PDF/Print Version

NMFS Northeast Regional Office

N         E         W         S

Unusual Mortality of Harbor Seals Continues off Maine

Portland, Maine -- A team of seal stranding experts led by Marine Animal Lifeline (MAL) of Portland, Maine has examined 27 harbor seals found dead on Stratton Island in Saco Bay. Officials with NOAA’s National Marine Fisheries Service (NOAA Fisheries) said today that the seal deaths are under investigation as part of an ongoing unusual morality event involving harbor seals in coastal Maine.

NOAA Fisheries is the federal agency charged with protecting the nation’s seal populations, and whose authorities govern investigation of unusual mortality events such as these. Marine Animal Lifeline is a private nonprofit organization authorized by NOAA Fisheries to respond to stranded seals in southern Maine.

“Last year, NOAA began to investigate the high numbers of harbor seals stranding dead along Maine’s coast from Pemaquid to Saco,” said Greg Early, onsite coordinator for NOAA Fisheries in response to this unusual mortality event. “The Stratton Island event is similar enough to that situation-- the same time of year, mostly adults in good body condition—that it may very well be related.”

Greg Jakush, president of MAL, said today that his group will continue to monitor the island for the near future, in addition to its stranding response and rehabilitation work. “We need to know if this is a single event or something that is continuing to occur, and if it is somehow related to this haul-out area,” he said. “If more deaths occur we may be able to get better samples to help us figure out what may be killing these seals.”

On August 17, 14 seal carcasses were reported to the Marine Animal Lifeline by the Maine Audubon Society, which staffs Stratton Island during the summer to monitor the local tern population. A team from MAL immediately responded to the report, and made initial observations of the carcasses, all of which were in advanced stages of decomposition.

A team of experts was convened by NOAA Fisheries to review the information gathered, and to work with MAL to devise a plan for thorough documentation and sampling of the carcasses. Marine Animal Lifeline assembled a field team including MAL staff and volunteers, and specialists from Allied Whale, the Maine organization located in Bar Harbor and authorized by NOAA Fisheries to respond to marine mammal strandings in northern Maine. The field team spent most of Friday, August 20, on the island conducting necropsies and taking samples from 27 dead harbor seals found in close proximity to one another on the island. All but two animals were adults.

Jakush said that all of the animals were in advanced stages of decomposition, and that there were no obvious signs of physical trauma. A few biological samples were obtained that could point to a cause of death. Heads were also collected, which can be examined to confirm the species and establish age. Biological samples from the Stratton Island animals, as well as from some similar seals that stranded elsewhere in Maine this year, will be examined under laboratory conditions for indicators of what might have caused the deaths or what the animals may have had in common.

This unusual mortality event dates from 2003, when 66 adult harbor seals were found dead from the midcoast to southern Maine, most during September through November, and all some weeks after they died. Those deaths were related to one another owing to the size and overall condition of the carcasses, in addition to the numbers being about twice what would be expected for observed deaths during that time of year. Samples from those carcasses produced no conclusive results pinpointing cause of death.

A panel of experts established under the U.S. Marine Mammal Protection Act to advise the Federal government on marine mammal health concerns has determined that the situation is best investigated as a continuation of the 2003 unusual mortality event. This designation allows use of a contingency fund to further investigate the cause of the deaths, and makes it easier for the agency to call on a wider pool of experts for assistance.

Reports of stranded seals, seen dead or alive south of Rockland, can be made to Marine Animal Lifeline at 207-851-6625. North of Rockland, call Allied Whale at 207-288-5644. If you have information about anyone intentionally harming or harassing seals or other marine mammals, call the NOAA Fisheries Enforcement hotline at 800-853-1964. All calls to the enforcement hotline are confidential.

Harbor seal carcasses marked for necropsy and tracking on Stratton Island
Photo courtesy Marine Animal Lifeline

- ### -