|Scientific Name:||Eschrichtius robustus (western subpopulation)|
|Species Authority:||(Lilljeborg, 1861)|
This subpopulation of Eschrichtius robustus (Lilljeborg, 1861), called the western gray whale, is probably genetically isolated from the only other extant subpopulation, known as the eastern gray whale (LeDuc et al. 2002); the ranges do not appear to overlap (Blokhin 1996). It is listed separately for conservation and management purposes (see separate listing for the global species).
|Red List Category & Criteria:||Critically Endangered C2a(ii); E ver 3.1|
|Assessor/s:||Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell Jr., R.L., Butterworth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán, J. & Zerbini, A.N.|
|Reviewer/s:||Taylor, B.L. & Notarbartolo di Sciara, G. (Cetacean Red List Authority)|
Results of a quantitative population analysis (Cooke et al. 2006) indicate Critically Endangered under the assumption that recent mortality levels continue, based on an extinction probability exceeding 50% within three generations (criterion E), or a projected continuing decline of the subpopulation in combination with a mature population size less than 250 (criterion C2a(ii)). In addition, the small absolute subpopulation size, and the estimate of at most 35 reproductive females means that the subpopulation would easily qualify as Endangered under criterion D (< 250 mature individuals).
The western gray whale summers in the
Native:China; Japan; Korea, Democratic People's Republic of; Korea, Republic of; Russian Federation
|FAO Marine Fishing Areas:||
Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
Western gray whales were thought to be extinct as recently as 1972 (Bowen 1974), but a small number are now known to survive (Berzin 1974, Weller et al. 2002); the best estimate for 2006 is 113-131 animals, of which 26-35 are reproductive females, based on an analysis of photo-identification data (Cooke et al. 2006). The figures include adjustments for the photo-identified whales that are likely to have died and for the estimated number of living whales that have yet to be catalogued. In the absence of additional new mortality in excess of the estimated rate over 1994-2004, the population size is projected to increase at 2-4% per annum (Cooke et al. 2006). However, even a very small number of additional annual female deaths will cause the subpopulation to decline.
|Habitat and Ecology:||
The main feeding habitat of this subpopulation
is the shallow (5-15 m depth) shelf of northeastern
Western gray whales
were hunted by aboriginal people in the northern part of their range since
prehistoric times but to an unknown extent (Mitchell, 1979). They were taken by
Japanese hand-harpoon whalers in the
Three western gray whales, all females, were
fatally entangled in net-traps on the Pacific coast of
The substantial nearshore industrialization and shipping congestion throughout the migratory corridors of this subpopulation represent potential threats by increasing the likelihood of exposure to ship strikes, chemical pollution, and general disturbance (Weller et al. 2002).
Offshore gas and oil development in the
International Whaling Commission (IWC)
regulations protect western gray whales from commercial and aboriginal
subsistence whaling; the range states of the
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|Citation:||Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell Jr., R.L., Butterworth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán, J. & Zerbini, A.N. 2000. Eschrichtius robustus (western subpopulation). In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 18 May 2013.|
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