by INDIAN ROCKS BEACH, Fla. (AP) — Just as they have done for millions of years, sea turtles by the thousands made their laborious journey from the ocean to U.S. beaches to lay their eggs over the past several months. This year, record numbers were reached in Florida and elsewhere despite growing concern about threats from climate change.
In Florida, preliminary state statistics show more than 133,840 loggerhead turtle nests, breaking a series of records in 2016. The same with green turtles, where the estimate is at least 76,500 nests well above the previous mark set in 2017.
High numbers of sea turtle nests have also been reported in South Carolina, Alabama, North Carolina and Georgia, although not all records have been set as in Florida, where Justin Perrault, vice president of research at Loggerhead Marinelife Center in Juno Beach, said the number of nests there. great this year.
“We had more nests than we’ve ever seen on our local beaches,” said Perrault, whose organization monitors Palm Beach County and broke a local record of 4,000 nests. “That’s a lot of nesting.”
There are seven species of sea turtle: shearwater, green, leatherback, hawksbill, Kemp’s ridley, olive ridley and flatback. All are considered endangered or threatened. They come ashore on summer nights, digging holes in the sand and depositing many eggs before covering up and returning to the sea. Florida’s beaches are one of the world’s most important hatcheries for loggerheads.
Only about one in 1,000 sea turtle hatchlings survive to adulthood. They face many natural threats, including predators on land and in the ocean, disturbance of nests and failure to enter the water after hatching. This year along one stretch of Florida’s Gulf Coast where 75 nests were counted, most were destroyed by the surge from Hurricane Idalia in August.
“Unfortunately, almost all pre-Idalia nests were lost due to the high tides and flooding of our barrier islands,” said Carly Oakley, senior turtle conservation biologist at the Clearwater Marine Aquarium.
Female turtles usually lay eggs in a three-year cycle, which leads to up-and-down nest years, she said. “The nesting process is very exhausting and, in this break, females regain the energy to repeat the process,” said Oakley.
Climate change has added to those challenges, reducing beaches as sea levels rise and causing more powerful tropical storms. Warmer air, water and sand and changes in the ocean currents that turtles use to migrate also lower their chances of survival, according to Oceana, an international conservation group.
Sand temperature plays a major role in determining sea turtle sex. In general, warmer temperatures produce more female turtles, and sand temperatures around the world are projected to increase significantly by 2100, according to researchers at Florida State University.
“So the warmer the nest is, the more likely that nest will produce females,” Perrault said. “In addition, hatchlings that emerge 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 need to nest much later or much earlier than they currently do to cope with changing environmental conditions.
Even that may not be enough for all species, said Fuentes, who works in FSU’s Department of Earth, Ocean and Atmospheric Sciences. Turtles have adapted to a changing climate over millions of years, but today’s rapid changes may be too fast for them to evolve, she said.
“We’ve found that even if they change their nesting time, that’s not enough to maintain the temperature of the nesting sites,” Fuentes said.
Sea turtle mothers must already be out of the water to find a good place to nest, which can be difficult in places where people have built seawalls. Some female turtles make several attempts, called false crawls, before finding a suitable location.
Raccoons, coyotes and other predators raid the nests and hatchlings, as soon as they dig their way out, crawl to the sea before being picked up by birds and other animals. Electric lights can disorient them, causing turtles to go the wrong way on the beach instead of following the moonlight and stars. And when the lucky ones finally start swimming, hungry fish are waiting.
Michelle Pate, a biologist with the South Carolina Department of Natural Resources, said thousands of hatchlings don’t make it to the water, even as nest numbers trend higher across much of the Southeast.
“If we can’t get hatchlings to emerge and make it to the ocean, increasing the number of nests doesn’t help,” she said.
The increase in turtle nests this year spells an ominous future for the animals, Perrault said.
“Yes, we are seeing record numbers, but maybe our hatchling production is not that great,” he said. “And so down the road, 20 to 30 years from now, as these things come back to the nest, we may not be seeing the numbers that we’re seeing now.”
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AP video journalist Cody Jackson of Juno Beach, Florida assisted.
