SOUTH PADRE ISLAND - Multiple news sources, including the Valley Morning Star, are reporting that 15 dead green sea turtles washed ashore in December on Texas’s South Padre Island at Boca Chica Beach and Isla Blanca Beach.

The Valley Morning Star reports that roughly 100 to 150 dead sea turtles are found in the South Padre Island, Laguna Madre and Boca Chica Beach area every year. To find 15, over a period of three to four days, is unusual, local officials say.

The sea turtle rescue and rehabilitation group Sea Turtle Inc. reports that the sea turtles’ carcasses have been preserved. They were picked up by federal researchers and taken to a lab in Corpus Christi, Texas, for additional testing.

“Our hearts are broken by it, because we’re in the business of helping turtles,” Sea Turtle Inc. executive director Jeff George told the Valley Morning Star.

Watch a video of green sea turtles in Hawaii.

George said he does not believe the turtles died due to prolonged exposure to cold water and that he considers the deaths suspicious. He said there is some evidence that shows the turtles drowned.

“If these turtles were caught in a fishing net or perhaps an illegal gillnetter or something offshore, within a matter of 20 minutes they would have drowned,” he told the Valley Morning Star.

Texas Parks and Wildlife says NOAA researchers will be performing a necropsy on each turtle to determine how they died.

It is illegal for anyone to take a sea turtle dead or alive from their habitat. South Texas inshore waters provide very important habitat for green sea turtles (Chelonia mydas).

Learn 7 interesting facts about green sea turtles!