Subject: Gray whale populations (fwd)

Mike Williamson (pita@www1.wheelock.edu)
Tue, 15 Sep 1998 13:48:16 -0400 (EDT)

Subject: Gray whale populations

Graham Clarke's posting on the Makah contains one rather large error:
the statement that the eastern gray whale represents the only remaining
population of this species.  The western gray whale remains extant,
despite a 1970's paper announcing its extinction (Bowen 1974).  The
population size is clearly small; the current guess is around 250
individuals (Berzin 1990, Vladimirov 1994) but no good numbers are
available.  It is clearly not abundant.  Western gray whales summer (at
least some do) in the Okhotsk Sea, where they are currently the subject
of a joint U.S.-Russian study off Sakhalin Island.

Western grays were hunted into the 1960's by Korea (Kato & Kasuya 1997),
and very likely illegally by the Soviet Union.  This relatively recent
exploitation at least partly explains the lack of recovery of the
population, which stands in sharp contrast to the full recovery of the
eastern stock (by the way, it's highly unlikely that the latter would
reach >300,000 animals - there's such a thing as carrying capacity!)

One of the most pressing questions regarding the western gray whale is
where it breeds, and whether problems exist at this end of its range.
No one knows the location of breeding grounds, or even if these animals
are dependent upon coastal lagoons for calving (like their eastern
counterparts).  Henderson (1990) examined whaling records and suggested
that gray whales may breed along the coast of China, but currently there
are too few data to address this question.  A pity, because if western
grays are indeed dependent upon coastal lagoons, it is quite possible
that habitat degradation or other human-related problems represent a
major impediment to this population's recovery.

None of this affects the various issues raised by the Makah controversy;
but readers should know that the eastern gray whale is not the only
population of the species left.  Indeed, the western population is among
the most critically endangered of all whale stocks worldwide - if the
guesstimates are in the ballpark, it's on a par with northern right
whale populations.  It deserves far greater attention from scientists
and conservationists than it has so far received.

Phil Clapham
Northeast Fisheries Science Center
Woods Hole, Massachusetts
phillip.clapham@noaa.gov


Literature cited
----------------
        Berzin, A.A., Vladimirov, V.L. & Doroschenko, N.V.  (1990)  Aerial
surveys to determine the distribution and number of polar whales and
beluga whales in the Sea of Okhotsk in 1985- 1989.  In: Berzin, A.A.
(ed.), Questions relating to the rational exploitation of marine mammals
in the far eastern seas, pp. 22-34.  TINRO, Vladivostock, USSR Vol 112
[Environment Canada translation 4083779, 109 pp.]
        Bowen, S.L.  (1974)  Possible extinction of the Korean stock of the
gray whale (Eschrichtius robustus).  Journal of Mammalogy 55, 208-209.
        Henderson, D. A.  (1990)  Gray whales and whalers on the China coast in
1869.  Whalewatcher, 24, 14-16.
        Kato, H. and Kasuya, T.  (1997)  Catch history of the Asian
stock of gray whales by modern whaling with some notes on migrations.
Reports of the International Whaling Commission, Special Issue, 17 (in
press).
        Vladimirov, V.L.  (1994)  Recent distribution and abundance level of
whales in Russian far-eastern seas. Russian Journal of Marine Biology,
20, 1-9.