A dead leatherback sea turtle washed ashore on a private beach on the west side of Chappaquiddick last week, the first one found on the Island in 2024.

The turtle, discovered by a homeowner on Sept. 26, was heavily decomposed, said Karen Dourdeville, the sea turtle research coordinator at Mass Audubon. 

The state of the leatherback made it hard to investigate the death, but cuts along the turtle indicate it was killed by a vessel strike, Ms. Dourdeville said Monday. 

The leatherback turtle is one of four species of sea turtles on the waters around the Vineyard. All are federally protected. 

Mass Audubon, a statewide conservation organization, received a call about the turtle from the homeowner. Ms. Dourdeville said. The turtle appeared to be not yet be an adult, but Ms. Dourdeville could not determine the sex due to the advanced decomposition.

Ms. Dourdeville said it is leatherback season and the turtles will be swimming in Vineyard waters until the end of October.

Mass Audubon partners with the Martha’s Vineyard Striped Bass and Bluefish Derby. Reports from fishermen on the water help the organization collect data that helps inform conservation efforts. 

“Fishers are great reporters for us because they’re watching the water,” Ms. Dourdeville said. “...We would love to get sightings of live turtles and dead turtles.”

People who see sea turtles, dead or alive, can report their findings to seaturtlesightings.org or call the sea turtle sightings hotline at 1-888-732-8878.