A large dead leatherback turtle that was more than five and a half feet long washed up at Great Rock Bight beach on the north shore last Tuesday afternoon. The beach is owned by the Martha’s Vineyard Land Bank. Land bank property foreman Matthew N. Dix said the New England Aquarium was contacted, but then the turtle washed back out into the Sound.

Mr. Dix speculated that the turtle may have been killed by a boat, as it had large gashes on it that could have come from a propeller.

Leatherback sea turtles are seen occasionally in waters around the Vineyard. They are more often seen in the summer, but can also adjust to the colder water temperatures in winter. The animals feed on jellyfish. They are seen by boaters traveling Vineyard and Nantucket Sounds.

This is the time of year when marine mammal strandings become more common on the Cape and Islands. On Sunday, six Atlantic dolphins stranded on a beach in Wellfleet. As of yesterday, two had died, according to reports. The four that survived were moved to Provincetown and released into deeper water.

On Saturday, August 11, Oak Bluffs shellfish constable David Grunden did a necropsy on a pygmy false killer whale that was discovered at Norton Point beach. Mr. Grunden is a member of the Vineyard’s marine mammal stranding network. He said the animal measured seven feet in length. The New England Aquarium was notified in this case as well.

He said this animal’s northern range is usually Chesapeake Bay, but it is not unheard of to see them this far north. Mr. Grunden said there was no apparent cause of death, but that he observed the animal hadn’t been eating for a while.

Mr. Grunden said if anyone sees a marine animal in distress they should call the New England Aquarium rescue hotline at 617-973-5247.