Seal deaths stump scientists

December 23rd 2:37 pm | Carey Restino    

Scientists are still stumped as to what is causing ringed seals and walruses in Northwest Alaska to be afflicted with lesions, become lethargic, and in many cases, die. On Tuesday, the National Oceanic and Atmospheric Administration announced it had declared the die-off an "unusual mortality event," opening the door to more study and inves- tigation into the cause.

"Alaska coastal communities depend on ringed seals for food," said Julie Speegle, a NOAA public affairs officer. "There has been a great deal of concern about this event."

Samples taken from the seals were sent off for testing to numerous laboratories last fall, but screening for 18 known pathogens has come back negative, scientists reported during a teleconference on the topic. While no reports of the affliction passing to humans or pets have been reported, hunters are being advised to use traditional and customary safe handling practices and fully cook all meat as well as wash hands and bleach equipment that may have come in contact with a diseased animal.

According to a release, testing is continu- ing on the animals looking at numerous factors that may be responsible for the seal affliction. Everything from stressors relating to sea ice changes to radiation exposure and immune-system diseases are being considered, the report said.

Since mid-July, some 60 dead and 75 diseased seals have been reported in Alaska. Reports continue to come in from the Bering Straight region as harvesting continues in that area. In addition, skin lesions have been seen on walruses near Point Lay, where a haul-out of some 20,000 animals was stud- ied this fall. Scientists studying the walruses, however, reported relatively low mortality rates, despite observing many animals with the lesions.

Necropsies and lab tests have found lesions, fluid in the lungs white spots on the liver and abnormal brain growths, the release said. Some animals were found with smaller-than-usual lymph nodes, which could indicate that the animal's immune system was compromised.

The abnormal lesions do not appear to be isolated to Alaska. Seals and walruses in Canada and Russia have also been noted with similar symptoms.

"While it is not clear if the disease events are related, the timing and location of the disease suggests the possibility of transmission between the populations, or shared exposure to an environmental cause," the release said.

A working group has been formed to study the event, and last week recommended to NOAA and the National Fish and Wildlife Service that the agencies declare an unusual mortality event. The Fish and Wildlife Service had not immediately made such a declaration, though one was expected, Speegle said.

Anyone encountering a sick seal or walrus, especially one that is unusually approachable, is encouraged to avoid making contact with the animal. Sick or dead animals can be reported to the following agencies:

* North Slope area: North Slope Borough Department of Wildlife Management: 907- 852-0350

* Bering Strait region: Alaska Sea Grant Marine Advisory Program: 1-800-478-2202 or 907-443-2397

* Elsewhere in Alaska: NOAA Fisheries Alaska marine mammal stranding hotline: 1-877-925-7773

 

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