Asian sea otters are a subspecies
of sea otter, Enhydra lutris, found off the coasts of the Kuril Islands, the
Kamchatka Peninsula, and the Commander Islands, and which
are occasionally spotted off the coast of Hokkaido, Japan.
This fact sheet will focus only on information related to
this subspecies.
Northern sea
otters share the basic physical characteristics of all
Enhydra lutris sea otters, but they are larger in size
when compared to Northern sea otters, Enhydra lutris kenyoni,
which are in turn larger than Southern sea
otters, Enhydra lutris nereis. Asian sea otters can grow
to 4 feet (1.2 meters), tail included, and weigh up to
80 lbs (36 kg). They have wider skulls and shorter nasal
bones compared to other subspecies (Wilson et al, 1991).
Asian sea otters are said to be less likely to haul out
on land than Northern sea otters (Davis, Lidicker, 1975).
Asian
sea otters were once numerous in their range, which extended
from Hokkaido, in Japan, to the Commander Islands off Kamchatka.
According to Hattori (2005), Asian sea otters had largely
disappeared from Hokkaido even prior to the massive exploitation
of sea otters that took place in the 1700-1800s, as there
are no historical records of Japanese hunting sea otters
in Hokkaido around that time. However, evidence has been
found of sea otters in older Hokkaido archeological sites
(Hattori, 2005).
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| Picture of Asian sea otter, Enhydra lutris lutris, also known as a Russian sea otter or common sea otter, hauled out, endangered, along with the Kuril harbor seals, Phoca vitulina stejnegeri, Cape Erimo, Hokkaido, Japan, Pacific Ocean |
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Kingdom:
Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia/Canoidea
Family: Mustelidae/Mustelids
Genus: Enhydra
Specific: lutris
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Historically, Asian sea otters off the
Russian coast fell victim to the same massive fur trade
exploitation that affected all sea otters in the North
Pacific in the 18th and 19th centuries. Apparently, the
Chinese upper classes had developed an affinity for otter
fur and were willing to pay well for it. Russian trappers
were the first to harvest sea otters in large numbers to
meet Chinese demand, followed by the British and Americans.
Competition for otter pelts was intense, and whenever one
area became depleted, hunters moved on to other areas.
Native populations along the Alaska, Canada, Washington,
and Oregon coasts hunted the animals as well to barter
in trade. By the 1840s, sea otters were virtually extinct
in all areas of their former range.
International protection
of sea otters began in 1911, and sea otters began to increase
in number from their tiny remnant populations. Whereas
it took just 13 years to wipe out Asian sea otters from
the Commander Islands after their discovery in 1741, it
has taken over 250 years for sea otters to repopulate the
islands there to numbers approaching their former density.
There are unconfirmed estimates of 4,000 Asian sea otters
in the Commander Islands today. Good estimates on total
Asian sea otter population are difficult to come by.
Asian
sea otter populations are thought to be increasing in the
Kuril Islands, just north of Hokkaido, Japan. Sightings
of sea otters occasionally occur off the coast of Hokkaido
as well, but these otters are thought to be visitors from
the Kurils, and it is unlikely they will establish permanent
populations in Hokkaido due
to lack of suitable habitat (Hattori, 2005).
The three
subspecies of sea otter, Asian, Northern, and Southern,
have rebounded throughout their range since the fur trade
exploitation era. Of these, the Northern population has
recovered the most, but both the Southern and Northern
populations have experienced periods of setback. In the
late '90s, Southern sea otters experienced a sudden die-off
that remains largely unexplained. Shortly thereafter, Northern
sea otters began disappearing in massive numbers from the
Aleutian Islands, with estimates of 47,000 to 86,000 sea
otter deaths, a decrease of 70% or more. The decrease in
Northern sea otter numbers in the Aleutians has been attributed
to increased predation by orcas (killer whales). Interestingly,
Asian sea otters are thought to have been unaffected, and
numbers appear to have remained stable and may be nearing
capacity.
Existing sea otters are descendants of a small
number of exploitation era survivors. As there is little
genetic diversity among sea otter populations, they are
particularly vulnerable to disease or sudden environmental
change.
Alternate names: Asian Sea Otter, Common Sea Otter
Links to SeaPics.com fact sheets on the other two subspecies
of sea otter:
Northern sea otter (Enhydra lutris kenyoni)
of the Aleutian Islands, mainland Alaska, British Columbia,
Canada and the U.S. State of Washington
Southern sea otter
(Enhydra lutris nereis) of California and Mexico
© Asian
sea otter information assembled from on-line sources by
Kevin
Miller on June 6, 2008 for Seapics.com.
http://www.seaotters.org/theraft/index.cfm?DocID=101
http://online.wr.usgs.gov/calendar/2007.html
http://www.alaskasealife.org/New/research/index.php?page=seaotter.php
http://www.pbs.org/edens/kamchatka/bering.html
http://www.ohs.org/education/oregonhistory/historical_records/dspDocument.cfm?doc_ID=3543B6AB-DFFA-E80F-AB29E62E397577AB
http://www.alaskasealife.org/New/research/index.php?page=seaotter_research.php
http://www.theoceanadventure.com/KIIE/KI5.html
http://www.springerlink.com/content/8261386n13582379/
http://www.jstor.org/pss/1381977 |
