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Novel Treatment for Coastal Wildlife Ravaged by Red Tide

Analysis by Dr. Karen Shaw Becker

treatment for red tide poisoning

Story at-a-glance -

  • In 2018, Florida’s southwest coast was struck by a mysterious “red tide” that killed massive amounts of wildlife, leaving beaches littered with dead fish, sea turtles, manatees and even a whale shark
  • A record number of about 590 sea turtles died in the latest red tide event, and at least 90 sea turtles were found stranded when red tide enveloped their nesting grounds in 2018
  • An algae species called Karenia brevis releases harmful neurotoxins known as brevetoxins into the water, which bind to fats and are often found in the fatty organs of affected turtles, such as their liver
  • Scientists in Florida have reported that nearly 30 loggerhead, green and Kemp’s ridley sea turtles have been treated and their symptoms subsequently evaporated in just 24 hours
  • A treatment used for mammals and humans alike for decades, veterinarians hope intravenous lipid emulsion therapy will stop the neurological damage in sea turtles caused by red tide toxins

In 2018, Florida's southwest coast was struck by a mysterious phenomenon called red tide that killed massive amounts of wildlife and left beaches littered with dead fish, sea turtles, dolphins, birds and at least one whale shark.

A Miami Herald article1 from the time described the devastation, noting that inlets and canals were clogged with thousands of dead fish, including 10 Goliath grouper, a reef fish that normally lives 40 years and can exceed 8 feet in length and weigh 800 pounds, according to the Florida Museum of Natural History.2

Not only animals in the ocean but seabirds also died en masse, including hundreds of brown pelicans, double-breasted cormorants and other seabirds. In early July 2018, experts examining a whale shark carcass that appeared on a Sanibel Island Beach found red tide in its stomach, intestines, muscles and liver.

At least 90 sea turtles were found stranded when the red tide enveloped their nesting grounds. According to Phys.org, a record number of about 590 sea turtles died in the red tide event that occurred in 2018, described as "(fouling) beaches on both coasts with dead fish and chas[ing] away tourists."3

As if to emphasize the seriousness of the phenomenon, a dead manatee washed up at a nearby boat ramp as hundreds of residents attended a meeting at a Cape Coral yacht club organized by the Army Corps of Engineers to inform residents how the federal government planned to confront the problem.

Novel Remedy for Coastal Wildlife Ravaged by Red Tide

Heather Barron, a veterinarian and research director at CROW Clinic,4 a wildlife rescue center in Sanibel, began treating poisoned birds in October 2018. Barron said she'd begun issuing daily status reports for residents after calculating an average of six dead fish for every foot of local coastline. Speaking on the disaster happening in an area with a reputation as a shell-seeker's paradise, she emphasized to the Miami Herald:

"This is horrific what we're enduring now, but it needs to be a wake-up call to people that clean water is important to more than just wildlife … As the person dealing with all these hundreds of dying animals, I'm upset."5

However, there's hope, at least for red tide-poisoned sea turtles, thanks to a detox remedy originally designed for humans suffering from a drug overdose. In fact, scientists in Florida reported that nearly 30 loggerhead, green and Kemp's ridley sea turtles were treated and their symptoms subsequently evaporated in just 24 hours. Phys.org notes:

"Red tide is caused by an algae species called Karenia brevis that releases harmful neurotoxins, known as brevetoxins, into the water. Brevetoxins bind to fats and are often found in fatty organs, such as the liver, in affected turtles.

The toxins can cause neurological symptoms as spasms, muscle tremors and disorientation, which can lead to mass strandings and death. In high dosages, brevetoxins can lead to seizures in sea turtles. By injecting a fatty emulsion directly into the animals' blood stream, scientists are giving toxins something else to bind to other than the turtles' organs."6

Experts have found that using diuretics on exposed sea turtles results not only in a slow remediation process, but full recovery for those injured by red tide poisoning can take up to three months. This not only reduces their chances for survival but their return to the wild, the optimal remedy following such a disaster.

As red tides wax and wane on the Florida coast, veterinarians are hopeful that the intravenous lipid emulsion therapy will stop the onslaught of sea turtle poisonings that cause neurological damage. A treatment used for mammals and humans alike for decades, it's a first-ever remedy being tested for sea turtles.

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More on How Red Tide Forms

Red tide is a type of marine algae that begins forming off the southwest coast of Florida every year in the late summer and fall months and again in the spring, with exponential growth when it's warmer.

Rick Bartleson, a research scientist with the Sanibel-Captiva Conservation Foundation, says red tides form far from shore, fed by bacteria lining the floor of the Gulf of Mexico, but it's unclear why the algae rise to the ocean surface or drifts eastward, although there's much conjecture and speculation.7 Bartleson said it takes just the right nutrients to form and moderate currents to prevent red tide from being ripped apart.

In the latest case, toxic releases from Lake Okeechobee were the culprit, experts explained, followed by what turned into a massive swath of blue-green algae that began making its way down the Caloosahatchee River.

But it's dependent on the tides, currents and winds. Sometimes it never reaches shore, while other times it envelops and threatens to destroy entire beaches. Further, it may increase exponentially depending on the level of pollution along the coast, says Sanibel Mayor Kevin Ruane, who called his community's occurrence a "perfect storm of coastal pollution and a hot Gulf ignited by flushing nutrient-laden water from Lake Okeechobee."8

Ruane said for the first time since becoming mayor 12 years ago, the city had to hire additional people for the express purpose of cleaning up beach areas to prevent rotting fish from feeding the algae bloom with more nutrients. With the perfect conditions at hand, he added, the area wasn't likely to run out of nutrients very soon.

The fall of 2019 proved to be one of the worst red tide encroachments since the last worst time in 2006, which reportedly lasted more than a year and a half and led to the death of at least 250 manatees.

Data on red tides started being collected in the Gulf in the 1840s, one study shows, impacting human health, as well as marine life with respiratory irritation via aerosolized red tide sea spray and neurotoxic shellfish poisoning, which "presents as a milder gastroenteritis with neurologic symptoms"9 following shellfish ingestion.

Tracking the movement of red tide has become a new and crucial pastime of weather forecasters, fishermen, water recreation vehicle owners, tourists, residents and scores of others, as well as officials at the Florida Department of Environmental Protection. In fact, watching the weather now accompanies greater apprehension and a new urgency.

A Perfect Storm Begins the Red Tide Phenomena

In late August 2017, Hurricane Irma's winds hit South Florida, hammered all 730 square miles of Lake Okeechobee and churned up the mucky bottom. In order to protect the lake's aging dike, in the middle of a $1.7 billion repair job, the Army Corps of Engineers quickly lowered water levels, according to The Miami Herald, which reported:

"In the weeks after the storm, the Corps … released three and four times the amount of water above the threshold considered healthy for the river, according to weekly reports issued by the foundation. The district also back-pumped polluted water into the lake from the L-8 canal in Palm Beach County.

By November, the National Oceanic and Atmospheric Administration's satellite algae tracker began detecting blooms along the coast. Barron said seabirds poisoned by red tide began arriving as early as October, long before the fish kills arrived."10

Seabirds started showing signs of sickness and death before fish and other marine life. "If fish-eating birds are sick, then fish are sick," Barron said. Before the red tide season came to a close, sea turtles began coming ashore to nest.

While red tides are happening more often and the number of sea turtle poisonings will worsen, Justin Perrault, director of research at Loggerhead Marinelife Center in Juno Beach, says the fatty emulsion treatment "could help us get them back into their environment faster, which is important for their populations."11