Every year, hundreds of sea turtles wash up on the shores of New England’s Cape Cod bay. Many of these frozen turtles will be rehabilitated, yet scientists still don’t understand why an increasing number of turtles are falling victim to this “cold-stunning” phenomenon.

 

Victoria Snyder, pictured at right, and Amanda Anzalone, pictured center, watch as Don Lewis, pictured at left, handles the turtle they found stranded at the beach. Photo by Poncie Rutsch. Click the photo or here for the full photoessay.

Turtlecast: Listen to hear volunteers find a cold-stunned Kemp’s Ridley sea turtle. By Poncie Rutsch.

On the frigid shores of Cape Cod, a torpid sea turtle sits motionless on the sand. Covered in mud and hidden under a heap of seaweed, this reptile is dehydrated and hypothermic. A group of young biology students spot the immobilized turtle, and call a turtle-rescue hot line.

The students stand guard until the rescue team arrives, and decide to name the turtle “Alfalfa” for the tuft of seaweed sticking up off its head. Alfalfa is one of the lucky ones. The turtle will be rushed off to an intensive care unit in Quincy, Massachusetts, and will likely recover to swim the Atlantic again. This small Kemp’s Ridley sea turtle is one of hundreds to be rescued from the Bay each fall, all victims of the year’s “cold-stunning” event.

Sea turtles are cold-blooded, meaning they depend on a relatively warm climate to maintain their own body temperature. When the water temperature drops below 50 degrees Fahrenheit, extreme hypothermia sets in. Most turtles head south before the water temperature in New England drops, but some get snared by the hooked shape of Cape Cod. The Cape is notorious for sea-animal strandings: dolphins and whales are also often caught by its unusual geography. Turtles who swim too close to shore bump into the natural land barrier that juts into the ocean. When they try to swim east – farther out to sea – they are caught by the tip of the hook. Exhausted, dehydrated, and with body temperatures dropping below the perilous 50 degree mark, the creatures go into shock and wash up on the beach.

This phenomenon, called “cold-stunning,” happens every year. Turtles usually start appearing on beaches in late October or early November, and by late December most have already migrated south or have been killed by the cold temperatures. Many of the turtles that wash ashore dead on arrival. After each high tide, volunteers from the Massachusetts Audubon Society patrol Cape Cod in shifts, scanning the beach for any turtles that may have washed up. Volunteers most often come across a species called the Kemp’s Ridley, the most endangered turtle in the world. But they also encounter loggerheads and green sea turtles, which can grow as large as 500 pounds.

A cold-stunned sea turtle, nicknamed Alfalfa by the people who found it, lies covered with seaweed to prevent the cold wind from reaching it. Photo by XiaoZhi Lim. Click the photo or here for the full photoessay.

Typically volunteers rescue about 200 stranded turtles each year, but that number has been growing steadily. The cold-stunning season in 2012 broke all former records. Of the more than 400 frozen turtles that washed ashore, only 244 were alive. Scientists are not sure why numbers are rising, but some suggest that warming global temperatures may be disrupting normal migration patterns. If waters are staying warm late into fall, turtles may be tricked into thinking it’s still summer time in October, lingering in the north for longer than they should.

Climate change isn’t the only human activity harming these creatures. Six of the seven species of sea turtle are endangered, partially due to hunting and pollution. Some turtles become tangled in traps meant for shrimp and other fish; others are killed by plastic bags, which they mistake for jellyfish and eat.

Dennis Murley, pictured at left, explains that this Kemp’s Ridley sea turtle is about two years old, and probably traveled from Rancho Nuevo, Mexico. Volunteer Kayla Phelps, pictured at right, looks on. Photo by Poncie Rutsch. Click the photo or here for the full photoessay.

Cold-stunning would likely kill many more sea turtles if not for the combined efforts of the Massachusetts Audubon Society and the New England Aquarium. More than 30 years ago, Wellfleet Sanctuary Director Bob Prescott collaborated with Dennis Murley, a citizen turtle enthusiast, to start the turtle rescue campaign. When they first began their cold-stun rescue efforts, most biologists assumed that these turtles were simply lost travelers. Now, they know that the Kemp’s, loggerhead and green turtles regularly visit New England waters. The pair of conservationists noticed these creatures getting stuck on Cape Cod and began organizing the volunteer beach walks that still take place today.

When Audubon volunteers encounter a stunned turtle on the beach, they bring it to the New England Aquarium’s rescue facility in Quincy where veterinarians and lab technicians thaw the creatures very, very slowly. In fact, Audubon volunteers must keep their car heaters off during the trip from the beach to Quincy – a quick transition from a cold beach to a warm car might cause irreversible damage to the reptile’s organs.

Interactive: Click Start to learn how cold-stunned sea turtles make their way back into the ocean. For best experience, click the button on the bottom right to watch in fullscreen. Can’t watch the Prezi? Click here. By Kasha Patel and XiaoZhi Lim.

At the rescue facility, the turtle receives the same kind of care as any ICU patient, and will typically undergo CT scans, ultrasounds, X-ray imaging, blood analysis and endoscopy. Veterinarians perform these tests to check for pneumonia, organ damage, frostbite and other ailments. Immersed in small plastic pools, the turtles are warmed at a rate of 5 degrees per day, ensuring a gradual and safe transition back to a typical body temperature in the mid 70’s.

Once the turtle is happily swimming around in the aquarium’s pools, the vets will release it back into the Atlantic to continue the migration. Of the turtles brought in alive, as many as 90 percent will survive. In recent years, the New England Aquarium has earned the nickname “Sea Turtle Hospital.” While researchers puzzle over the mysterious uptick in sea turtle cold stunning, it’s clear that the efforts of volunteers and veterinarians are helping to keep these endangered creatures swimming in the ocean instead of stranded on the Cape.

 

 

STRANDED is a special report by the graduating Boston University Science Journalism class (January 2014). For more of our stories, visit BU News Service Science section here.
Contributions from Cassie Martin, Kasha Patel, Matthew Hardcastle, Poncie Rutsch, Sara Knight, Sony Salzman and XiaoZhi Lim
BU News Service