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Another phenomenal sea turtle nesting season

By Staff | Sep 6, 2017

The nighttime SCCF sea turtle crew used red filters when measuring a loggerhead sea turtle. ALEXIS HORN

The 2017 sea turtle nesting season has been a phenomenal year thus far, due to the number of female loggerhead and green sea turtles using the beaches of Sanibel and Captiva, as well as the hatchlings that have emerged and made it to the ocean.

“It’s really been an amazing nesting season so far. We have lots of nests, great hatch rates, low depredation rates,” SCCF Sea Turtle Coordinator Kelly Sloan said.

Sloan said the last loggerhead to come on shore to lay a nest was Monday, Aug. 28.

“They are still trickling in, but we are basically at the end of the loggerhead nesting season,” she said.

It has been another record-breaking year for sea turtles on Sanibel. Captiva has 189 nests, compared to last year’s record 194 nests.

“Having high nest counts is really encouraging because it means there are more females out there. Seeing these awesome hatchling numbers is really rewarding because the past couple of years our hatch success has been a little bit lower. This year on the western end in particular, our hatch rate is around 75 percent,” she said.

There are more than 25,000 hatchlings on the west end alone with 150 nests still waiting to hatch.

There are 44 nests left on the east end of the island, with a hatch rate of 53.8 percent with 4,032 hatchlings. On Captiva the hatch rate is 48.7 percent with 6,369 hatchlings.

“It’s going to be a phenomenal hatching season despite the two storms. There has been a lot of discussion among the Florida biologist that the high, dry temperatures in south Florida are kind of cooking the hatchlings. It’s just too hot for them to survive,” Sloan said. “It’s possible that all the rain that we got this year has actually helped the hatchlings.”

Although it has been a great year, she said they are still seeing some disorientations taking place for the hatchlings.

“People seem to be pretty compliant as far as exterior fixtures, but there have been some flashlights on the beach and interior lighting. Those are both really easy problems to fix. You can get an approved red filter to go on the flashlight and just shut the blinds at night,” Sloan said. “It’s amazing if you go outside and just look at your house . . . what you can see from a little turtle’s perspective.”

The red filters can be picked up at the SCCF Nature Center.

Another issue has been with beachgoers leaving holes on the beaches, especially Captiva. Crows have also had an impact.

“Just the other day we had a crow pecking at eggs that were exposed due to the storm. There are two different issues going on. Leaving trash on the beach does attract crows, so picking up trash does keep the predators away,” Sloan said.

Another issue has come from individuals sharing they have seen people helping hatchlings to sea at night. Sloan said she believes that people think these little tiny baby sea turtles need help finding their way.

“It actually can be really detrimental to interfere. If you see hatchlings, just stay back,” she said. “We want them to emerge naturally. Unless they are going the wrong way, which in that case they should call our hotline number, 978-728-3663.”

On the plus side, this year, coyotes impacting the nests have decreased. Sloan said she believes maybe 10 have been depredated out of more than 800 nests. The nests were almost exclusively on the west end of the island, with a few on Captiva.

“The goal is to keep the depredation rate below 10 percent. We have definitely achieved that,” Sloan said.

SCCF was able to tag seven out of eight green sea turtles this year for a project they are doing with the Conservancy of Southwest Florida. They were tagged with satellite trackers. One of the satellite trackers stopped transmitting, but the remaining ones are going strong.

“They are kind of all doing different things, which is really interesting,” Sloan said.

One of the green sea turtles, Isabella, was tagged on Sanibel before going north to Sarasota, before swimming down through the Florida Keys. She then made her way up the east coast.

“She is presumably nesting on the east coast,” Sloan said before she made her way to Archie Carr National Wildlife Refuge. “That is the highest density nesting beach in the United States.”

In the past couple of days, Isabella was making her way back down the east coast of Florida.

“She’s very mobile. To my knowledge, well we can’t say for sure what she is doing on the east coast, but I think this is the first case of a turtle nesting on both coasts,” Sloan said.

Green sea turtles come onshore about every 10 days to nest, four to six times a season.

Another green sea turtle, Millie, has not left her spot off the coast of Sanibel. She was the very first one who nested on the beach.

“This is kind of the behavior we would have expected to see,” Sloan said. “This is what loggerheads kind of do. They go nest and then they go off shore and hang out until they are ready to nest again.”

Some of the green sea turtles, Sloan said have traveled off the coast of the Everglades in-between nests.

“It is commonly thought that sea turtles don’t eat while they are nesting. I am not totally sure why else they were going all the way down there if there weren’t good sea grass beds for foraging habitat,” Sloan said. “Whenever you are set out to answer one question, so many others come up. That is what is so much fun about research.”

She said she would not be surprised if they opportunistically forage when they see something easy.

“We are learning so much. People used to think that sea turtles came back to the same exact spot to nest every time as where they were born. But a genetic study that is being done in North Carolina, South Carolina and Georgia is showing that some of them are doing that. Some of them are using all three states during nesting season,” Sloan said. “Although we do know a lot about sea turtles, and there are so many people studying them, there is still so much we don’t know.”

SCCF is now just getting to the part where they can answer the question of where do green sea turtles go after nesting, where home is for them.

There are two green sea turtle nests on the east end and 32 nests on the west end of Sanibel.

To view the results of this year’s nesting season visit www.sccf.org/our-work/sea-turtles. The numbers for Sanibel and Captiva are updated daily.