It may not be as bad as last year, but as the hundreds of pounds of dead fish on Pinellas beaches have suggested in recent days: Red Tide is back in the Tampa Bay area.
For many in the region, this isn’t your first Red Tide rodeo. And the harmful algal blooms aren’t anything new: They were documented along Florida’s Gulf coast as early as the 1840s.
But with climate change threatening to intensify algal blooms in the future and nearly 1,000 people moving to Florida each day, there are people out there who probably have questions.
And don’t worry — we’ve got the answers. Let’s dive in.
What is Red Tide?
A Red Tide can form when microscopic algae are concentrated at higher-than-average levels.
In this case, the marine organism is called Karenia brevis. You’ll sometimes see it abbreviated to K. brevis.
Karenia brevis is the species responsible for most Red Tides in Florida and the Gulf of Mexico. It produces neurotoxins but can normally be found at low, unharmful levels in the Gulf.
What does it mean when a Red Tide “blooms”?
Red Tide begins to bloom when high levels of Karenia brevis cells are concentrated together.
At high Karenia brevis concentrations, Red Tide can discolor the water and make it look tinted red or brown. Hence the name, Red Tide.
Water samplers will regularly measure the amount of Karenia brevis cells in a liter of water to determine the severity of the problem. The Florida Fish and Wildlife Conservation Commission considers a “bloom” concentration to be 100,000 or more Karenia brevis cells per liter.
At that level, Red Tide can be detected via satellite and respiratory irritation, fish kills and shellfish harvesting closures are all possible.
Where in the Tampa Bay region is Red Tide at its worst?
Like with any harmful algal bloom, current Red Tide conditions can change rapidly. One day your favorite beach might be clear, clean and beautiful. The next, your throat is scratchy and dead fish litter the shore.
That’s because there are plenty of variables that determine when, where and how severe a Red Tide bloom can be. Some of those variables include wind direction, ocean current and water temperature.
This latest round of Red Tide is largely concentrated to the region’s coastal communities, and most of Tampa Bay itself has been spared so far. Still, some of Pinellas County’s most renowned beaches, such as Pass-a-Grille Beach, have seen bloom levels, fish kills and even reports of respiratory irritation over the past week.
The largest amount of dead fish in the Tampa Bay area so far was collected over the weekend at Pass-a-Grille. Cleanup crews cleared more than 1,500 pounds of dead fish from St. Pete Beach over a four-day period recently, according to city officials.
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Oceanographers at the University of South Florida are predicting that the bloom lingers between St. Pete Beach and Madeira Beach over the next few days. The state is regularly testing for Red Tide and they post algal bloom updates twice a week, on Wednesdays and Fridays.
Below: The latest Red Tide water samples from the Florida Fish and Wildlife Conservation Commission.
Could this Red Tide affect my breathing?
Red Tide at high concentrations is known to cause respiratory irritation, and local health departments can issue advisories when conditions worsen.
The Florida Department of Health in Pinellas County issued a warning Friday that some people near affected beaches could have mild symptoms like nose, eye and throat irritation that you’d normally have during a cold. People with asthma, though, could see more severe symptoms, health officials warned.
Breathing impacts happen most often when winds are blowing onshore (moving from the west to the east). If the wind is blowing offshore (moving from the east to the west) then risk of respiratory problems are usually decreased.
The National Centers for Coastal Ocean Science combines current Red Tide conditions and wind forecasts to predict where the worst breathing problems will occur during a Red Tide event. As of Wednesday, Madeira Beach, Treasure Island and the Fort De Soto pier all had a moderate risk for breathing irritation caused by Red Tide.
Below: The latest Red Tide-related respiratory forecast for the National Centers for Coastal Ocean Science
How does this year’s Red Tide compare to last year?
No amount of toxic Red Tide bloom is beneficial for avid beachgoers or people employed at jobs that require them to work long hours near shorelines. But some years are more intense than others.
Unlike last year, this current Red Tide bloom hasn’t impacted much of Tampa Bay itself. In fact, Maximo Park at the southern end of Pinellas County is the only area technically within the mouth of the bay that has experienced high levels of Karenia brevis so far, state data show. Most of the worst conditions are concentrated to Pinellas County beaches, and the St. Pete Beach area remained the most affected as of mid-week.
Last year, scientists say, Red Tide was likely fueled by a human-caused disaster: More than 200 million gallons of polluted water was dumped into the bay between late March and early April off the grounds of the old Piney Point fertilizer plant in Manatee County.
Another metric for tracking the intensity of Red Tide blooms? The amount of dead fish collected from shorelines.
This year’s dead fish collection has so far paled in comparison to the 9 tons of dead fish tossed into dump trucks over a one-day period in St. Petersburg during the 2021 toxic Red Tide bloom.
When it comes to toxic algal blooms, every year brings something new.
Did Hurricane Ian cause this Red Tide?
The expert consensus is pretty clear on this: Hurricanes don’t cause Red Tides, but all the junk they stir up might make them worse.
The communities hit hardest by Hurricane Ian in September had to roil with an intense Red Tide bloom in the weeks after the storm had passed. The Category 4 hurricane made landfall Sept. 28 in Lee and Charlotte counties before ultimately crossing the state.
During and after the storm, millions of gallons of spilled wastewater entered into the Tampa Bay watershed. Plumes of runoff from coastal communities in Southwest Florida showed up on satellite imagery in the days after Hurricane Ian’s landfall. Nutrients like nitrogen, which can be found at high levels in polluted runoff that enters the gulf from land, can fuel harmful algal blooms like Red Tide.
The timing when Red Tides most often flare up also happens to align with the height of the Atlantic hurricane season: Conditions are most ripe for the harmful algal blooms from September to January. Hurricane season usually peaks in early to mid-September and ends Nov. 30.
