Why tons of dead fish are hitting Florida beaches

Bathers and tourists hoping to enjoy Florida’s sandy beaches have encountered a bleak scene in recent months: The shores are dotted with dead fish, worms, and a toxic white foam, all triggered by a harmful algal bloom called “red tide”. The bloom, which experts say has been intensified by local pollution, has posed a serious threat to wildlife and the barely recovering tourism industry.

Since May, the west coast of Florida in the Gulf of Mexico has been hit by a strong red tide. Local docks and beaches have become a scene of desolation, particularly after winds from Hurricane Elsa in July washed tons of fish carcasses ashore.

The outbreaks have been particularly severe in Sarasota, Manatee and Pinellas counties, located on Florida’s southern Gulf Coast. More than 1,700 tons of fish and debris have already been collected from Pinellas County beaches. Both residents and tourists have been sharing photos and videos of the grim scenes, garnering millions of views on TikTok.

Red tide is a regular phenomenon in the Gulf of Mexico caused by blooms of algae called Karenia brevis, which release harmful toxins that can kill aquatic species as large as manatees and cause respiratory irritation in humans. Local wildlife, such as birds that eat dead fish, can also be poisoned.

Authorities have warned locals and tourists to stay away from affected beaches, while local fishermen have seen their livelihoods crippled.

Karenia brevis has affected Gulf waters since at least the 19th century, usually in the fall and winter, after Florida’s rainy season. However, the frequency and duration of recorded red tide blooms have increased since 1995, according to data from the Florida Fish and Wildlife Conservation Commission.

A bloom in 2018 prompted Florida Governor Ron DeSantis to declare a state of emergency, but locals say this year is even worse, thanks to man-made pollution and favorable conditions in which algae can thrive. . This year, the red tide has killed more than three times the number of fish in the Tampa Bay area than in 2018.

‘Human sources of pollution supercharge blooms’

Maya Burke is the deputy director of the Tampa Bay Estuary Program, an association that works to restore and protect the waters of Tampa Bay. She says such a severe red tide in Tampa Bay hasn’t been seen in decades.

I have lived in Florida my entire life and it is very common for us to experience a red tide in the Gulf of Mexico; it happens quite frequently. And we’ve had several big red tides in my life. What is different about this event is what happened in Tampa Bay, it is a really localized effect. To be at a level where I’m killing marine life and causing those respiratory irritations in Tampa Bay as early as May and June, I’ve never seen anything like this in my life.

Karenia brevis is just one part of the Gulf of Mexico ecosystem, these blooms have been documented hundreds of years before really intense human development on the coast. But when they interact with human sources of pollution, that’s what can overload blooms and provide all this fuel for a more frequent and intense red tide. That is what happened this year.

In March and April, 237 million gallons of toxic wastewater from a former fertilizer processing plant, with high levels of phosphorus and nitrogen, leaked or was pumped from the Piney Point Reservoir into local waterways and the Bay of Tampa Officials evacuated nearby residents and deployed emergency workers to control and repair the spill.

The Piney Point Sewage Reservoir is located in South Tampa Bay. © Graphic studio FMM

Officials said the water contained no radioactive substances and would not pose a concern to marine ecosystems, but Burke and other local researchers say this influx of nitrogen into the bay would have a direct impact on red tide blooms.

[The Piney Point discharge] it basically doubled the nitrogen flow to that part of the bay. It was the equivalent of an entire year of nitrogen delivered over a 10-day period. Karenia brevis is not picky, she can consume nutrients from a variety of sources. We think that’s really what caused this bloom to intensify and take off in Tampa Bay in a way that I have never done before in my life.

Warmer waters from climate change can also make conditions more welcoming for these dangerous algal blooms, but the main driver is human development, Burke says, particularly wastewater pollution and car emissions. . He is concerned that the sustained and repeated blooms of the red tide will have a significant impact on local ecosystems.

Usually fish stocks can rebound in about three years or so, but we are coming off a really significant red tide event in the Gulf of Mexico around 2018. So things like fisheries were really starting to reopen. , and then it hits us with another event. We are really concerned about the long-term sustainability of our fish population. But the other thing that worries us is seagrass. […], which performs a lot of ecosystem services that are really important to the bay, it is a really important food source for things like turtles and manatees.

The first thing we can do is control nutrient contamination, regardless of the source. By improving water quality, you are reducing the amount of food available to feed these types of blooms in the future.

As of August 7, the bloom began to decline in the Tampa Bay area, but continues to affect beaches in Sarasota and Manatee counties.

Several conservation groups in Florida have filed a lawsuit against Governor Ron DeSantis and regulatory agencies over the toxic sewage spill at Piney Point. Although state and local funds have been allocated for the coastal cleanup and red tide investigation, local associations and environmentalists have denounced DeSantis’ response to the events, imploring him to declare a state of emergency.

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