CAN SEA TURTLES GET TOO COLD DURING THE WINTER IN NORTH CAROLINA?

 

With colder months moving in, changing water temperatures off the coast of North Carolina pose a threat to sea turtles who live off the coast of the Tar Heel state. Cold shock, also known as cold stun, is a condition that affects sea turtles and causes them to become very weak and unable to swim.

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What kind of sea turtles live off the coast of North Carolina?

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There are three to five species of sea turtle that are found off the coast of North Carolina.  The ones commonly found are loggerheads  (which feed and nest here), green sea turtles (which rarely nest but as juveniles are coming into the sounds to feed) and the Kemp’s Ridley (which almost never nest here but are very common in the summertime for growing and maturing).

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What is cold shock?

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Cold shock is basically hypothermia in sea turtles, so they get too cold for them to operate.  Sea turtles are cold-blooded, which is an advantage since they can operate at several different body temperatures without expending a lot of extra energy to maintain their metabolic rate. But at some point, it gets too cold for their cells to operate efficiently, and they just shut down.”

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That’s when the cold shock sets in, which normally happens when the water temperature is around 53 to 59 degrees Fahrenheit. If the water temperature drops rapidly, like it does in the shallow waters in the sounds of North Carolina, the turtles are more likely to develop cold shock at a slightly higher temperature than they otherwise would.

 

What happens to a turtle when it has cold shock?

 

Sea turtles can’t stop cold shock from happening when the process starts, so how does the condition really affect the animal?

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When sea turtles get cold stun they shut down.  Fortunately, their reflexes are good, and they can grab a lung-full of air so that they float on the surface of the water. They also can lift their head above the surface as the last reflex before they are completely stuck, which helps for breathing.

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These reflexes help with the rewarming process, because if the turtle stays on the surface of the water they are in direct sunlight. Even if the water is cold, if the sun comes out the turtles have a chance to warm up and hopefully swim toward warmer waters.

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How do veterinarians treat cold shocked turtles?

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The first step is getting the turtles from the beach to the treatment facilities, which include CMAST, the Karen Beasley Sea Turtle Rescue and Rehabilitation Center, and the Sea Turtle Assistance and Rehabilitation (STAR) Center on Roanoke Island.

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It’s important not to warm the turtles up too fast. When that happens, a reperfusion injury might occur which is when the affected tissue suddenly gets circulation quickly and this can cause problems.

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When the turtles make it to the facility the veterinary teams start the turtles close to the temperature they are at when they arrive, so that the turtles do not heat up too quickly. When cold shock occurs, these are typically “mass casualty events, which means there can be 50 or more turtles at once, so the doctors split the animals up into treatment groups.

 

There are two different types of cold shock: acute cold shock and chronic cold shock. Acute cold shock sea turtles are the ones who are otherwise healthy and doing great and don’t need much medical attention other than a slow warming up. Chronic cold shock means that the sea turtle has been out in the water for some time and might have gone through a few cycles of warming and cooling. They typically are not in good nutritional health and could have complications emerge from the cold shock process, including bacterial and fungal infections.

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What do you do if you find a cold shocked turtle?

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In North Carolina there are multiple stranding hotlines to call including the official North Carolina Sea Turtle Stranding Hotline (252-241-7367), along with area-specific hotlines that include Ocracoke & Hatteras Island (252-216-6892), Oregon Inlet (252-441-8622), and Wrightsville Beach (833-488-7853).

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(Editor's note: This article was adapted from Can Sea Turtles Get Too Cold During the Winter in North Carolina? which originally appeared at https://news.ncsu.edu/2024/10/sea-turtle-cold-shock/    )