whales between the western and eastern North Pacific

David W. Weller1,*, Amber Klimek2, Amanda L. Bradford3, John Calambokidis2, Aimee R. Lang1, Brian Gisborne4, Alexander M. Burdin5, Wendy Szaniszlo6, Jorge Urbán7, Alejandro Gómez-Gallardo Unzueta 7, Steven Swartz8, Robert L. Brownell Jr.

1Protected Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 3333 North Torrey Pines Court, La Jolla, California 92037-1022, USA
2Cascadia Research Collective, Olympia, Washington 98501, USA
3Protected Species Division, Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Honolulu, Hawaii 96814, USA
4Juan de Fuca Express, Victoria, British Columbia, Canada
5Kamchatka Branch of Pacific Institute of Geography, Far East Branch - Russian Academy of Sciences, Petropavlovsk, Kamchatka, Russia
6PO Box 486, Ucluelet, British Columbia, Canada
7Programa de Investigación de Mamíferos Marinos, Universidad Autónoma de Baja California Sur, La Paz, B.C.S., Mexico
8Cetacean Research Associates, Darnestown, Maryland 20874, USA

ABSTRACT: The western North Pacific (WNP) population of gray whales Eschrichtius robustus is redlisted by the IUCN as Critically Endangered. As part of a long-term study on whales off Sakhalin Island, Russia, photo-catalog comparisons of gray whales in the western and eastern North Pacific (ENP) were undertaken to assess population mixing. These comparisons involved 2 approaches: (1) a systematic comparison of the WNP ‘Sakhalin Catalog’ to an ENP ‘Pacific Northwest Catalog’ that consisted of images from the northwest coast of North America and (2) a non-systematic comparison of the WNP ‘Sakhalin Catalog’ to an ENP ‘Laguna San Ignacio Catalog’ that consisted of images from central Baja California, Mexico. The Sakhalin to Pacific Northwest comparison consisted of 181 and 1064 whales, respectively, and resulted in 6 matches (3 males, 2 females, and 1 whale of unknown sex). All sightings of ‘Sakhalin whales’ in the Pacific Northwest occurred off southern Vancouver Island, British Columbia, Canada. The Sakhalin to Laguna San Ignacio comparison consisted of 181 and 2514 whales, respectively, and resulted in 4 matches (2 males and 2 females). As the Pacific Northwest and Laguna San Ignacio catalogs represent only a small fraction of the total estimated number of individuals in the ENP population (~19000), it is likely that more WNP/ENP exchange has occurred than was detected by these photo-catalog comparisons. Although these matches provide new records of movements between the WNP and ENP, recent observations of gray whales off Japan and China suggest that not all gray whales identified in the WNP share a common wintering ground.


KEY WORDS: Gray whale · Pacific Ocean · Movement patterns · Conservation


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Cite this article as: Weller DW, Klimek A, Bradford AL, Calambokidis J and others (2012) Movements of gray whales between the western and eastern North Pacific. Endang Species Res 18:193-199. https://doi.org/10.3354/esr00447

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