According to the Alaska Dispatch, since mid-July, more than 60 dead and 75 diseased seals have been found with skin lesions and hair loss in the Arctic and Bering Strait regions of Alaska. In addition, scientists with the U.S. Fish and Wildlife Service reported several diseased and dead walruses in their fall survey this year, and the walruses were also found with skin sores and patchy hair loss.
Scientific studies have indicated that a virus is not responsible for the disease impacting these animals, but scientists have been unable to isolate a single cause. Tissue samples from the affected animals have been screened for a variety of pathogens, but all of the results so far have been negative.
NOAA declared mysterious seal deaths "an unusual mortality event"
The seal deaths have been declared "an unusual mortality event" by the National Oceanic and Atmospheric Administration (NOAA) , a status that provides additional resources to investigate the cause. The U.S. Fish and Wildlife Service is considering making a similar declaration for the Pacific walrus.
Seal tissue samples will be tested
Tissue samples will be examined for various factors including signs of immune system diseases, fungi, toxins, contaminants related to sea ice change, and radiation. Some of the seals and walruses have undersized lymph nodes, possibly a sign of weakened immune systems. The results of these tests will not be available for several weeks.
Concerns that the seal deaths may be linked to Fukushima radiation
Local communities have been concerned that the marine mammals deaths may be due to a causal relationship linked to the Fukushima nuclear plant's damage.
Scientists at the Institute of Marine Sciences at UAF believe it's unlikely that Fukushima was the cause of the seals' deaths, given that levels of detected radiation are relatively low around Alaska. Water tests have not shown evidence of elevated radiation in U.S. Pacific waters since the March earthquake and tsunami in Japan. If there is a link to Fukushima, the researchers will find it, as they will be testing for radionuclide Cs-134 and Cs-137.
The disease hasn't spread to polar bears or humans, may have spread to other arctic seals
It is not known whether the disease can be transmitted to humans or other animals. Polar bears, which prey on ringed seals, have not shown symptoms of the disease. Humans have also not shown symptoms of the disease. Similar symptoms have been reported in ringed seals in Russia and Canada. It is not yet determined if the causes are related. However, the timing and overall location of the disease suggests the possibility of transmission between the Alaskan and Russian populations, or at least a shared exposure to an environmental cause.
The public are encouraged to report sightings of diseased or dead animals. NOAA’s Alaska regional fisheries website has more in-depth information about this disease outbreak in ringed seals and walruses.