
Diseased Ice Seals and Unusual Mortality Events
UMEs for ice seals in the Bering and Chukchi Seas of Alaska.
2018–2020 Unusual Mortality Event
Since June 1, 2018, elevated ice seal strandings have occurred in the Bering and Chukchi seas in Alaska. This event has been declared an Unusual Mortality Event (UME).
Learn more about the 2018–2020 ice seal UME
2011–2016 Unusual Mortality Event

This UME occurred from May 1, 2011 to December 31, 2016, involving primarily ice seals including ringed seal (Pusa hispida), bearded seal (Erignathus barbatus), ribbon seal (Histriophoca fasciata), and spotted seals (Phoca largha) in northern and western Alaska. The minimum estimate of the total number of impacted seals was 657 seals, which included 233 dead stranded seals, 179 subsistence hunted seals, and 245 live seals that stranded or were sampled during permitted health assessments studies. The investigation identified that clinical signs were likely due to an abnormality of the molt, but a definitive cause for the abnormal molt and the UME was not determined.
Disease Fact Sheets
- June 2016 Update to the 2011 Arctic Pinniped UME (PDF, 1 page)
- May 2014 Update to the 2011 Northern Pinnipeds UME (PDF, 3 pages)
- February 2014 Update to the July 2011 Northern Pinnipeds UME (PDF, 2 pages)
- March 2012 Update to Northern Pinnipeds (Ice Seals & Walruses) UMEs (PDF, 3 pages)
- November 22, 2011 Update on Investigation and Findings for Arctic Seal Disease Outbreak (PDF, 4 pages)
- November 10, 2011 Update: 2011 Arctic Seal Disease Outbreak Fact Sheet (PDF, 4 pages)
Disease Outbreak Flyers

- Unusual Mortality Event
- Update, March/April 2013
- Questions and Answers, June 2012
- Investigations and Findings, February 2012
- Preliminary Assessment of Radionuclide Exposure
- Public Health Guidance for Contact with Marine Mammals
- Bering Strait Region Disease Flier, Sea Grant Marine Advisory Program, November 2011
- Arctic Region Disease Flier, North Slope Borough, August 2011
More Information
