Palm Beach Florida Weekly

Seeing GREEN

Sea turtle nesting continues to grow, especially for greens, but high temperatures may mean fewer male hatchlings.



 

THE EIGHT-MONTH SPAN THAT SEES THREATened and endangered turtles traversing Palm Beach County’s sandy shores in search of nesting sites has come to a close.

The season started March 1, ended Oct. 31 and marked a record-breaking year for green turtles not only locally, with 9,862 nests counted from Boca Raton to Tequesta, but also statewide.

“It’s really good news,” said Sarah Hirsch, data manager at Loggerhead Marinelife Center in Juno Beach. “We were somewhat anticipating that.”

Green turtles typically nest in cyclical patterns. One year, the numbers go down, and the following year, they spike.

“It goes back and forth usually pretty consistently,” Ms. Hirsch said.

The previous record for green turtles along the 9½-mile strand monitored by Loggerhead Marinelife Center was set in 2015, with 5,443 nests, compared with 700 in 2016.

A green turtle hatchling heads to the sea at MacArthur Beach State Park. PHOTO BY CHRIS HALFPAP

A green turtle hatchling heads to the sea at MacArthur Beach State Park. PHOTO BY CHRIS HALFPAP

“We had a pretty good year this year,” Ms. Hirsch said.

She described the overall population of green turtles as “exponentially increasing” because of conservation efforts put into place 30 years ago. Those efforts require turtle-excluding devices, or TEDs, on commercial-fishing vessels, among other rules and regulations aimed at rescuing the revered reptiles.

“We’re finally starting to see the results of those conservation efforts,” Ms. Hirsch said. “Hatchlings born 30 years ago are just now returning to the same beaches to lay their clutches of eggs.”

A raccoon takes eggs from a sea turtle nest along the shore near Gumbo Limbo Nature Center in Boca Raton. COURTESY PHOTO

A raccoon takes eggs from a sea turtle nest along the shore near Gumbo Limbo Nature Center in Boca Raton. COURTESY PHOTO

John D. MacArthur Beach State Park in North Palm Beach had a record-breaking year for green turtles, as well. A total of 1,755 nests were dug along the nearly two miles of coastline.

“I’m pretty stoked about it,” park services specialist Chandler Keenan said.

The park additionally recorded 1,437 loggerhead nests and 14 leatherback nests.

“Those are great,” Ms. Keenan said of the numbers.

 

That’s the good news. Turtle-nesting season 2017 brought bad news, too. The unprecedented heat that has stifled South Florida for three consecutive years is negatively affecting the gender ratio.

“What’s happened is that the weather has been so hot that we haven’t seen any males,” said Jeanette Wyneken, a biology professor at Florida Atlantic University who is leading a study on temperature-dependent sex determination of loggerheads.

Warmer temperatures produce female turtles, while moderate temperatures produce males.

“Hot chicks, cool dudes,” Ms. Wyneken quips. “That’s a very scientific way of saying their sex is controlled by the environment.”

A disproportionate female population — and in the case of Gumbo Limbo Nature Center, an all-female population — is cause for concern, she said.

“2015 became the hottest year on record,” Ms. Wyneken said. “Then 2016 became the hottest year on record. 2017 was also extremely hot, not the hottest but in the top three. That’s indicative of an alarm bell that there may soon be a problem with production. Maybe this isn’t a big deal yet, but when you have record heat, record heat, record heat….

“What should be done?” she asked. “The obvious thing is to stop emitting high levels of greenhouse gases — lower the Earth’s fever, so to speak. It’s not just the turtles. There are similar stories for birds. There are similar stories for insects. It’s impacting more than just your air-conditioning bill. It’s impacting the natural world.”

Gumbo Limbo

Nature Center has participated in the study since its first findings in 2002. This summer, the staff of specialists set cages atop a series of nests so that, after a hatchout, a sampling of babies can be collected and researched. When the babies reach the age where their male / female status is pinpointed, they are taken 10 to 20 miles offshore and released.

“That’s where all their brothers and sisters are hanging out,” marine conservationist Kirt Rusenko said. “We try to get them back to the same spot they would have gone to.”

Sixteen nests of each species, with the exception of leatherbacks because of their low turnout, were caged for the study.

“Hatchlings can’t get out, and predators can’t get in,” Mr. Rusenko said.

Still, predators wreaked havoc all season. Of the 1,071 nests found on Gumbo Limbo Nature Center’s five miles of beach, more than half were scavenged by foxes and raccoons.

“The problem is most likely due to people leaving food for feral cats, which leads to a rapid increase in raccoon and fox populations,” Mr. Rusenko said. “More foxes and raccoons results in more predated sea-turtle nests.”

Most years, the predation rate averages between five and seven percent.

“Feeding wild animals is illegal for a good reason,” Mr. Rusenko said.

Post-hatchling washbacks, also an issue, point to a pollution epidemic. Washbacks occur when the babies manage to scramble out to sea only to ingest foreign matter and die.

“Every single one we’ve gotten this year has had plastic in their gut,” Mr. Rusenko said. “There’s a lot of trash out there.”

At John D. MacArthur Beach State Park, Hurricane Irma and the ensuing king tides brought gallons of garbage ashore, causing false crawls – when females intend to nest and instead retreat – and interfering with hatchlings making their way to the waves.

“Our beach has been completely covered in litter,” Ms. Keenan said. “It’s just a never-ending fight.”

The Friends of MacArthur Beach State Park, the preserve’s support organization, will debut the Citizen Science Marine Debris program in 2018 with the goal of evaluating the types of manmade materials that end up on the dune line and educating the public about it.

“Hopefully, it’ll help people realize some of the impacts we can have, and that there are really easy ways of making the situation better,” Ms. Keenan said. “A lot of it is just plain preventable.” ¦

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