Small amounts of Red Tide were just measured in Tampa Bay. Should we be worried?

If you’re planning to spend your weekend on or around the water, should you be worried that small amounts of the organism that causes Red Tide were just detected in Tampa Bay?

We asked that question to the experts who spend their professional lives studying and mapping Red Tide. The biggest takeaway, based on their responses: Keep a close eye on the current water conditions, but don’t let it ruin your plans.

“The present bloom nearshore has been spreading and getting more intense at certain locations, so it would not surprise me if it gets worse before getting better,” said Bob Weisberg, a physical oceanographer at the University of South Florida. But he added this caveat: There are a few unknowns, like how the Red Tide-causing karenia brevis cells will react in the coming days, and just how much could still be lurking offshore.

“If there are still a lot of karenia brevis Red Tide cells offshore, they could be easily adverted into … Tampa (Bay),” said Yonggang Liu, director of the University of South Florida’s Ocean Circulation Lab. “Unfortunately, we don’t know exactly how much and where those cells hide offshore at depth now.”

But here’s what we do know: Water samples posted Wednesday show “very low” amounts of the organism — between 1,000 and 10,000 cells per liter — at both the Skyway Fishing Pier in lower Tampa Bay and Anna Maria Island, according to the latest Florida Fish and Wildlife Conservation Commission data. At that level, it’s possible for people to have trouble breathing and can prompt shellfish harvesting closures at higher concentrations.

Red tide warning were signs posted on local public beaches during a past algal bloom.
Red tide warning were signs posted on local public beaches during a past algal bloom. [ TIFFANY TOMPKINS | Bradenton Herald ]

People living on the southwest Florida Gulf Coast should always be aware of safety conditions on the bay and at barrier island beaches, according to Maya Burke, the Tampa Bay Estuary Program’s assistant director. “Very low” concentrations of red tide isn’t a problem for most paddlers, fishers, hikers or other recreators.

Here’s another way to look at what those measurements mean: Red Tide “was not a serious issue” for the bay on Monday when the samples were taken, Liu said, but there’s a chance it could worsen with time.

The question of whether the public should be concerned is an easier question to answer than whether it will get worse. For instance, some of the worst Red Tide events, like in 2018 and last year, usually peak in the late summer and early fall months. We’re now halfway through November. If Red Tide expands into Tampa Bay over the next few days or weeks, it may not be as bad as those extreme events, Liu said.

Still, the situation to the south is more serious, especially near where Hurricane Ian made landfall in September. Harmful levels of Red Tide (which contain at least 100,000 karenia brevis cells per liter) were documented in 46 samples over the past week. Those include 32 samples in and offshore of Sarasota County, 10 in Lee County, two in Charlotte and one in both Manatee and Collier counties, according to state data.

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Communities still deep in the throes of hurricane recovery are now also grappling with Red Tide’s environmental toll. Scores of fish killed by the ongoing blooms were reported in Manatee, Sarasota, Charlotte and Lee counties, according to Florida Fish and Wildlife Conservation Commission data. On top of that, human health is also at risk with respiratory issues reported in those four counties and Collier County last week.

“All of us should be concerned with red tide outbreaks,” said Peter Clark, the president of Tampa Bay Watch, a conservation nonprofit based at the edge of Shell Key Preserve.

“They are a natural phenomenon, but coastal and watershed development continue to load the bay with nutrients that can prolong and expand a Red Tide bloom,” Clark wrote in an email. “The widespread impacts from last year are still in the hearts and minds of area residents and visitors alike. We do not need another outbreak that dramatically affects our local resources that have not rebounded from last year yet.”

The latest University of South Florida Red Tide forecast shows "very low" concentrations of the algal bloom-causing organism over the next few days. It's something to keep a close eye on, according to the Red Tide experts.
The latest University of South Florida Red Tide forecast shows “very low” concentrations of the algal bloom-causing organism over the next few days. It’s something to keep a close eye on, according to the Red Tide experts. [ Courtesy of the University of South Florida ]

The most recent Red Tide forecast from the University of South Florida shows very low amounts of the algal bloom-causing cells moving through the bay over the next few days. But the worst conditions aren’t expected in Tampa Bay at least in the short-term, according to Lisa Krimsky, a Florida Sea Grant regional specialized extension agent with the University of Florida’s Institute of Food and Agricultural Sciences.

“The conditions in the Gulf of Mexico currently support red tide growth and intensification,” Krimsky wrote in an email. “Whether or not Tampa Bay will get affected will be dependent on future wind conditions (wind direction and strength) and currents, which we don’t have the ability to forecast that far in the future.”

That’s why the public should keep a close eye on current conditions. Or at least pay attention to those who are, like Pinellas County’s environmental management team. The county is currently monitoring for Red Tide from Fort De Soto northward at 11 different sites, according to spokesperson Tony Fabrizio. There have been no instances of Red Tide blooms at any of those locations so far.

“Am I worried? As a resident on the bayside of Pinellas County, not so much — but I am keeping an eye on things and doing my part to reduce my family’s nutrient footprint,” Burke wrote in an email. “If I lived on Anna Maria Island, closer to the higher concentration Red Tide bloom down south, I would probably feel differently. Whenever Red Tide cells are present in nearby waters, the possibility of a bloom intensifying or moving along the beaches (or, less likely, into Tampa Bay proper) is always there.”

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