By Daniel Lovering

CAMBRIDGE, Mass (Reuters) - Marine biologists were trying to determine on Friday what killed at least 10 harbor seals whose carcasses were found this week on beaches in New Hampshire.

Surfers called the New England Aquarium in Boston to report several seal carcasses seen around Jenness State Beach in Rye on Thursday, said Tony LaCasse, a spokesman for the aquarium.

Biologists dispatched to the area found six dead animals, most badly decomposed, and brought two of them to a research center in Massachusetts for an autopsy to check for disease, LaCasse said. Test results could take as long as two weeks, he said.

Two more dead seals were found at nearby Wallis Sands State Beach, while two others were found in the Hampton-Seabrook area, he said.

Other dead harbor seals were reported on the Maine coast on Thursday, he said.

"There's a good chance this could be coincidental," he said, adding that the tide was exceptionally high on Thursday. "That's when we get a lot of carcasses (washing ashore)."

The dead seals may have been part of an apparent harbor seal baby boom this year, LaCasse said. They typically have a mortality rate of 30 percent, and "with a boom there are more pups competing for the same amount of resources," he said.

They also may have been young seals pushed out of their ideal habitat during a migration from the Maine coast to Massachusetts and the eastern tip of Long Island, LaCasse said.

(Editing by Barbara Goldberg and Cynthia Johnston)