The troubling side of sea turtle recovery

Christi Hughes checks the inside of Boyles the sea turtle’s mouth at the sea turtle hospital at the South Carolina Aquarium in Charleston on Tuesday. Boyles suffers from a old boat strike wound on the top of his shell.

Sea turtle nesting is on track for a record year in South Carolina. So, too, are strandings — turtles found dying or dead.

More than 100 of the animals have been found so far this year, most of them dead, according to the S.C. Department of Natural Resources, closing in already on the annual average of 128 sea turtles found stranded in the state each year since 2000.

The leading cause of stranding is boat strikes, which have killed or injured more than one in every four turtles. The second leading cause is disease, and that is becoming more and more troubling for caregivers and biologists.

The South Carolina Aquarium’s sea turtle rescue program has admitted 24 sick or injured turtles so far in 2015, more than double the number at this time last year, said Kelly Thorvalson, program manager.

The uptick in strandings seems to correlate with studies suggesting there are simply more turtles out there.

“Although it is difficult to say with confidence that we are seeing a recovery in sea turtle populations, it certainly seems that way,” Thorvalson said. “Nest numbers are increasing, in-water sightings are increasing and the numbers of sea turtles that need medical attention are definitely increasing.”

There are seven species of sea turtles found across the world, and all of them are considered endangered or threatened.

Most of the turtles nesting here are loggerheads. The loggerhead, the 300-pound mammoth that is one of the beloved creatures of the Lowcountry coast, lays a few thousand nests here each year.

Green sea turtles also are found here, occasionally the huge leatherback and the Kemp’s ridley, the rarest species.

The turtles remain among the most mysterious of sea creatures. They spend nearly all their life in the ocean and nobody really knows how many are out there.

But only a few hatchlings survive to adults, and adults face natural and man-made threats, including boat strikes, fishing line entanglements and pollution that can cause or worsen health problems.

The Island Turtle Team watching nests and the nesting reptiles on Isle of Palms and Sullivan’s Island has had eight strandings so far this year, said Mary Pringle, a volunteer with the team. That’s actually down a bit from most years, so far. But there’s trouble.

“We’re seeing so many more of the juvenile loggerheads with barnacles and debilitating syndrome,” she said.

Debilitating syndrome is nothing new, but as turtle numbers increase, concern about it heightens. The syndrome is a condition in which turtles show up lethargic and not eating.

“We did get this year a lot more debilitated turtles than we have in the past few years,” Thorvalson said. “If turtle numbers are increasing, we’re just bound to see more sick turtles. What’s concerning right now is we’re seeing more (debilitated) turtles come in with cataracts. That is very serious and very strange.”

National Oceanic and Atmospheric Administration fisheries scientists have been documenting the turtles’ exposure to man-made contaminants that research is suggesting is tied to at least some of the debilitating diseases. Research has shown contaminant releases, particularly in rain runoff, are a problem in the Lowcountry, where they are suspected to cause or contribute to health problems with other sea creatures.

Reach Bo Petersen at 937-5744, @bopete on twitter or Bo Petersen Reporting on Facebook.