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Endangered Species
Gray
Whale
Eschrichtius robustus
Over two
decades ago, the West Coast Whale Research (now
Pacific WildLife
Foundation) pioneered studies of the gray whales off Vancouver Island, and
thanks to donor support the studies continue.
The coastal
dwelling gray whale is the most often encountered whale on the Pacific Coast of
North America and the object of a flourishing whale-watching industry. Gray
whales are distinctive from other whales by the combination of medium size (for
a whale: 10-15m), mottled gray skin pigmentation, absence of a dorsal fin, and
propensity to come very close to shore.
The eastern Pacific
population, sometimes referred to as the California stock, calves off the coast
of Baja California and most individuals spend the summer feeding in the Bering
and Chukchi Seas. Small numbers spend the summer feeding off southeast Alaska,
British Columbia, Washington, Oregon and California. The eastern Pacific
population is thought to be about 20,000 individuals, down somewhat from
estimates of few years ago of up to 26.000.
Some scientists
suggest the population has reached its capacity, noting that large numbers of
strandings in recent years may have been the result of starvation. The
average of
41 stranded gray whales reported between 1995 and 1998, was followed by a large
increase to 283 strandings in 1999 and 368 in 2000. However, the number of
strandings fell to 21 in 2001 and 26 in 2002. Researchers concluded that no
clear explanation could be derived for the stranded whales but that a common,
wide ranging factor was likely involved and that starvation was most likely (Gulland
et al 2005).
The western Pacific
gray whale population sometimes referred to as the Korean stock, is composed of
just 100 animals and is considered critically endangered. Western gray whales
spend the summer feeding near Sakhalin Island. Their breeding ground is unknown
but suspected to be in the waters off southern China.
References
Baird, R.W., P.J.
Stacey, D.A. Duffus and K.M. Langelier. 2002. An evaluation of gray whale (Eschrichtius
robustus) mortality incidental to fishing operations in British
Columbia, Canada. Journal of Cetacean Research and Management 4:289-296.
Bowen, W. D. and D. B. Siniff. 1999. Distribution, population
biology and feeding ecology of marine mammals. Pp. 423-484 in
Reynolds, J. E., III and S. A. Rommel (eds.). Biology of marine mammals.
Smithsonian Institution, Washington DC
Breiwick, J. W. 1999. Gray
whale abundance estimates, Pp. 62 in D. J. Rugh, M. M. Muto, S. E. Moore and D.
P. DeMaster. Status review of the eastern north pacific stock of gray whales. US
Department of Commerce. NOAA Tech Rep. Memo NMFS-AFSC-103, Washington, D.C.
Darling,
J.D. 1984. Gray whales off Vancouver Island, British Columbia. Pp. 276 – 287 in
The Gray Whale. M. L.
Jones, S. Swartz and S. Leatherwood (eds.). Academic Press, New York, NY.
Darling, J.D., Keogh, K.E.,
and T.E. Steeves. 1998. Gray whale (Eschrichtius robustus) habitat utilization
and prey species off Vancouver Island, B.C. Marine Mammal Science 14, 692-720.
Gulland, F.M.D. and others.
2005. Eastern North Pacific gray whale (Eschrictius
robustus) unusual mortality event,
1999-2000. NOAA Technical Memorandum NMFS-AFSC-150.
Rice, D. W. and A. A. Wolman.
1971. The life history and ecology of the gray whale Eschrichtius robustus.
American Society of Mammalogists, Special Publication 3, 142 p.
Wartzok, D.
and D. R. Ketten. 1999. Marine mammals sensory systems. Pp. 117-175 in Reynolds,
J. E., III and S. A. Rommel (eds.). Biology of marine mammals. Smithsonian
Institution, Washington DC
Wilson, D. E. and S. Ruff. 1999. The Smithsonian book of North
American mammals. Smithsonian Institution, Washington, D.C.
Gray Whale Identification Guide
Gray Whale Distribution Map
Gray
Whale Photos
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