The Plight of the Walrus

This photo was provided by the North Slope Borough Department of Wildlife Management.  The well-being of walrus is threatened not by a pathogen but by the very real loss of sea ice that is forcing them to swim greater distances to find ice that is appropriate for hauling out and resting.  The overall health of the walruses that I have examined both grossly and histologically has been excellent.

This past summer I was able to collect tissues from 3 subsistence-harvested walruses.  It is more often the case that the hunter will butcher the walrus on a suitable piece of ice, leaving the visceral organs behind and returning with the skin, blubber and meat.  It is so difficult to haul the entire carcass back to town to butcher.  One of the hunters was kind enough to bring the entire carcass back for me to examine.  I was so grateful to the hunter for doing so, as I have never been able to examine all of the visceral organs before!  He was able to do so because it was a young healthy male.

Walrus Lungs

Note the size of the trachea and principal bronchi!

Some hunters eat the heart-the hunter was kind enough to let me take a piece of the heart.  Note the abundant pericardial fat!

The liver and gall bladder

Clean, healthy abdominal viscera with minimal gross postmortem change

Check out the thickness of the diaphragm!

Spleen

An empty walrus stomach.  Generally I find clams inside the stomach of the walrus.  People will save these clams and make clam chowder with them.  However there are walruses that are seal eaters, meaning they will eat ringed seals.  This practice may account for previous cases of Trichinosis in people who have consumed uncooked walrus meat.  Graduate student Jill Seymour (UAF) has been collecting tissues from subsistence-harvested walruses on the North Slope and St. Lawrence Island to determine the prevalence of Trichinella spp.

Walruses are highly dependent upon ice substrates for reproduction, calving and resting.  Walruses have been forced to change their behaviors in response to selection pressures exerted by a changing Arctic marine environment.  In the fall of 2007, large scale walrus haulouts were noted for the first time ever on the Alaskan shores of the Chukchi Sea from Peard Bay to Cape Lisburne.  On September 14, 2009, USGS scientists discovered fresh carcasses of young walruses dispersed along the sandy beaches at Wainwright extending south to Icy Cape.  The scientists documented the presence of 131 carcasses-most were young based on photodocumentation and examination of 12 of the carcasses.  There is speculation that loss of sea ice was ultimately responsible for exhaustion, trampling and separation of calves from their mothers-the result was the largest walrus mortality event recorded on Alaskan shores of the Chukchi Sea.

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