The mysteries behind what made Alaska seals and walrus sick last year and caused bald spots on polar bears this spring largely remain unanswered.
"We do not yet know the cause," NOAA spokesperson Julie Speegle said via email. The event now includes all four species of ice seals (spotted, bearded, ring and ribbon) and Pacific walrus. "We hope to find out what it is."
Alaska Native hunters who rely on the animals for food, clothing and to make artwork and handicrafts find the lack of answers unsettling. Bird flu and other flus have been ruled out, as have a host of other known viruses.
Some suggest that the seals may have come into contact with an ocean pollutant, perhaps from a waste-dumping ship. Goodman said he doesn't believe the ocean is polluted, but thinks a one-time exposure from a single ship is plausible. It would also explain, he said, the hair loss that polar bears were found to have this year, much of it near the head and neck. If they were swimming, that's where they'd come into contact with it, he theorized.
As researchers continue looking, they’re also awaiting the results of more in-depth radiation testing (in February, NOAA said early tests showed contamination from Japan's Fukoshima power plant disaster was an unlikely cause) and are looking at the ocean environment for possible clues. Water temperature, sea ice condition, ocean salinity and pH, in addition to food sources, are aspects of the seals' marine ecosystem that are also under investigation.
"At this point we are thinking it may be a combination of factors," Speegle said. The theory is, something is weakening the animals' immune systems and in a more weakened state they are more susceptible to illness.
An updated report from NOAA is due out at end of the week.
RADIATION (Radionuclides): Currently, preliminary results confirm cesium 137 levels in one healthy and four UME seals are similar to cesium 137 levels in Alaskan seals sampled during the mid – 1990’s. Testing of the remaining three seal samples for gamma analysis is ongoing. Muscle tissue sampling and analyses for UME and healthy seals will continue during 2013.
Have ice seals or walruses been affected by UME symptoms during 2013?
No UME ice seal or walrus cases have been reported to date in 2013. Seals harvested near Point Lay and Barrow this winter appear to be robust, healthy, and without evidence of infection (Fig. 1). Although still early in the year, there have been no reports of UME seals from the Bering Strait region, and neither Russia nor Canada has reported sick seals.
Researchers: Skin ulcers on Alaska wildlife after Fukushima were never observed before — Also reported in seals from Japan — We couldn’t document fallout pattern when plumes hit and animals were on the ice
Doug Dasher, University of Alaska Fairbanks, Nov. 6, 2013 (at 10:00 in): We also worked with the North Slope Borough on the Unusual Mortality Event with the ringed seals. [...] We didn’t see any radiation levels in the seal tissues that would indicate levels of radiation that should have caused the lesions and illnesses that they saw on the seals, but we couldn’t document what the fallout pattern would have been at this time the seals were on the ice when the Fukushima plumes were passing that area. Nor to my knowledge has there been any definitive virus or otherwise defined as to what exactly affected the seals at that time.