Sea turtle nests break records on US beaches, but global warming threatens survival

INDIAN ROCKS BEACH, Fla. — Just as they have done for millions of years, sea turtles have been crawling from the ocean to American beaches by the thousands in recent months to lay their eggs. This year, a record number of nests were found in Florida and elsewhere, despite growing concerns about threats from climate change.

In Florida, preliminary state statistics show more than 133,840 hawksbill turtle nests, a record set in 2016. The same goes for green turtles, where the estimate of at least 76,500 nests is well above the previous 2017 figure.

High sea turtle nests have also been reported in South Carolina, Alabama, North Carolina and Georgia, although not all records have been set, such as in Florida, where Justin Perrault, vice president of research at the Loggerhead Marinelife Center in Juno Beach, said the number of nests is high. remarkable this year.

“We had more nests than we had ever seen before on our local beaches,” said Perrault, whose organization monitors Palm Beach County and broke a local record with 4,000 nests. “That’s quite a bit of nesting.”

There are seven species of sea turtles: loggerhead, green, leatherback, hawksbill, Kemp’s ridley, olive ridley and flatback. All are considered threatened or endangered. On summer evenings they come ashore, dig holes in the sand and lay dozens of eggs before covering them and returning to the sea. Florida’s beaches are one of the most important loggerhead breeding grounds in the world.

Only about one in a thousand sea turtles reaches adulthood. They face numerous natural threats, including land and ocean predators, nest disturbances, and the inability to reach water after hatching. This year, along a stretch of Florida’s Gulf Coast where 75 nests were counted, most were wiped out by the wave of Hurricane Idalia in August.

“Unfortunately, almost all of the pre-Idalia nests have been lost due to high tides and flooding on our barrier islands,” said Carly Oakley, senior turtle conservation biologist at Clearwater Marine Aquarium.

Female turtles generally lay eggs on a three-year cycle, leading to years of nesting, she said. “The nesting process is very tiring and during this break the females regain the energy to do the process again,” Oakley said.

Climate change has compounded these challenges, shrinking beaches as sea levels rise and creating more powerful tropical storms. Hotter air, water and sand and changes in the ocean currents that turtles use to migrate also lower survival rates, according to Oceana, an international conservation organization.

Sand temperatures play an important role in determining the sex of sea turtles. In general, warmer temperatures produce more female turtles, and according to researchers at Florida State University, sand temperatures are expected to rise dramatically worldwide by 2100.

“So the warmer the nest is, the more likely the nest is to produce females,” Perrault said. “In addition, the young that come from warmer nests are much smaller and often slower.”

A study led by FSU professor Mariana Fuentes, recently published in the journal Global Change Biology, found that sea turtles will need to nest much later or much earlier than they do now to cope with changing environmental conditions.

Even that may not be enough for every species, says Fuentes, who works in FSU’s Department of Earth, Ocean and Atmospheric Science. Turtles have adapted to changed climates over millions of years, but today’s rapid changes could be happening too quickly for them to evolve, she said.

“We found that even if they change the timing of their nests, that won’t be enough to maintain the temperature of current breeding areas,” Fuentes said.

Sea turtle mothers already have to trudge out of the water to find a good place to nest, which can be tricky in areas where people have built sea walls. Some female turtles make several attempts, known as false crawls, before finding a suitable location.

Raccoons, coyotes and other predators raid the nests and the young, once they dig their way out, must crawl to the sea before they are snatched away by birds and other animals. Electric light can disorient them, causing turtles to go the wrong way on the beach instead of following the light of the moon and stars. And when the lucky ones finally go swimming, hungry fish await.

Michelle Pate, a biologist with the South Carolina Department of Natural Resources, said tens of thousands of hatchlings are not making it to the water, even as the number of nests increases in much of the Southeast.

“If we can’t get the young out of the ocean, increasing the number of nests won’t help,” she said.

The increase in turtle nests this year masks an ominous future for the animals, Perrault said.

“Yes, we are seeing record numbers, but our fry production may not be that great,” he said. “And so in the future, 20 to 30 years from now, and these things come back into their nests, we may not see these record numbers that we’re seeing now.”

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AP video journalist Cody Jackson contributed from Juno Beach, Florida.