Out of the thousands of sea turtle hatchlings emerging from the sand and shuffling toward the ocean around Florida, only 40 were leatherbacks from a Sanibel Island clutch laid by their mammoth mama on April 24.
The rare and endangered leatherback can grow to 7 feet and weigh a ton, making it the world's largest species of sea turtle.
This year’s leatherback, which seldom nests in Southwest Florida, was only the fourth recorded by the Sanibel-Captiva Conservation Foundation to do so on either island — and just happened to be the first of any species to lay eggs on Sanibel this year.
“Leatherback nesting on Florida’s Gulf Coast is rare,” said Jack Brzoza, an SCCF sea turtle biologist. “These turtles more commonly nest on the East Coast.”
Four days later, and 75 miles to the north, volunteers with Mote Marine Laboratory’s Sea Turtle Conservation and Research Program in Sarasota found the first sea turtle nest of the 2024 season on Venice Beach.
The nest was laid by a loggerhead, a threatened species protected under federal law, which is also the most common type to nest in Southwest Florida — followed by the endangered green turtle.
Mote’s volunteers are wondering if this year will bring the return of a Kemp’s ridley, Sarasota County infrequent visitor. While rare like the big leatherback, the ridley is a tiny species that has nested in the Longboat Key-to-Englewood stretch of beach a few times.
“We like to be prepared and patrol early to make sure we catch the first signs of nesting on our beaches,” Melissa Macksey, a Mote biologist, said in April. “Now that we have identified the first nest of the season, we implore beachgoers to be conscious of the sea turtles while enjoying Florida’s unparalleled beaches.”
‘Some exciting things’
This year's nesting numbers are still coming in from around the state, but Robbin Trindell sees positive things for 2024 despite the up-and-down turtle nesting season last year.
“There have been some exciting things that we're hearing about in the turtle world,” said Trindell, the lead sea turtle biologist with the Florida Fish & Wildlife Conservation Commission. “We've had some leatherback nests on the West Coast, something that doesn't happen very frequently, and there have been leatherback nests farther up the East Coast of North Florida.”
Fish and wildlife officials were thrilled last summer when nesting totals broke several records, including 133,941 loggerhead nests and 76,543 green turtle nests statewide in September, which surpassed the records from 2016 and 2017, respectively.
In Southwest Florida, however, the memory of the record-breaking start to 2023’s nesting season is just as memorable as the heartbreaking finish.
On Sanibel and Captiva islands alone, there were more than 1,300 nests when Hurricane Idalia’s brush-by sent storm surge washing over the beach for hours. That, coupled with warmer temperatures linked to climate change, led to the lowest hatchling counts in nearly a decade.
Trindell said research from several Florida universities in recent years isn’t as bleak as reality has proved.
For example, it’s well-known that the temperature of the sand plays a major role in determining the gender of an entire nest of turtle hatchlings, with warmer sand skewing a nest female.
“Nests near the relatively cooler water is where you're more likely to produce your males, and if closer to the dune, it's going to be a little bit warmer depending on that particular beach, but it's also going to be more vulnerable to mammalian predators that come out of the upland,” she said. “The whole nesting dynamic has evolved over time to ensure success given the diverse threats that exist since sea turtles are bound to return to land to nest.”
Trindell said some sea turtles nest in several places during the same year, laying up to six clutches, and varying the distance the nests are from the water. And they’ve discovered adult female turtles can design the nest cavity in a way that can alter the physical conditions, including temperature.
“We’re still researching it. We feel that this is not a new challenge for these animals to have hot temperatures in the areas where they nest,” Trindell said. “There's a high probability some of those nests are not going to make it through the entire nesting season, but they'll still get viable hatchlings into the water from some.”
One thing no turtle mom can fix is shoreline damage done by storms and hurricanes. There would be even more dollar-coin-size hatchlings scrambling toward the Gulf of Mexico right now if not for the stormy weather in recent weeks, which has washed some nests away.
Trindell said it’s an exercise in futility to try to “repair” a storm-ruined nest because the embryos are no longer viable and now have another purpose in nature.
“If you see any eggs on the beach after storms it’s best to leave them in place,” she said. “They are an important source of nutrients for birds and other animals so it’s not a complete waste to the system.”
Loggerhead mania
In Lee County, the SCCF said since the leatherback nested there has been “a cascade” of loggerheads coming ashore, and as of July 2 the species laid more than 645 nests from which 243 hatchlings have emerged.
Brzoza said hundreds more sea turtle nests will be laid along Sanibel and Captiva islands during the next six months, and the foundation’s staff and volunteers will be out daily to protect and tally every one.
“The vast majority of these nests will be laid by loggerheads,” Brzoza said. “But it’s possible there still could be a few more leatherbacks nests laid this season.”
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