But the organism that causes Red Tide favors saltier marine environments. So one silver lining to freshwater runoff after a storm when it clashes with a saltier Gulf of Mexico is that Karenia brevis has trouble tolerating low-salinity environments for long periods of time, according to Richard Stumpf, an oceanographer at the National Oceanic and Atmospheric Administration.
How long will Red Tide stick around?
For now, Red Tide is expected to linger offshore of Pinellas County beaches for at least the next few days. Remember that intensity, and therefore potential health risks, can vary from day to day and beach to beach. Your day at Pass-a-Grille could be gorgeous while your friend up at Madeira Beach is coughing up a storm. That’s how these blooms work.
Researchers at the University of South Florida maintain an active Red Tide forecast that documents where they believe the harmful algal bloom will flow in the near-future based on current water samples, wind and ocean currents. The latest forecast shows high levels of Red Tide hugging Pinellas County’s peninsula through at least Saturday. That means anywhere from as far south as Fort De Soto and as far north as Madeira Beach could see impacts in the short term.
Reminder, though: Conditions can change quickly.
Our advice for making the most informed decision: Regularly check in with the Florida Fish and Wildlife Conservation Commission’s water-quality sampling, as well as the university’s forecasts. If you’re a Pinellas County resident who wants close to real-time updates on Red Tide conditions, you can also monitor the county’s own water sampling from their environmental management team. They are testing local areas three days a week during this bloom, and post the updates on https://pinellas.gov/red-tide.
Can I swim in a Red Tide?
During intense blooms, Red Tide can cause skin irritation, rashes and burning and sore eyes.
For this particular bloom, the Florida Department of Health in Pinellas County recommends you avoid swimming around dead fish. You shouldn’t swim in areas with high concentrations, which recently has included southern Pass-a-Grille Beach and the Sister Key area near Shell Key Preserve.
I want to bring my pet to the beach. What should I do?
Here’s the advice from the health experts in Pinellas County: “Keep pets away from water, sea foam and dead sea life.”
It’s probably best to keep your animals away from the beach until conditions improve.
Can I eat local seafood right now?
The Florida Department of Health office in Pinellas County says you shouldn’t harvest or eat molluscan shellfish and “distressed or dead fish” from beaches experiencing a Red Tide.
If you’re an angler and catch a healthy fish in a clear area, the Department still suggests rinsing your fillets with tap or bottled water and tossing out the fish’s guts.
Can humans make Red Tide worse?
Human-caused pollution that enters coastal waters from land can put nutrients into the water that Karenia brevis uses as food, according to the Florida Fish and Wildlife Conservation Commission.
The organism that causes Red Tide exists naturally in an offshore ecosystem, just like fish, phytoplankton and other microorganisms do. But once those blooms drift inshore, “they are capable of using manmade nutrients for their growth,” the state says.
“Red Tides occurred in Florida long before human settlement, and severe Red Tides were observed in the mid-1900s before the state’s coastlines were heavily developed,” the Fish and Wildlife Conservation Commission writes. “No single factor causes blooms of K. brevis. Blooms form as a result of the interactions between biology, chemistry and ocean currents that unite nutrients with light and carry Red Tide to the beach.”
What about climate change? How is that impacting Red Tide?
There’s plenty of data that scientists still need to gather about the link between a warming world and intensifying harmful algal blooms like Red Tide.
It’s difficult to pinpoint how individual algae species like Karenia brevis will respond to a changing climate, scientists say. But experts believe more intense rainfall, induced by climate change that’s exacerbated by fossil fuel emissions, could bring more polluted water into marine ecosystems via runoff. That, in turn, could fuel more Red Tide.
“What would have been a natural phenomenon is subject to exacerbation on failure of effective management,” Douglas Rader, chief oceans scientist at the Environmental Defense Fund, told the Tampa Bay Times last year.
I want to help with the Red Tide situation. What can I do about it?
You can report fish kills or distressed wildlife by contacting the Florida Fish and Wildlife Conservation Commission on the toll-free hotline at 1-800-636-0511. You can also file a fish kill report online.
You can also help reduce the nutrient loads that enter Tampa Bay waters. If you’re a pet owner, one easy fix is to pick up your animal’s waste, because if you don’t, that poop will get washed out through the drains. Nutrients in waste can further fuel Red Tide blooms.
Red Tide resources
There are several online resources that can help residents stay informed and share information about Red Tide:
The Florida Fish and Wildlife Conservation Commission has a website that tracks where Red Tide is detected and how strong it is.
Florida Poison Control Centers have a toll-free 24/7 hotline to report illnesses, including from exposure to Red Tide: 1-800-222-1222
To report fish kills and get them cleaned up in Tampa Bay, call the Florida Fish and Wildlife Conservation Commission at 1-800-636-0511 or file a fish kill report online.
Visit St. Pete/Clearwater, the county’s tourism wing, runs an online beach dashboard at www.beachesupdate.com.
Pinellas County shares information with the Red Tide Respiratory Forecast tool that allows beachgoers to check for warnings.
How to stay safe near the water
- Beachgoers should avoid swimming around dead fish.
- Those with chronic respiratory problems should be particularly careful and “consider staying away” from places with a Red Tide bloom.
- People should not harvest or eat mollusks or distressed and dead fish from the area. Fillets of healthy fish should be rinsed with clean water, and the guts thrown out.
- Pet owners should keep their animals away from the water and from dead fish.
- Residents living near the beach should close their windows and run air conditioners with proper filters.
- Visitors to the beach can wear paper masks, especially if the wind is blowing in.
Source: Florida Department of Health in Pinellas County
Times staff writer Zachary T. Sampson contributed to this report.