Pythons aren’t the only non-native species invading Florida’s ecosystems. Invasive lionfish—ornate reef-dwelling fish native to the Endo-Pacific—have been causing ecological headaches of their own for more than three decades. Luckily, the Florida Fish & Wildlife Conservation Commission has mobilized legions of dedicated spearfishermen who remove tens of thousands of the harmful exotics each year. This spring, anglers participating in the Emerald Coast Open Lionfish Tournament, set a record, removing a staggering 19,560 lionfish from the Gulf of Mexico in just two days.
The tournament was held near Destin, Florida on May 19 and 20. “Divers from around the country
competed for prize money totaling over $100,000 in an effort to eradicate this invasive species in the Gulf of Mexico,” reads a press release from the Destin-Fort Walton Beach Boards of County Commissioners. “The largest lionfish was caught by a diver from the team Dibs on Bottom and measured 17.95 inches while the diving team Deep Water Mafia caught the most lionfish at 2,898.”
Because lionfish sport large venomous spines capable of injecting a deadly neurotoxin into both potential predators and prey, the fish have gone unchallenged since they were inadvertently introduced into South Florida waters in the late 1980s. Since then, they’ve proliferated widely, and their invasive range now encompasses the entire Florida coast. They’ve been spotted as far north as North Carolina. And the warm-water fish have established breeding populations throughout the Caribbean and as far south as the coast of western Brazil.
“They’re so thick if you know where to go,” Eric Johnson, a professor of ecosystem-based fisheries management at the University of North Florida tells Field & Stream. “Anywhere there’s structure, any artificial reefs or hard-bottom areas where you get any kind of relief, they just congregate there. There might be 20 fish within 10 feet of one another, and you can just shoot every one of them. They don’t even move. They’re so easy to catch with spears.”
How did lionfish end up in Florida?
According to Johnson, who’s been catching and studying lionfish for decades, their entire invasive population can be traced back to just a handful of fish. “There are a few anecdotal reports that maybe it was an aquarium release that caused their original introduction, which seems likely,” he says. “There’s also some indication that in 1992, when Hurricane Andrew hit the Miami area, there were seven to nine fish that were released into that area. If you look at the modern genetic analysis, it looks like the genes of 11 individuals are still in the population. It started from a very small number of fish and then just sort of exploded.”
With populations continuing to expand and ranges creeping into other parts of North and South America, Johnson and other marine scientists have all but given up on eradicating lionfish from their non-native ranges. But he says that coordinated efforts to knock their numbers down—like the recent Emerald Coast Open—are vitally important to mitigating the species’ negative ecological impacts on reef ecosystems.
“If you throw enough effort at it, you can have an impact on their populations,” he says. “And you do start to see the recovery of native species, even if it’s just on a small scale.”