Local biologists aren't sure exactly what killed , but one thing that they are sure of is that neither one was the sea turtle that the Coast Guard helped free just days earlier.
Kim Durham, the rescue program coordinator at the , said that both carcasses were so badly decomposed that she's confident could not be one in the same even if it did die after it swam off.
In fact, she said only the sea turtle found in East Hampton Village on Friday morning was a leatherback. The second dead turtle, found in Napeague State Park later on Friday, was a loggerhead sea turtle.
Loggerheads are listed as a threatened species, as opposed to leatherbacks, which are endangered species.
Police discovered the dead leatherback, which was headless, about 20 feet from the jetty on and contacted the Riverhead Foundation. Due to its size — it was about 4 feet long — and location, foundation biologists decided to leave the carcass and just take a genetic sample, as well as photo documentation, to send onto the National Oceanic and Atmospheric Administration.
Durham believes it was either a sub-adult or an adult, based on size. She could not determine, however, its sex based on the pictures taken. She said there were no obvious signs of sharp force trauma, such as from a boat's propeller, and it was not clear why the head was missing.
The smaller loggerhead, picked up in the state park, was brought back to the aquarium for a full necropsy, which was completed on Monday. Durham said it was a female juvenile sea turtle, about 3 1/2 feet long, that also showed no trauma, though she said the condition of the carcass was limiting. No cause of death was determined.
Durham said that there's no cause for alarm that two sea turtles were found dead on the same day. "This is the season we do recover them," she said. "If the current is going the right way, we see an increase of carcasses."
In fact, the Riverhead Foundation responds to 40 to 60 reports of sea turtles per year. So far in 2012, 19 dead sea turtles have been logged.
The more jelly fish in the water, the closer the sea turtles come to the shoreline, Durham said. It's also common for them to get entangled in the lead line from lobster traps, like the one the rescued off Montauk on July 11.
From photographs, Durham believes it was a female adult leatherback weighing about 800 pounds and 6 1/2 feet long.
"There's no doubt the Coast Guard saved that animal's life," Durham said.
Photos show the line was wrapped around the sea turtle's neck twice and around both fins four times. She said that turtle has "significant scarring around the neck and foreflippers." However, she thinks the turtle will survive the injury. "These guys can take a significant amount of damage and still survive."