Promising starts to Florida’s sea turtle nesting season last year and this year have been thwarted by tropical cyclones traveling up the Gulf Coast of the state.
Both Idalia and Debby formed between Cuba and Florida, and both strengthened as they moved north in the Gulf of Mexico.
Both reached hurricane status, both made landfall in August, and both did so in the Big Bend.
Hurricanes Idalia and Debby both inundated thousands of sea turtle nests up and down the coastline under several feet of storm surge along the way.
That, in turn, inspires hundreds of volunteers with special permits to do the work necessary to decide if the nests are still viable.
“Our teams are still working on post-storm assessments,” said Carol McCoy, a spokeswoman for the Coastal Wildlife Club, which monitors sea turtle activity from south Sarasota to northern Charlotte counties. “We lost many yellow stakes, but that’s not to say the nests are gone.”
McCoy’s group looks after Nokomis, where sea turtles nest in greater numbers than anywhere else on the Gulf Coast, south to a small section of Knight Island south of Stump Pass.
“We will work over the next week or so to re-measure nests and decide if they are still there,” she said. “Or, if they are partial or complete washouts.”
This year the beaches they volunteer on were thick with the typical turtle nests from loggerheads, greens, and Kemp’s ridleys.
Unlike regular years, and like several other turtle volunteers along the Gulf of Mexico, the Coastal Wildlife Club found its first-ever nest from a leatherback, the Big Momma of all females that can weigh a ton and grow to eight feet long.
McCoy said sea turtle moms plan for hurricanes.
“Each nesting female turtle deposits several nests throughout the duration of the nesting season - essentially hedging her bets to make sure that even if a storm hits at some point during the nesting season, there is a high probability that at least a few of the nests will incubate successfully”
A nesting strategy
Hurricane Debby made landfall Monday morning near Steinhatchee as a Category 1 hurricane with maximum sustained winds of 80 miles per hour.
Rural Taylor County last August also took the brunt of Idalia, which made landfall in Keaton Beach.
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 heart-breaking finish.
On Sanibel and Captiva islands alone, there were more than 1,300 nests last year 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.
An early report based on a network of sea sensors owned by the Sanibel-Captiva Conservation Foundation found that then-Tropical Storm Debby brought higher levels of storm surge to Sanibel and Captiva islands than did Hurricane Idalia.
The SCCF's sensors found as Tropical Storm Debby passed 130 miles west of the islands on August 4 there were sustained winds of over 25 miles per hour with gusts of up to 50 miles per hour.
The group's coastal biologists are still assessing impacts on sea turtle nests, using GPS coordinates to search for nests where stakes have washed away.
“Data from our moisture and temperature loggers indicate that some nests experienced a significant drop in temperature and increased moisture as the tide influenced the clutch,” said Kelly Sloan, the foundation's coastal wildlife director.
Sloan also said while prolonged inundation can drown developing embryos or wash out eggs, brief washovers can sometimes have a beneficial cooling effect on the nest.
The timing of the storm was earlier than Hurricanes Idalia and Ian, which means there were still more than 500 nests incubating on the beaches and thus a high likelihood of more washed-out nests from Debby, Sloan said.
At last count before Debby, Sanibel and Captiva islands, combined, had 832 loggerhead nests, three green turtle nests, and one leatherback nest. So far, 12,856 hatchlings have emerged, including 12,816 loggerheads and 40 leatherbacks.
“It’s important to remember that storm season directly overlaps with sea turtle nesting season and is a natural part of their life cycle,” Sloan said. "Females have a nesting strategy that accommodates for storms — they lay multiple nests per season every 10 to 14 days so that even if one nest washes away, there’s a high likelihood that another one of her nests will produce hatchlings.”
'Time will tell'
The original nesting numbers for this year have not yet been posted by the Florida Fish & Wildlife Conservation Commission. Anecdotally, turtle volunteers say this nesting season was going well.
David Godfrey, director of the Caribbean Conservation Commission, said it’s too early to tell how damaging to sea turtle nests Hurricane Debby’s romp up the state’s Gulf Coast will be.
Godfrey said, in general, it’s not that Hurricanes Idalia and Debby made landfall where they did.
“The Big Bend doesn’t get a lot of nesting so that’s good,” he said. “But the Clearwater area does, but time will tell as turtle experts assess whether it was damaging inundation or not.”
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