Cold-Stunned Sea Turtles Rescued on Cape Cod

A buzzer sounds and the double doors of the New England Aquarium’s Sea Turtle Rescue Center open wide. Trained volunteers step inside carrying banana boxes containing turtles, many near death, that got too cold to survive at sea.

“Cold-stun” season is in full swing in New England.

More than 100 juvenile turtles have come through those doors in the last few days. Rescued from the beaches of Cape Cod, Massachusetts, most are critically endangered Kemp’s ridleys. With expert intervention and rehabilitation, about 80% of these rescues will recover and return to the sea. But the number of cold-stunned strandings has significantly increased in the last decade — likely due to climate change — adding yet another threat to the survival of sea turtle species.

Cape Cod, a hook-shaped peninsula in the northeast U.S. that curls 70 miles into the Atlantic Ocean, is a hot spot for cold-stunned sea turtles. Marine reptiles are ectotherms that rely on their surroundings to stay warm. The shallow summer waters of Cape Cod Bay are perfect for foraging young turtles who, since the 1970s, have been drawn northward in growing numbers into increasingly globally warmed waters.

But by late October, ocean temperatures can abruptly drop below 50° Fahrenheit (10° Celsius). The sea turtles become hypothermic. Too sluggish to swim out of the Cape’s “hook” to warmer southern waters, the turtles are trapped and drift ashore.

At high tides, patrols organized by the Massachusetts Audubon Wellfleet Bay Wildlife Sanctuary search the Cape’s beaches for stranded turtles. In recent years, the seasonal rescue averages have increased to several hundred turtles per season. Last year that number rose to more than 700 cold-stunned live turtles.

The cold-stunned sea turtles start their recovery in tanks with 55° Fahrenheit water. As their condition improves, they are moved to 65° tanks, and then 70+ degree water. Rewarming these marine reptiles too quickly can be harmful. | New England Aquarium
A record of the rise in Cape Cod sea turtle strandings since 1979. | Liu X, Manning J, Prescott R, Page F, Zou H, Faherty M (2019) On simulating cold-stunned sea turtle strandings on Cape Cod, Massachusetts. PLoS ONE 14(12): e0204717

“Early in the season, we typically see the smaller Kemp’s ridley and green turtles. The larger loggerhead turtles will start to wash ashore in December, though we saw our first loggerhead of the season [this year] on Thanksgiving Day,” said Dr. Charles Innis, director of animal health at the Aquarium, in a press release.  “Every case is unique, and each turtle receives specific care based on its condition.”

The new arrivals barely move when the covers come off the banana boxes. A cadre of skilled volunteers check each turtle’s vital signs, look for injuries, and administer fluids and antibiotics. Every turtle gets x-rayed to check for pneumonia and other health risks. Some will need blood tests or more intensive care.

It might be many months before a turtle is ready for release back to the ocean. At the Aquarium’s facility, the aim is to stabilize the turtles as quickly as possible. Once they can swim and dive in 70-plus degree Fahrenheit water, the turtles are cleared for travel and veterinarians work with the National Oceanic and Atmospheric Administration’s (NOAA) Fisheries Service to identify other facilities located across the U.S. for longer term care. Transport volunteers include private pilots with the non-profit Turtles Fly Too, who take the turtles where they need to go.

Since 1979, staff and volunteers with the Massachusetts Audubon Wellfleet Bay Wildlife Sanctuary have searched for cold-stunned turtles on Cape Cod beaches. Rescues are brought to the New England Aquarium’s Sea Turtle Center. | New England Aquarium
Once the sea turtles can swim, dive, and eat their squid and herring rations, they are stable enough for transport to another facility that has space and expertise for the turtles’ longer-term care. | New England Aquarium
Turtles Fly Too is a non-profit organization that coordinates volunteer private pilots, who donate their time and share cargo space with sea turtles that need transport to recovery facilities or release sites across the U.S. | New England Aquarium

“There are so many people and organizations doing all this work to make sure these sea turtles continue to thrive,” said Adam Kennedy, manager of rescue and rehabilitation, who started as a volunteer and is now in his 20th stranding season.

Globally, most cold-stunning events occur on the U.S. Atlantic and Gulf coasts: especially in Massachusetts, North Carolina, Florida and Texas. Last year, more than 10,000 turtles were stranded in Texas alone. Cold-stun events have also been reported in Uruguay, Spain, Canada, Ireland, Denmark, France, and the UAE.

Trained volunteers check for vital signs when rescued sea turtles arrive. It can be hard to hear the heartbeat in severely debilitated animals, so the volunteers use fetal heart monitors designed for people. Sometimes the pulse can only be detected with an ultrasound. | New England Aquarium
Pneumonia is a common health complication for stranded sea turtles. Some of the rescues need oxygen supplementation to start recovering from their cold-stunning ordeal. | New England Aquarium

All seven species of the world’s sea turtles are at ever-increasing risk from both natural and human-made threats. In Cape Cod Bay, part of the Gulf of Maine, studies show the waters are warming faster than other global waters, increasing the likelihood that more turtles will travel northward in future and get caught in a cold-stun event.

“Every single one of these turtles that get back in the wild — that’s the goal — will hopefully [help] get their [population] numbers back up, said Kennedy. “So, someday, we won’t keep qualifying Kemp’s ridleys with [the words] ‘critically endangered.’ They’ll just be Kemp’s ridleys.”

This story was originally published in Mongabay on December 6, 2021. NowThis has published this story with permission.