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Where are the turtles? Hatchlings the lowest since 2016

Hundreds of decomposing sea turtles were found off the Mexican coast
Posted at 10:35 AM, Nov 15, 2023
and last updated 2023-11-29 17:49:00-05

SANIBEL, Fla. — You may have heard about the number of turtle nests we saw this past summer, but the problem is a lot of those turtles never made it to the water

“Unfortunately, this year, due to a whole variety of factors we had a real, real low hatch rate,” said Kelly Sloan, SCCF’s Coastal Wildlife Director.

In fact, that hatch rate was the lowest since 2016. On Captiva it was alarmingly low — around 10%. Meanwhile on Sanibel, that number was little better at 32%. But why?

"One piece of the puzzle might be predators,” said Sloan. “We did see a really high predation rate this year compared to past years."

Sloan believes the increase in predators could be linked to less activity on the island post-Ian, and it might force SCCF and FWC to take some actions for next season.

"Predation is considered a natural threat and up to 10% of our nests can be depredated with it being considered ok,” said Sloan. “But since we were about at 44% this year, we are working with FWC, the City of Sanibel, and a couple other of our partners on islands to develop some strategies."

But it wasn't just predators, the turtles also faced the surge waters as Hurricane Idalia passed offshore. SCCF blames the storm for destroying about 100 nests.

"In this case with Idalia, we did see a lot of accretion,” said Sloan. “So, there were about 5-6 feet of sand on a lot of nests…even the nests that were still remaining on the beach, that didn't get wash out by the storm, most of them didn't hatch."

But the likely main culprit is the above normal temperatures we experienced this past summer.

"These developing embryos can only handle a certain amount of heat before they die," saisd Sloan.

Sloan says not only did the heat likely kill developing embryos, but it also likely skewed the hatchling sex ratios. The hotter temperatures will lead to more females. And with the recent heat in Florida the last several years, research from Florida Atlantic University has shown 87% to 100% of hatchling in Florida have been female. A problem which seems to be a growing long-term threat.

"What we do know is that we are not putting that many males into the population,” said Sloan. “So, that could potentially skew sex ratios in adults with not enough males to mate with the females."

Sloan says we wouldn't like see the full impacts of this for 20 to 25 years when current hatchlings reach maturity. Still, she was encouraged by the number of nests last season.

"We are doing really well in a lot of ways, but there are these new and worsening threats that are impacting this already stressed population,” said Sloan. “So, I think now is not to let our guard down.'

Sloan says turtles will start to return in April for the next nesting season.