By Jason McLure
LITTLETON, New Hampshire (Reuters) - Federal officials have joined an investigation into the mysterious deaths of young harbor seals, as the number of dead seals discovered on beaches across three states in New England rose to 49.
Seals began washing up on the beaches of northern Massachusetts, New Hampshire and southern Maine last week, said Maggie Mooney-Seus, a spokeswoman for the National Oceanic and Atmospheric Administration's office in Gloucester, Massachusetts.
"Some of them have been decomposed," she told Reuters on Wednesday. "We're hoping we're not going to see a lot more. We don't know at this point what's caused it."
The densest cluster of seal deaths has been along New Hampshire's 18-mile coast, where 17 seal carcasses have been recovered since Friday, said Tony Lacasse, a spokesman for the New England Aquarium in Boston.
The aquarium has conducted autopsies on three of the least-decomposed seals and found that they all had an adequate layer of blubber to survive.
That suggests the young seals did not die because of a failure to develop hunting skills, which causes the natural deaths of about 30 percent of harbor seals after they are weaned from their mother, Lecasse said.
"The results were a little surprising to us," Lecasse said. "We're doing tissue sampling and have sent those out to labs across the country."
Results are expected next week, and could indicate whether seals died because of disease, toxins or another cause, he said.
Massachusetts, New Hampshire and Maine are home to large populations of harbor seals, which occasionally draw great white sharks and other predators to their breeding grounds.
(Editing by Barbara Goldberg and Greg McCune)