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SCCF partners with Conservancy of SW FL to tag green sea turtles

By Staff | Jun 7, 2017

The SCCF nighttime tagging crew found this turtle false crawling at Casa Ybel May 18. She nested the same night near Tarpon Bay Road. Thirteen days later she nested at Casa Ybel. PROVIDED

This year the Sanibel-Captiva Conservation Foundation has partnered with the Conservancy of Southwest Florida to begin tagging green sea turtles.

“Dave Addison, who is a biologist at the Conservancy of Southwest Florida, leads their sea turtle project there. He got a permit to put satellite tags on greens on Keewaydin. We have more green nesting than they do, so they approached us and said, ‘if we don’t get enough greens on Keewaydin, can we come and put some on your turtles on Sanibel,'” Sanibel-Captiva Conservation Foundation Sea Turtle Coordinator Kelly Sloan said. “I said, ‘of course, sure.'”

She said they then decided they could increase their sample size by four more, which was made possible by donor Mark Banks.

“Now we have a total of eight to put on the two islands. Ideally it will be four and four, but it will depend on where the turtles show up,” Sloan said. “We are in a really good position to have our crew on the beaches at night to learn more about these greens.”

She said the reason greens are so interesting is because they do not know anything about where they go on the southwest coast of Florida after they nest. In addition, learning about their migratory efforts, and their foraging grounds can help protect their habitat.

“Green sea turtles show a very strong biannual nesting pattern in Florida,” Sloan said. “In 2015 it was a really big year on Sanibel, so we are hopeful that 2017 will be another big nesting season.”

Twenty-five nests were found in 2015 on the west end of Sanibel, and two on Captiva.

“Each turtle lays several nests per season, so these could all be different individuals, or the same turtle laying several different clutches on Sanibel, which would be the more likely scenario,” Sloan said.

The green sea turtles typically start making their way to the beaches in June to lay a nest.

“If they false crawl, we of course will focus on that area,” Sloan said. “They have a really strong 10 day internesting interval, so if we miss a green sea turtle nest, we will know to look out for her again in 10 days.”

Once the transmitters are on the greens they can be viewed in real time through a website. The transponders will typically stay on the turtle for a year.

Last year SCCF was very excited to launch the nighttime tagging project for loggerhead sea turtles. The organization received both a permit, and funding from FWC for the program.

“We’ve had this monitoring project going on the beaches for many, many years. Charles LeBuff started the monitoring project in the late 1950s and so we wanted to take it to the next level and actually start learning a little more about the turtles that are nesting on our beaches,” Sloan said.

Last year between May 1 and July 27, the tagging crew encountered 239 turtles representing 157 unique individuals.

“Of the 239 crawls, 50 were on the east end and 189 were on the west end,” Sloan said. “We only ordered enough tags for 100 turtles thinking that was optimistic. So the project was more successful than any of us imagined. Part of that has to do with our record breaking season we had last year with so many turtles on the beach.”

So far this year, the crew has been monitoring the beaches seven days a week and have encountered 48 loggerheads since May 3.

There are a few reasons Sloan thought Sanibel would be a great place to do the tagging program. One of which is to understand the distinct genetic subpopulations of loggerheads in Florida.

“Sanibel is right on the cusp. Everything below Sanibel is thought to be one generic subpopulation and everything above Sanibel is another,” Sloan said. “I was also curious to learn a lot more about habitat selection for nesting sea turtles on our beaches for a variety of reasons.”

Last year, SCCF had a recapture from 1993, a loggerhead that was just 3 miles away from where she was originally tagged. The loggerhead was tagged by Eve Haverfield, who worked with LeBuff for many years before starting Turtle Time in Fort Myers Beach. Haverfield also provided a helping hand to SCCF for many years.

The information reveled that the loggerhead grew only a couple of centimeters in 23 years.

In addition, SCCF has seen a good amount of recaptures from Mote Marine Laboratory & Aquarium, who has a tagging program on Casey Key, and the Conservancy of Southwest Florida, who has a tagging program on Keewaydin Island.

“It kind of gives us a sense of what we call nest site fidelity and where these turtles are going in-between their nesting events. All of this information helps us better protect them,” Sloan said.

When the nighttime tagging crew originally tag a loggerhead, they attach metal flipper tags and a pit tag, the size of a grain of rice that goes under the skin. Sloan said the crew has to encounter the loggerhead again to scan the pit tag for information. Measurements of the loggerhead are taken, GPS coordinates of where they come ashore are recorded, as well as if the turtle nested, or false crawled.

Since the tagging program has been going on for many years throughout Florida, Sloan said they have encountered loggerheads that come from near and far.

“We’ve had this idea that turtles use the same beach to nest every single time. There’s this thought that they come back to the same nesting beach where they were born to lay their eggs. That is true in many cases, but there are also a lot of turtles that use beaches regionally,” she said.

All of the research is furthering conservation efforts for the loggerhead sea turtles now and in the future. Sloan said the crew has already begun educating the public about the importance of using a red filter on flashlights and smartphones.

“They have been handing out red filters to people to put over their flashlights and iPhone lights. We did see a reduction in our disorientation last year,” Sloan said. “It could be for a variety of reasons. The City of Sanibel works really hard to make sure our Dark Skies Ordinance is enforced. A combination with that we are hopeful it is making a difference.”

In addition, the crew spending time on the beach at night has had a positive impact on the amount of coyote depredation with the nests.