STUART, Fla. — Two scientists looking at toxic algae's long-term effects on people say ditch the fish caught in waters contaminated with cyanobacteria.
Rain, heat and pollutants have caused the outbreak of toxic algae blooms this summer in South Florida's Lake Okeechobee and other waterways linked to it, more than 1,000 square miles of fish-filled fresh water. But the risk to human health from any aquatic animals that lives in the midst of the moldy-smelling, fluorescent green sludge is simply too great, they said.
"I would not eat any fish caught in this area right now," said Larry Brand, marine biology and ecology professor with the University of Miami's Rosenstiel School of Marine and Atmospheric Science.
Even if you don't get sick now, you may be setting yourself up for deadly neurological diseases such as Alzheimer's and amyotrophic lateral sclerosis, commonly called Lou Gehrig's disease, or other motor-neuron diseases, according to the 2017 documentary Toxic Puzzle, which the clean-water advocacy group Bullsugar.org screened here earlier this week.
► July 18: Man dies of bacterial infection after eating tainted oyster at restaurant
► July 17: Seaweed invading Florida beaches could become worst bloom in history
► June 14: Florida congressman dares Army Corps to swim in St. Lucie River
The link between the algae's toxins and the incurable diseases comes down to an amino acid, beta-Methylamino-L-alanine, which scientists shorten to BMAA, found in animals killed in the blooms.
"BMAA, a neurotoxin, was found in high levels in the brains of dead dolphins which were sampled," said James Metcalf, a senior researcher with Brain Chemistry Labs in Jackson Hole, Wyoming. "These high concentrations of BMAA we see in the brains of these dolphins, they obviously got it from the fisheries. It indicates you got BMAA in your ecosystem."
So freshwater fish such as bluegill, catfish, cichlids, largemouth bass, shellcracker, speckled perch and tilapia or saltwater fish such as black drum, mullet, redfish, sheepshead, snapper, snook, spotted seatrout, tripletail, and others — could have BMAA contamination if they came from South Florida lakes such as Lake Okeechobee and Blue Cypress Lake or the Caloosahatchee River, St. Lucie River and southern Indian River lagoon.
Someone who eats contaminated food may not experience disease symptoms for 10 or more years, Brand said.
The connection was first observed on Guam after World War II.
During the war, the indigenous Chamorro people had to forage for food, hunting two species of flying foxes, a type of fruit bat, to survive. About 10 years after the war, the population had a spike in motor neuron diseases about 150 times greater than what occurs worldwide, which is about 2 in every 100,000 people, Metcalf said.
"When we found the cyanobacteria was the source of the toxin in Guam, it led to the whole idea that it could be a global phenomenon," he said. "We’ve now shown the toxin can cause the plaques and tangles in the brain."
The lower a fish lives in the water column, the more it could be exposed to harmful toxins, according to Brand's research.
"When you look at the data, it seems like more benthic animals (fish, crustaceans and mollusks that spend most of their time near the bottom of the water) tend to have higher levels of BMAA" because the scum with the dangerous bacteria sits on a river or lake bottom, Brand said.
► July 2016: How toxic green slime caused a state of emergency in Florida
► August 2015: What you need to know about toxic algae blooms
And a fish caught outside an area with the blooms still could be contaminated, said Renay Rouse, spokeswoman for the Florida Department of Health in Martin County.
"Of course, fish move," she said. "The fish you catch away from a bloom may have been in a bloom 5 minutes earlier. So we advise people to closely examine the fish they catch. Other than having been hooked, does it appear to be healthy? Does it have any lesions?"
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