Red Tide: Natural bloom not an issue on beach

Reports of a red tide bloom off the coast of Fort Myers Beach and the surrounding area are not as bad as one might understand.

While the organism, scientifically known as Karenia brevis, has been detected in Southwest Florida, it has yet to be called an issue since it has been detected as only lingering offshore with little effects onshore at this time.

According to Florida Fish & Wildlife Conservation Commission recent satellite images from the Optical Oceanography Laboratory at the University of South Florida, weekly status updates have shown past images of bloom patches extending approximately 40 miles alongshore and up to 35 miles offshore, depending on location, between Lee and northern Collier counties. Another report revealed bloom patches extending approximately 60 miles alongshore and up to 15 miles offshore.

“Red tide that is offshore right now is really patchy,” said Town Environmental Sciences Coordinator Keith Laakkonen. “In other words, you can go a mile or two and go from one area with high concentrations to areas with low or no concentrations.”

Laakkonen pointed to a Fish and Wildlife Research Institute HAB (harmful algal blooms) program that reported a patch roughly six miles off of Bonita Beach. That would make that bloom more than eight miles south of the Beach. The prior reports had the patch mainly lingering around the offshore of Sanibel.

USF shows bottom and surface winds blowing south. That directional flow should move that patch even more south, thus not impacting the Beach at all.

“As long as that continues, the bloom movement should follow,” said Laakkonen, “and it should begin to dissipate.”

Laakkonen admits he hasn’t received any reports of respiratory irritation that is traditionally linked with red tide effects on Fort Myers Beach, Lee County or Collier County in the last several days. He does caution that this is historically red tide season in this area.

“Red tide season is spring and fall,” he said.

On Fort Myers Beach, only a few dead fish have washed up along the shoreline in recent weeks.

“They have been scattered and are few and far between,” said Laakkonen. “Frankly, I’m not surprised with all the northernly winds we have had that some have been found on shore. Our public works staff has been picking them up.”

While red tide may appear to be moving closer to shore statistically, Laakkonen reiterated that he believes the bloom may be breaking apart.

“I think the intensity of the bloom is lessening as it is moving closer right now,” he said.

Periodically, small wracks of algae wash up on portions of Fort Myers Beach, leading to speculation of the start of the reddish, harmful algal bloom. But, algae on the beach has nothing to do with red tide.

“Red tide is a microscopic organism that has no relationship to any algae,” said Laakkonen. “Algae washing up can happen any day at any time. There is no human health or environmental threat from that algae.”

Laakkonen has only actually seen a red tide in a visual sense once in his professional career, he says.

“The only time you are going to see red tide if it is an extremely high bloom and very near shore. That is when it will actually discolor the water to a crimson or a red,” he said.

While the threat is low at this time, officials from all environmental organizations are keeping an eye on it.

If anyone has questions about the current status of the beaches, check out area beach conditions reports and interactive maps at or call 1-941-BEACHES (232-2437). Beach goers have that advantage prior to their drive west.

Fort Myers Beach has monitored stations at Wyndham Beach Resort, Newton Park and Lynn Hall Park. Beach Patrol officials reports their findings, including water clarity, dead fish, respiratory irritation and red drift algae, at each site twice a day.

Five-year study unlocks red tide mysteries

Last month, researchers at the Florida Fish and Wildlife Conservation Commission published new findings on Florida’s red tide organism, Karenia brevis, in a special issue of the scientific journal Harmful Algae. This publication is the culmination of an unprecedented collaboration on red tide research in the Gulf of Mexico led by the FWC’s Fish and Wildlife Research Institute and funded by the National Oceanic and Atmospheric Administration.

From this work, researchers unveiled that Karenia brevis uses a variety of nutrients from different sources, including offshore blooms of another algae species, Trichodesmium, as well as decaying fish that die during blooms. Researchers quantified the relative roles of these nutrient sources in affecting blooms.

They also confirmed the importance of physical forces in the occurrence of nearshore blooms of Karenia brevis. In 2010, this red tide organism did not bloom on the southwest Florida shelf because deeper water did not transport source populations to shore; this phenomenon was in stark contrast to 2008, 2009 and, particularly, 2007, when a massive bloom occurred.

Moreover, the work confirmed previous findings that blooms of this particular red tide species, Karenia brevis, are extremely complex and result from a particular suite of physical, chemical and biological factors. This study highlights that effective bloom management integrates short-term solutions of bloom prediction, such as the FWC/USFSP three-day forecasts, with longer-term solutions, including nutrient-reduction strategies.

This project and future projects like it are another step forward in understanding the red tide phenomenon.

“To obtain a comprehensive understanding of red tides in the Gulf of Mexico, we really needed to collaborate with experts across the many fields of marine science, as well as study variations in bloom conditions from year to year,” explained Matt Garrett, a research associate at FWRI. “We were able to put together the big picture of these blooms, which are clearly affected by the physics, chemistry and biology in the ocean.”

Lead investigators at the FWC brought together a diverse group of scientists that included algal biologists, physical oceanographers and chemists from six agencies and universities the University of Maryland Center for Environmental Sciences, University of Miami, Mote Marine Laboratory, Old Dominion University, University of South Florida and the Virginia Institute of Marine Science to understand the physical and chemical drivers of red tides.

The uniqueness of the project came not only from its multidisciplinary nature, but also from its duration and spatial coverage: Between 2007 and 2010, four 14-day research cruises along the southwest Florida shelf, from St. Petersburg to Marco Island and 70 miles offshore, were conducted. The field work was paired with in-depth laboratory studies, which focused on the physiology and ecology of the organism. Most importantly, researchers were able to study bloom and non-bloom years to understand the physical and environmental forces that can cause red tides of the harmful species Karenia brevis.

For more information on red tide, visit and select “Red Tide.” Hard copies of the special issue of the Harmful Algae journal are available upon request by email to [email protected]


Photo: Provided by FWC

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