FORT MACON — Before you start cursing wintry mixes and the frozen fingers, frosted windshields and slippery roads that accompany them, remind yourself that it could be worse.

You could be a sea turtle.

When water temperatures dip below 50 degrees, the cold-blooded reptiles are susceptible to becoming "cold-stunned," a condition akin to hypothermia that can lead to death.

During the recent cold snap, distressed turtles have been found along the North Carolina coast appearing listless and lethargic. They were scooped up and then warmed up inside the walls of turtle hospitals and aquariums.

On Wednesday, nearly 90 turtles that had recovered from the cold were loaded onto a U.S. Coast Guard cutter and shipped out to sea, to be dropped into the warm waters of the Gulf Stream current.

"These are the lucky ones," said Craig Harms, an N.C. State University veterinarian who accompanied the turtles on their journey.

All species endangered

Like whales, sea turtles have become symbols of both the majesty and fragility of nature. They can weigh hundreds of pounds and range over thousands of miles, yet all seven species of sea turtle are listed under the Endangered Species Act. Their vulnerability inspires people to protect their nests on North Carolina beaches and to help hatchlings make it to the water.

The turtles released Wednesday - greens and loggerheads - set sail from Fort Macon on Bogue Banks. Many of the older turtles had rehabbed at one of the three North Carolina state aquariums, although 56 green turtle hatchlings were rescued from nests in South Carolina and then warmed at the aquarium in Charleston. A few turtles arrived from an aquarium in Virginia Beach, Va.

Getting left behind

Sea turtles generally migrate toward warmer waters when temperatures begin to fall, said state sea turtle biologist Matthew Godfrey. A fraction, because of illness or injury, find themselves swimming in waters that turn cold quickly. But it happens to healthy turtles, too.

"Some of them were just in the wrong place at the wrong time," said Eric Anderson, another NCSU vet.

Then ferry boat captains, beach-goers, park rangers and others find the turtles, in shallow water or washed up on shore. The turtles can appear dead at first, but a quick touch will elicit a reaction, Anderson said.

The cold-stunned turtles are taken to aquariums and animal clinics, where they are checked over and warmed up. Among other ailments, exposure to the cold can lead to bacterial and fungal infections.

Once rescued, the turtles' body temperature is raised slowly. Sometimes the turtles are simply placed in plastic containers and left to come up to room temperature. Gradually, they are reintroduced to water.

Why all the effort?

If the turtles have no other medical issues, they can be sent back to the sea in a few days, Harms said.

A hard-hearted amateur biologist may wonder why the veterinarians and aquarium workers don't leave the turtles alone, and let natural selection take its course. But Godfrey, who works for the N.C. Wildlife Resources Commission, said turtles have a tough go of it already, with pollution, disease, fishing nets, habitat loss and climate change.

"There are so many different threats that affect sea turtles," Godfrey said.

Up until about three years ago, Godfrey saw very few cold-stunned turtles in the winter. But for the last three years or so, at least 65 turtles have been rescued annually. The cause of the increase is not entirely clear, although Godfrey thinks people are becoming more adept at spotting cold-stunned turtles. The wildlife resources commission also promotes a turtle emergency hotline.

Many of these cold-stunned turtles were found by rangers at Cape Lookout and Cape Hatteras national seashores, who search on cold days.

A trip to warm waters

On Wednesday morning, a network of aquarium workers, volunteers, veterinarians and U.S. Coast Guard members came together to send the turtles back home.

Lt. Grant Thomas, commanding officer of the Coast Guard cutter Block Island, planned to take the ship 40 to 50 miles off the coast, looking for water in the 70-degree range. In part, he would depend on information gathered by weather buoys to help decide where to free the turtles.

When not saving turtles, Thomas and his crew enforce fishing laws on commercial boats and provide maritime environmental protection. Returning the turtles is part of that mission, he said.

The turtles arrived in several vehicles, and then were carried in plastic storage containers onto the boat. The temperature outside was 25 degrees.

The containers were stacked in a small hallway where the temperature was in the 60s, a mere preview of the balmy waters ahead.

matt.ehlers@newsobserver.com or 919-829-4889