Island scientists are trying to find out why three loggerhead turtles have been found dead on Vineyard beaches so far this summer. 

The latest dead turtle was found near the land bank entrance of Moshup Beach in Aquinnah on July 10. 

The turtle was retained by the Wampanoag Tribe of Gay Head (Aquinnah) so its shell could be used for traditional and cultural purposes. 

None of the turtles found on the Vineyard had evidence that humans contributed to their death, said Bret Stearns, the indirect services administrator for the Wampanoag Tribe of Gay Head (Aquinnah) natural resources department. He said the reason for their deaths remains a mystery.

“We share the same concern as everybody,” Mr. Stearns said. “We want to know the whole story of how it came to the shore and we want to know the preventative measures we can take.”

The first loggerhead was also found in Aquinnah. On June 17, the natural resources department responded to a call from a beach walker who spotted the first dead turtle near Zack’s Cliffs. 

The second was found just a few days later on June 25 at Lake Tashmoo Town Beach. Staff members at Felix Neck Wildlife Sanctuary assessed the body and buried it onsite.

According to Mass Audubon, 10 loggerheads have been found dead off the coast of the Cape and Islands this summer, including two turtles on Nantucket. 

Loggerheads are one of four species of sea turtles found around the Island. All are federally protected as “endangered” or “threatened."

Andrea Gomez, the public affairs officer for the National Ocean Atmospheric Administration, said it’s normal for sea turtle strandings to occur in Massachusetts this time of year.

“Whenever turtles are in the area, we can have strandings for a variety of reasons. Some human related, such as vessel strikes and fisheries interactions, but some natural such as illness, predation or other reasons,” Ms. Gomez said in an email.

Mass Audubon, the largest nature-based organization in New England, said at least five of the loggerhead turtles died from fatal vessel-strike wounds this summer, although none were found on the Island. The organization is asking that boaters use extreme caution.

If a turtle is found on the shore and appears to be alive, Mr. Stearns said to call the Center for Coastal Studies entanglement hotline at 800-900-3622. From there, a team will collect the turtle, analyze its condition, give it treatment or send it to a larger facility, such as the New England Aquarium, for help.

If a turtle is found dead or alive in the ocean, Mr. Stearns also urged people to call the Mass Audubon sea turtle sighting hotline at 1-888-732-8878. The organization collects data that helps inform conservation efforts.