Python sightings in South Florida continue to make headlines, yet another invader is rapidly taking up residence off Florida’s Atlantic and Caribbean coasts. lionfish, an invasive species from the Indo-Pacific, have rapidly multiplied in recent years and are negatively impacting tropical and subtropical fish populations here in the western hemisphere.
Lionfish are voracious predators, armed with extensive venomous spines on its dorsal, ventral and anal fins. Well camouflaged, they are a nocturnal species that inhabits reefs, where they feed primarily upon small fishes and crustaceans. In its native range, natural checks and balances help to maintain lionfish numbers. However, as with other invasive species, once introduced, they can outcompete native species and have few natural enemies. Lionfish are capable of reproducing year-round, are relatively resistant to parasites and outgrow most natives with whom they compete for food and space. A recent study found a tenfold increase in their abundance from 2004 to 2008 in parts of the Atlantic and Caribbean, and some researchers now estimate lionfish are as abundant as some native grouper species.
Although the first reported sighting in the Florida Keys occurred in January 2009, the lionfish’s current range extends from Cape Hatteras, North Carolina, south to Florida on the Atlantic Coast and throughout most of the Caribbean. Sightings have also been reported off Mexico, Columbian and Belize. Despite being intolerant of colder water temperatures, juvenile lionfish have also been found as far north as New York and Rhode Island. Most sightings have occurred between five and 300 feet on natural hard bottom, coral reefs and artificial reef substrates.
The lionfish invasion in the North Western Atlantic and Caribbean represents one of the most rapid marine finfish invasions in history. Their initial introduction is thought to have occurred during Hurricane Andrew in 1992 when at least six lionfish escaped from a broken beachside aquarium near Biscayne Bay. However, continued release of unwanted lionfish by hobbyists is thought to be the most probable cause of their expansion. Lionfish are a popular and beautiful aquarium fish and approximately 8,000 are imported each year in the Tampa Bay area alone.
Lionfish have become a real threat to many native reef fish populations. Researchers found that within a short period after lionfish penetrated a new area, survival of native reef fishes declined by about 80 percent. Field observations and stomach content analysis showed declines were a direct result of lionfish’s aggressive feeding behavior. Lionfish prey included parrotfish, cardinalfish, damselfish and other ecologically important reef species. Other studies have reported lionfish feeding on juvenile grouper, spiny lobster and other economically important species.
Although it is highly unlikely that lionfish will be completely eradicated, efforts are in place to control lionfish abundance. The Reef Environmental Education Network (REEF) has been working with federal, state and local partners, as well as divers and dive operators, public aquaria and foreign fisheries departments to document lionfish sightings and remove the fish when possible. Divers are encouraged to report any lionfish they encounter by visiting http://www.reef.org/programs/exotic/lionfish.
As of 2007, more than 400 lionfish have been reported by volunteer divers. Fishermen are also helping to curb lionfish numbers. They are reported to be excellent table fare and their consumption is being promoted throughout the Caribbean as a subsistence fishery. The venom is only found in the spines, not the flesh, and cooking destroys any residual toxins. However, extreme caution is urged when handling these fish, as their spines can inflict a powerful sting.
Fortunately, to date, there have not been any confirmed lionfish sightings off Southwest Florida. Gulf currents have provided some security in preventing the natural expansion of lionfish to our coast, but the careless release of just a few of these fish could quickly change this. A lionfish was found near the Sunshine Skyway Bridge in Tampa in 2006, but researchers believe this was an isolated release incident, not part of the natural expansion. However, the explosion of lionfish on other nearby coasts should serve as a reminder that lionfish, nor any other non-native plant or animal, should ever be released into the wild. Such releases are illegal in the state of Florida and can be punishable by up to a year in jail and a $1,000 fine. To report any illegal dumping of non-native species call 1-800-FWC-ALERT. To learn more about the lionfish invasion visit http://coastalscience.noaa.gov/education/lionfish.html.
Bryan Fluech is Collier County’s Florida sea grant extension agent with the University of Florida Cooperative Extension Service and can be reached at 417-6310, ext.204.