SANIBEL ISLAND — Splashing his front legs, lifting his head up and down, the reddish brown turtle went round and round the 800-gallon tank.
It's the first time the loggerhead swam in at least 24 hours, when he was rescued with a stretcher from the Captiva Island shore, half unconscious and disoriented after nearly drowning.
The turtle is the latest victim of the unusually persistent Red Tide phenomenon that has been hammering Southwest Florida for eight months now — three months past when it typically recedes.
This algal bloom has been mostly concentrated from Marco Island to Sarasota, causing massive die-offs of sea life and sickening beach-goers.
It shows no signs of abating, and it could spread to the Tampa Bay coastline any day now.
"This is the worst season in the last decade," said Robert Weisberg, a professor and oceanographer at the University of South Florida's College of Marine Science. "And I doubt it's going to go away anytime soon.
"I think it's going to get worse."
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Red Tide comes from the microscopic plant Karenia Brevis that produces a toxin dangerous for animals and humans. The plant reproduces offshore and then ocean currents deliver it to the beaches.
It's an old problem in Florida, dating back to colonial days when Conquistadors first documented it, said Quay Dortch, the ecology and oceanography of harmful algae blooms program manager for the National Ocean Service.
TAMPA BAY TIMES COVERAGE: FLORIDA'S TOXIC ALGAE
Several factors come together to form Red Tide algae blooms. Some are natural processes, such as the decay of other organisms to produce nutrients needed. Other factors are the result of humans, such as contaminating the gulf with fertilizers, sewage and septic tank runoff, which can all exacerbate algal growth.
But this latest outbreak is mysterious, and far more severe.
"I can't really tell you why it's lasted for this long and when it's going to stop," Dortch said. "It's something we don't know right now."
Weisberg said it's the worst Red Tide season he remembers since 2005, and what finally destroyed that bloom was Hurricane Katrina. Weather, such as colder temperatures or even hurricanes, affect ocean currents and can disrupt algae blooms.
But it is hard to predict when, or if, the bloom will affect Tampa Bay.
"I'd need a crystal ball to see what the ocean is going to be like in a month from now," Weisberg said.
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Debbi Peloso, 65, slipped into her black swimsuit and rushed to the beach at 6 a.m. Friday. With shells on her mind and friend Andrea Randell, 57, on her side, she was ready to start her 6-day vacation.
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When the two Tallahassee women arrived at Sanibel Island, however, they started coughing.
Peloso, who's been shelling along the Sanibel shore since 1994, knew right away what it was. For years, Red Tide has caused watery eyes and a painful throat.
"It's nature," she said, shrugging and smiling.
For those with asthma or other respiratory disease, however, Red Tide can be deadly. It's just as bad for sea life, which can inhale or consume the algae through other marine plants or creatures. The suffering of sea turtles has stood out in particular during this outbreak.
From January to July 2018, rescuers have found 287 stranded sea turtles in Collier, Lee, Charlotte and Sarasota counties, said Florida Fish and Wildlife Conservation Commission spokeswoman Michelle Kerr. The average over the past five years for that same period has been 144.
FWC researchers believe 150 to 200 of this year's stranded turtles — up to 70 percent — were victims of Red Tide.
"Other years have been bad, but this year has been particularly bad for sea turtles," said Heather Barron, medical and research director of the Clinic for the Rehabilitation of Wildlife on Sanibel Island. "They're dying in the hundreds. It's depressing."
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Barron believes the massive turtle die-off this summer is because Red Tide usually dissipates by the April-to-October breeding season. But for the past three months, instead of laying eggs, adult turtles have been dying.
What's most disheartening, Barron said, is that most of the dying turtles were either green turtles, Kemp's ridley sea turtles and loggerheads — all endangered species. The body count has also strained the nonprofit clinic's financials. It's budget doesn't account for all the extra blood work, X-rays antibiotics and even surgery required to treat the turtles.
"We're stretching ourselves a bit too thin," Barron said. "This is a catastrophic year."
The Mote Marine Laboratory & Aquarium of Sarasota rescues about 100 turtles every year in Manatee and Sarasota counties. This year, in just seven months, they've already taken in 112, the most in 13 years.
The past two weeks have been particularly difficult, said Gretchen Lovewell, program manager for Mote's stranding investigations program. They've rescued 28 turtles in 10 days.
"It's tough on our staff. It's tough on our hearts," she said. "We just put our head down and keep working, but it's tough."
Contact Jimena Tavel at firstname.lastname@example.org. Follow @taveljimena.