SANIBEL, Fla. — Following the first ever total beach re-nourishment project on Sanibel (between December 2023 and April 2024), many beach goers asked how it effects our sea turtles.
Earlier this year, the city of Sanibel completed the re-nourishment of every single beach on the island after hurricane ian’s surge eroded many of them. During the project, 400,000 tons of sand was trucked in from a quarry in Moore Haven.
A new study is being conducted by Sanibel Captiva Conservation Foundation is looking into how different characteristics of sand effect the emergence of our baby sea turtles.
“Sea turtles and shorebirds alike rely on these sandy beaches to lay and incubate their eggs,” said SCCF’s Coastal Wildlife Director Kelly Sloan
Sloan and her team are looking into how different sand characteristics can affect our sea turtles nests.
“A lot of what happens inside that egg is genetic, but a lot of it is environmental,” said Sloan
Since 2021, 111 nests have been outfitted with temperature, moisture, and water level loggers on Sanibel and Captiva.
“What we found in some of our preliminary research is that the elevation associated with beach re-nourishment projects can warm up the nests,” said Sloan. “And that can cause some impacts.”
If a nest is too hot the embryos can die, but a warmer nest in general will also lead to more females being born. Plus elevation changes can lead to less moisture in the nest as well.
“Our beaches are getting really hot these days,” said Sloan. “We have all experienced that. And some cooling effect from overwash or groundwater might be beneficial in some cases.
But you also don’t want too much water in the nests either, that's where a beach re-nourishment might be helpful. For Sloan it’s about finding the happy medium for our turtles, especially when SCCF has found 20% reduction in hatchlings on Captiva after re-nourishment versus non-nourished stretches on Sanibel between 2014 and 2020.
“The fact that we are seeing more nests on our beaches is really promising,” said Sloan. “And its a tribute to decades of conservation efforts. But we also need to put hatchlings out to sea to maintain that.”
And of those hatchlings only 1 in thousand will make it to adulthood, stressing the importance giving the hatchlings the best chance in life.
