Stay in the know about wildlife, water quality, and ecosystems on Sanibel and Captiva Islands and in Southwest Florida

SCCF Documents Third Hatching of Leatherbacks on Islands

July 10, 2024
Leatherback Nest Inventory June 2024

On June 28, SCCF’s sea turtle team documented the hatching of a rare, endangered leatherback (Dermochelys coriacea) nest on Sanibel’s West End. During the inventory of the nest, SCCF biologists and permitted volunteers documented 113 eggs, including 40 emerged leatherback hatchlings.

SCCF has only recorded leatherback nesting in three previous years — 2009, 2015, and 2020. Leatherback nesting on the Gulf coast of Florida is rare and mostly sporadic — on average representing only a few of more than 1,000 nests laid per year in Florida by leatherbacks.

“Most leatherback nesting occurs on the east coast of Florida, primarily in Martin and Palm Beach Counties,” said Coastal Wildlife Director Kelly Sloan.

Like this season, the 2009 and 2015 seasons each only had one nest, but in 2020, six nests were laid across Sanibel and Captiva. Several others were documented along the central/southwest coast of Florida as well.

Also in 2020, the first leatherback was satellite tagged on the Gulf coast of Florida in partnership with Florida Leatherbacks, Inc. That leatherback was given the name “Juniper,” pictured at the top of this page and below.

Tracking by Florida Leatherbacks, Inc. in 2020 after satellite tagging in partnership with SCCF during night survey research.

By the time Juniper was tagged during night survey work, there were already three leatherback nests on the islands. After her tagging, the team was able to confirm that she nested several more times — on Sanibel, Captiva, and Cayo Costa as well.

In 2020, Captiva’s first leatherback nest was documented and inventoried, with 51 hatchlings successfully emerging out of 89 eggs total. That nest was the only one of the six nests that successfully hatched on the islands. Those six nests had a combined total of 504 eggs, but no emerged hatchlings were documented from the other five nests.

It should be noted, however, that leatherback sea turtles — compared to the other six species — tend to have lower average hatch success, and the variables associated with this are a continued topic of research statewide.

After her last nest on June 17, 2020, Juniper was tracked wandering up and down the Gulf coast, traveling about 2,300 miles. Her tracker stopped sending a signal shortly after that.

Third Time Leatherback Nest Hatched

With an average of 700 loggerhead (Caretta caretta) sea turtles nesting on Sanibel and Captiva each season, from May to October, this year’s leatherback nest also marked only the third time the SCCF team has documented leatherback hatchlings on our beaches.

Leatherback hatchling on Captiva in 2020

In 2009, SCCF documented the hatching of a leatherback nest on Sanibel’s East End. It was the first known leatherback nest in all of Lee or Collier Counties. Ninety hatchlings successfully emerged from a total of 106 eggs.

The leatherback nest laid on the West End of Sanibel in 2015 did not hatch after washing over nine times. The nest inventory found a total of 57 unhatched eggs and six spacer eggs.

According to the Florida Fish & Wildlife Conservation Commission (FWC), leatherback nesting in Florida occurs primarily from March through July. A female typically nests every two to three years, laying multiple nests per season. 

Leatherbacks lay an average of 73 fertilized eggs and about 25 yolkless eggs per clutch, or “spacer” eggs (Stewart et al., 2006).

With the exception of a few nests on the west coast each year, leatherbacks nest primarily on the east coast of Florida. Click here for FWC nesting data by county from 2019 to 2023.


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