Florida beaches are littered with dead sea turtles; scientists blame red tide

At least 19 Kemp’s Ridley turtle — the most endangered of the species, are found on the southwestern beaches of Florida.

(National Oceanic and Atmospheric Administration)

Nearly 100 sea turtles, many of which are endangered — are washed ashore on the southwestern beaches of Florida since October. More than half of that number were dead. Marine scientists are now blaming the mass mortality on the current red tide bloom, which is the longest, uninterrupted period of prosperity in more than a decade, officials said this week.

In total, 91 sea turtles have washed ashore on Sanibel and Captiva beaches since October 2017, 58 of which were dead, according to the Sanibel-Captiva Conservation Foundation.

And 50 of the 91 found on the beaches in June and July alone. That is in comparison with the annual average of 30 to 35, Kelly Sloan, sea turtle researcher at the Sanibel-Captiva Conservation Foundation on Sanibel, told the News-Press.

“It’s really sad,” she added.

The death could be a blow to a population of animals that are fighting to make a comeback in the environment, scientists warned, because many of the dead turtles are adults. (Only one in 1,000 sea turtle hatchlings survive long enough to reach the age of 25 years, which is the start of the reproductive period, according to the foundation.


The Kemp’s Ridley turtles — the most endangered of all sea turtles represented with 19 of the 91 turtles found on the beaches, according to the foundation.

“I fear that this event will have an impact for years to come.”

– Heather Barron

Research scientists with the Sanibel-Captiva Conservation Foundation, as Dr. Richard Bartleson, are to blame for the mass mortality on the red tide bloom, a harmful algal bloom (HAB), which occurs when “colonies of algae — simple plants that live in the sea and freshwater — grow out of control while producing toxic or harmful effects on humans, fish, shellfish, marine mammals, birds,” according to the National Ocean Service.

Bartleson is one of the many scientists who worked on the collection of tissue and intestinal samples from the sea turtles that are stranded in the past months. The samples will be tested for brevetoxins, a group of neurotoxins that can affect both humans and animals alike.

In humans, the toxic chemicals from these flowers, that are released into the air as waves on the beach, can have effects on the respiratory tract, causing coughing and sneezing (in fact, a sea turtle expert from Collier County told the newspaper her voice became raspy after she was exposed to the outbreak).

For life in the sea, the toxin “effect on the nervous system and red blood cells,” Bartleson told Fox News on Thursday.

Some marine animals such as fish and sharks — and are affected by toxic substances through their gills. When an animal breathes in, the toxins in the body, eventually reaching the bloodstream. Sea turtles, on the other hand, have no gills, but are also influenced by their mucous membranes or when the ingestion of the red tide bloom, Bartleson said.

A red tide.


The turtles and other marine animals, such as fish, likey do not have the feeling of the toxins when the intake of the flower.


Swimming in circles, lack of coordination, head bobbing and twitching are all symptoms of a sea turtle is exposed to the red tide Karenia brevis organism, which produces the brevetoxins, according to the Florida Fish and Wildlife Conservation Commission.

While the red tide has to occur naturally, Bartleson has already been noted, has worsened, and is extended by human activities such as agriculture, development, and production.

Over the past number of years, the build up of chemical substances such as phosphorus and nitrogen, among other elements that are typically found in the fertilizer — have provided “the perfect nutrients” to worsen the bloom, Bartleson said. These substances reach the sea through surface drains, which are located after a rainstorm, a tropical storm or hurricane.

Bartleson, said the current red tide is partly due to the surface end caused by the Hurricane Irma, while the red tide that affected much of the central west coast in 2005 and 2006 were exacerbated by the active hurricane season in 2004.

In response, Bartleson, together with other scientists, have argued for the use of the wetlands for the redirection of surface drainage, such as swamps act as a natural filter.


As for the turtles, “I fear that this event will have an impact for the coming years,” Heather Barron with the Centre for the Rehabilitation of wild Animals veterinary hospital on Sanibel, told the News-Press.

A graph with the number of sea turtle strandings in the last few months.

(Sanibel-Captiva Conservation Foundation. )

Madeline Farber is a Reporter for Fox News. You can follow her on Twitter @MaddieFarberUDK.

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