Deaths of harbor seals alarm officials
The number of harbor seals found dead on beaches from Massachusetts to Maine has spiked in recent weeks, alarming authorities who are searching for possible causes.
Between Sept. 1 and this week, federal officials have counted 94 dead harbor seals between Cape Ann and Cape Elizabeth, more than three times the number of dead seals found during September and October in each of the last two years.
“This is definitely concerning,’’ said Tony LaCasse, a spokesman for the New England Aquarium, which is investigating the deaths. “This is an exceptional event.’’
Last year, the National Oceanic and Atmospheric Administration recorded 30 dead harbor seals in September and October. During the same period, agency officials said 25 had been found dead in 2009 and 72 in 2008.
There are no recent estimates for the size of the local seal population. In 2001, NOAA estimated there were about 100,000 harbor seals in waters off New England, and most scientists think that number has increased substantially since then.
“With a higher population, we expect to see more deaths, but this is higher for the population,’’ said Maggie Mooney-Seus, a NOAA spokeswoman.
She said that most of the dead seals were born a few months ago and that it is typical for pups to be found dead this time of year. The pups typically nurse for about a month and then must fend for themselves.
On average, 30 percent of newly born harbor seals die every year, LaCasse said.
“We do see a lot of this, but this is more than we expect to see,’’ he said.
The New England Aquarium is conducting necropsies on three carcasses it recovered. Initial results found they had “adequate blubber layer,’’ suggesting they had no problems feeding and probably died for another reason, LaCasse said.
“We’re looking for other causes, such as an underlying disease,’’ he said.
The results of their tests, he said, were delayed because the pathologists have been responding to a “critical mortality event’’ for killer whales in Alaska.
In addition to the seals, two dead pilot whales were discovered this week along the Massachusetts coast.