BOSTON (AP) – Eighteen Atlantic white-sided dolphins have been found stranded on Massachusetts beaches in recent days, ever since a violent storm lashed the coast late last week, a spokesman for the New England Aquarium said Tuesday.

Most of the strandings occurred in Wellfleet, Orleans and Brewster on Cape Cod, but strandings have also occurred on Martha’s Vineyard and in Nahant, just north of Boston, Tony LaCasse said.

Fourteen of the marine mammals died, but four were taken to the Mystic Aquarium in Mystic, Conn. for rehabilitation, LaCasse said. Two dolphins found in Orleans on Sunday, and two found in Wellfleet on Monday were taken to Mystic.

They will be kept there until they are well enough to be released, which could take several months, LaCasse said.

The animals could not be taken to the New England Aquarium in Boston because its rehab tanks are currently occupied by sea turtles.

The Atlantic white-sided dolphin is not an endangered or threatened species, LaCasse said. They can grow from 61/2 to 9 feet in length and weigh from 300 to 500 pounds as adults. They are native to New England waters but can be found in waters from Virginia to the Canadian Maritimes.

It is not known exactly why the dolphins are being stranded, but they often get stranded after severe storms like last Friday’s nor’easter, LaCasse said.

Anyone who sees a stranded dolphin should call the stranding hotline at 617-973-5247.