Florida’s beaches suffer regular and random assaults from mats of malodorous sargassum and now there’s a price tag on what the incursions may be costing the state.
A new study from Woods Hole Oceanographic Institute breaks down the estimated annual economic loss to coastal economies in Florida from the worst-hit area of southeast Florida’s forfeiture of nearly $2.7 billion to the Panhandle’s deficit of $143 million.
In total, the blooms of the seafaring weed may be a loss of $3.63 billion annually when fisheries suffer, and visitors cancel hotel reservations, change charter fishing plans, and avoid beachside restaurants, according to the study.
“People spend a lot of money and they expect the beach to look like the pictures and they get down there and it looks like a swamp,” said Fort Walton Beach-based Tonya Wilson, who regularly answers questions about coastal conditions on her Fort Walton Beach Fun and Food Facebook page. “I get bombarded during the summer. People want to know if the water is clear.”
Researchers from Woods Hole in collaboration with the University of Rhode Island published the study in the journal Harmful Algae in October and believe it’s the first of its kind to look at the potential economic damage sargassum does to multiple industries along Florida’s entire coastline.
The study uses economic modeling, satellite observations, tourism and fisheries data, and long term sargassum monitoring to calculate the impact in dollars and cents, and in three categories; expected losses, low end losses and high-end losses.
In expected losses, they range from a low of $4 million in the Big Bend region to $2.68 billion in the southeast, which includes Palm Beach, Broward, Miami-Dade and Monroe counties.
Di Jin, a marine resource economist with Woods Hole and co-author of the study, said having estimates of losses can help justify costs to keep the sargassum at bay or at least mitigate its impacts.
The study also looked at Puerto Rico and the U.S. Virgin Islands.
“Hotel cancellations are for real,” Jin said, specifically referring to reports from the Caribbean and USVI. “But there are repeated reports from communities in Florida in tourism and recreation about complaints over odors and beach inundation.”
What is seaweed and why is it accumulating on Florida’s beaches?
Sargassum, which is a macro algae releases hydrogen sulfide and ammonia when it breaks down, giving off a rotten egg smell.
“Before you even see it, you smell it,” said Florida Atlantic University research professor and algae expert Brian LaPointe. “Then you walk out and see mounds of rotting sargassum leaching brown nasty water that runs right along the beach.”
LaPointe, an expert on algae, said the sargassum beachings began worsening in Florida in about 2014 for reasons scientists are still trying to understand.
Theories include whether a change to the negative phase of the North Atlantic Oscillation shifted strong winds west and south flushing enough sargassum out of the Sargasso Sea to establish a colony in the tropical Atlantic. Researchers identified the “Great Atlantic Sargassum Belt” in 2019 that stretched from off the coast of Africa into the Gulf of Mexico, now referred to as the Gulf of America by the U.S. government.
In the tropics, the sargassum gets more sunshine and a high dose of nutrients that come from upwelling ocean waters, river runoff from South America, and blowing Saharan dust.
But where and when the sargassum will make landfall is fully dependent on several less predictable factors such as winds, coastal currents and tides that can push sargassum mats toward the coast, or away.
In 2023, strong westerly winds drove sargassum all the way to the Azores, which got “buried in it,” LaPointe said.
Still, he was surprised by the pricey economic damage in Florida.
Estimated regional expected annual losses according to the Woods Hole study include:
Northeast Florida, $338 million
Central East Florida, $225 million
Southeast Florida, $2.68 billion
Southwest Florida: $15.8 million
Central West Florida: $223 million
Big Bend or Northwest Florida: $4 million
Panhandle: $143 million
“If we are talking billions, I’m surprised we aren’t doing more in terms of mitigating and protecting beaches,” LaPointe said.
In 2024, 143 million Florida visitors spent $134.9 billion, according to Visit Florida’s most recent full report.
LaPointe said he’s seen some resorts deploy booms to keep the seaweed from reaching the beach, others harvest it while it’s still in the water. Collecting floating sargassum is mostly prohibited in the U.S. because it is protected as an essential fish habitat, according to a 2024 Woods Hole and University of Rhode Island study that looked at the social impacts and management response of sargassum inundations.
Florida’s seaweed beachings could be costly to tourism, fisheries
