Dead leatherback turtle beaches in Oak Bluffs

Mass Audubon and Derby officials hope to minimize turtle strikes through new initiative.

A leatherback sea turtle slain by a boat propeller washed ashore in Harthaven recently. —Brittany Bowker

A leatherback turtle has washed up in Harthaven, done in by a propeller strike that cut it almost in two. The largest species of sea turtle in the world, the leatherback is a jellyfish eater seasonally found in Vineyard waters. Jellyfish stings and sightings have been numerous in recent weeks.

“They follow the jellies,” Karen Dourdeville, a Mass Audubon sea turtle researcher, told The Times. This includes other “gelatinous organisms” similar to jellyfish, she said.

Dourdeville examined the Harthaven turtle carcass last week and determined it was an adult female leatherback turtle.

“The boater that hit it reported it,” she said. It was struck on August 16, “five miles northeast of where it came ashore in Harthaven.”

“Vessel strikes and entanglement in fixed, vertical-line fishing gear are two leading causes of death and injury to sea turtles,” according to a press release from Mass Audubon and the Martha’s Vineyard Striped Bass and Bluefish Derby, which are co-sponsoring a turtle-spotting campaign during this year’s Derby. The Derby is scheduled from Sunday, Sept. 9, through Saturday, Oct. 13.

During the tournament, anglers will be asked to report any sightings of not only leatherbacks, but Kemp’s ridley, loggerhead, and green sea turtles, all of which are listed as federally endangered.

“We’re excited to be involved,” Derby chairman Joe El-Deiry said.

Boaters in the Derby or those just cruising local waters can report turtle sightings at or via hotline: 888-SEA-TURT.

El-Deiry said the Derby boasts 3,400 to 3,500 participants. “So that’s a lot of pairs of eyes,” he said.

Fairly small props “can do a great deal of damage,” Dourdeville said. “Their upper shell is sort of made up of a lot of tiny shells that make up a mosaic.” The whole is not rigid, like other sea turtle shells, she said.

A special characteristic of leatherbacks is the ability to withstand colder water. In what would seem very a un-reptilelike ability, they can raise their internal temperature, she said, and often venture to Newfoundland to feed.

Many strikes could be avoided by boaters paying closer attention to the water in front of their boat and the disuse of autopilot features.

“We get many reports of boaters who say, I would have hit it had I not been looking ahead,” she said. “We’re not trying to blame boaters; we’re trying to partner with boaters.”

To would-be turtle shell filchers, Suzan Bellincampi, director of Mass Audubon’s Felix Neck Wildlife Sanctuary, warned it’s a federal offense to take any part of the turtle in Harthaven, or any sea turtle.

Dourdeville said the decaying turtle was marked with bright paint to indicate it’s been examined. This helps both the public and researchers stay on top of what has or hasn’t been logged and looked at officially. Sometimes dead turtles can refloat, too, she said, and the paint keeps the turtle from appearing to be a new fatality.

Even if somebody was game to break the law, Dourdeville said, the turtle is so rank nobody would want to come near it. Moreover, it appears to weigh 800 pounds, and its shell, being so different from other turtle shells, will likely fall apart as the creature breaks down.

Folks have reported birds scavenging from the turtle, Dourdeville said, but as it becomes increasingly fetid, gulls, in her experience, lose their appetite, and only turkey vultures can stomach the meal.