SOUTH PADRE ISLAND - A marine life rehabilitation organization has opened an investigation following the discovery of several dead sea turtles in Boca Chica Beach.

Sea Turtle Inc. said nine green sea turtles washed up on shore on Wednesday. They said there is little evidence to how they may have died.

Sea Turtle Inc. executive director Jeff George said the sea turtles’ carcasses are being preserved. They will be picked up by federal researchers and taken to a Corpus Christi lab for additional testing.

George said the protected green sea turtle has gone from an endangered species to a threatened species.

“It is a blow. Our hearts are broken by it, because we’re in the business of helping turtles,” he said.

George said there were no real apparent signs of damage to their bodies. He said there wasn’t a significant cold front forecasted either.  

“Turtles don’t drown from weather in the Gulf of Mexico. In the Laguna maybe, but not the Gulf,” he said.

The expert said he considers the deaths suspicious. He said there is some evidence that shows the turtles may have drowned.

George said the animals are expert swimmers that can hold their breath underwater for 20 minutes. He suspects it was something that held them down.

“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 said.

Texas Parks and Wildlife Sgt. Jared Barker said they will be performing a necropsy on each turtle to determine how they died.

 “There could be some illegal gillnets that are being used in Mexican waters where they are allowed to fish with those types of nets,” he said.

Barker added the U.S. has a treaty with Mexico to protect certain animals, including sea turtles.

“The turtles are getting entangled in those nets. As the fishermen collect their harvest out of the nets, the turtles are not something they are able to utilize, so they throw them back in the water and they drift north into the United States,” he said.

George said besides the cluster of nine turtles, another 15 turtles have also been found dead in the past three days. Four of those were discovered as we worked on the story.

NOAA researchers said they will perform necropsies to determine the turtles’ cause of death.

George said they find anywhere from 100 to 150 dead sea turtles in South Padre Island, Laguna Madre and Boca Chica Beach area every year. He said the type of findings like on Wednesday are highly unusual.

It is illegal for anyone to take a sea turtle dead or alive from their habitat.