Sunday, September 1, 2013

Sea otter Distribution, Status and Taxonomy

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Sea otters, originally native to Japan, Alaska, Canada, Russia, Mexico and the United States, now have established populations in southern California, Washington state, British Columbia, Alaska and the east coast of Russia.  Recently, there have been sporadic sightings along the Oregon coast seeming to indicate the species is attempting to expand southward.

The sea otter is classified by the IUCN as endangered with a decreasing population, one that is that is believed to have declined over 50% in the last 30 years, equating to about three generations.  Their populations, once numbering 150,000 to 300,000 animals worldwide, decreased to approximately 2,000 when the commercial fur trade ended in 1911. 

Sea otter range map courtesy of www.iucnredlist.org

Sea otters have many threats in the modern day. Their greatest threats are from oil spills, either small or large like the Exxon Valdez catastrophe of 1989, pollution in their native habitats and the resulting diseases, conflicts arising from commercial fisheries, as well as boat strikes.  There has been an increase in orca and shark predation in recent years.

The taxonomic listing for the sea otter is as follows: Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Mammalia; Order: Carnivora, Family: Mustelidae; Subfamily: Lutrinae; Genus: Enhydra; Species: Lutris.  The sea otter is further divided into three subspecies, depending on its range.  Enhydra lutris lutris ranges from the Kuril Islands north past the Kamchatka Peninsula to the Commander Islands in the Western Pacific, Enhydra lutris kenyoni’s range is on the eastern side of the Pacific in the Aleutian Islands and Alaska. Finally, Enhydra lutris nereis inhabits the central coast of California.