14 March 2013


Healthy ringed seal in snow. Credit ilovegreenland via Flickr.
In the summer of 2011 indigenous hunters in the Alaskan Arctic began to find sick and dying seals covered in oozing sores and losing hair. That year more than 200 ice seals (ringed, bearded, and spotted) were found in Alaska, Canada, Russia, and Japan suffering from  unusual hair loss, delayed molt, skin lesions, and lethargy. Some Alaskan walruses showed similar symptoms. NOAA declared an unexplained mortality event (UME) and began to investigate the causes. In 2012 Alaskan polar bears were found with  hair loss, inflamed and crusting skin, and oral lesions. NOAA has not yet declared a UME for them.

No official explanation has been determined for the seal and walrus ailments. But now the Alaska Dispatch reports that Bruce Wright, senior scientist with the Aleutian Pribilof Islands Association, thinks sunburn might be the cause. And not just any sunburn, but sunburn caused by the anomalously huge ozone hole in 2011. I reported on that in my last post here. From the Alaska Dispatch:
Wright isn't suggesting all symptoms uncovered during necropsies of the affected seals are [sunburn] related. Some of the animals were found to also have bleeding and swelling in their lungs, livers, lymph nodes and other internal organs.... Wright questions the interrelatedness of multiple stressors, including sun and UV radiation exposure, and other illness or nutritional deficiencies on the overall health of the animals. He plans to present his theory in May at a science conference in Russia. “It all just made sense to me. I have just been baffled that nobody else has proposed this (sunburn) hypothesis,” he said.
Ringed seal with sores on head and face. Credit: NOAA / North Slope Borough Department of Wildlife Management staff
Among the other possibilities that other researchers are investigating:
  1. Is some illness in the body producing light-sensitive blood chemicals, similar to hepatitis?
  2. Are the large algal blooms in Kotzebue Sound / Chukchi Sea that began in 2009 triggering a chemical reaction that triggers photo-sensitivity?
  3. Is exposure to Japan's 2011 Fukushima nuclear plant accident involved?
The real cause may never be known since cases have now tapered off. As has the ozone hole.
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