NEWS RELEASE

Florida Fish and Wildlife Conservation Commission

April 5, 1999

CONTACT: Paul Shafland (561) 391-6409

PREVENTION IS THE BEST CURE WHEN IT COMES TO FLORIDA'S AQUATIC ALIENS

Fishes native to distant parts of Africa, Asia, and South America are thriving in Florida's freshwater marshes, swamps, lakes and canals which now host 28 reproducing populations of exotic species. The 1990s alone saw six different exotic species establish a biological foothold.

How these aquatic immigrants affect native fish and habitats are questions pursued by Paul Shafland, head of the Florida Fish and Wildlife Conservation Commission's (FWC) Non-Native Fish Lab Research in Boca Raton.

"Preventing future introductions is of paramount importance because of the possible negative biological and environmental consequences--most of which are difficult to predict" Shafland said.

Most exotic fish thriving in Florida's freshwaters were either released by private aquarists or escaped from holding ponds managed by the tropical fish industry. "Exotic fishes are the basis of an important multi-million dollar industry in Florida," he said. "In fact, Florida produces more than 80 percent of the tropical fish grown in the United States."

The worst case scenario can be pretty grim. Introducing exotics is usually a step down a one-way street. Most illegally introduced pet fishes die, but the survivors may reproduce and become difficult, if not impossible to control or eradicate.

"At the same time exotic species can change the profile of the aquatic community by competing with native species for food or altering the natural balance by excessively aggressive behavior or simply over-crowding limited habitat," he said.

Alien fish may also bring to their new habitat exotic parasites or diseases with severe and often unpredictable impacts on native fishes, according to Shafland. Other species such as piranhas and freshwater stingrays can actually pose a physical or public health threat.

Florida's fresh waters are now home to swamp eels, walking catfish, and clown knifefish from Asia, jaguar guapotes and Mayan cichlids from Central America, four species of tilapia from Africa, and 19 additional species from around the world.

Shafland said the most rapidly spreading populations include the sailfin catfish, Mayan cichlid, and the brown hoplo. These fish species were all discovered in Florida during the past 20 years.

The FWC attempts to prevent exotic fish introductions by developing regulations that define possession criteria for exotic species which are enforced by specially trained law enforcement officers, an on-going public education and information program, and eradication of isolated exotic populations when ever possible.

"On four occasions piranhas have been found in Florida ponds, but we were able to eradicate them before they could spread," he said. "The FWC plans to keep the state's waters free of piranha. Although private citizens in some northern states are allowed to possess piranha, that is not the case in Florida. Piranha are prohibited by law in Florida and violators are subject to prosecution."

Shafland and his fisheries team at the Boca Lab are involved daily in assessing the exotic fish populations in the state, and developing management strategies to cope with any negative consequences. In one notable exception, the FWC introduced an exotic predator, the butterfly peacock bass, to the canals of Miami-Dade and Broward counties to control the existence of a huge population of exotic tilapia.

"This program has been a tremendous success," he said. "The butterfly peacock has reduced the number of tilapia while also creating an $8 million per year sportfishery. The South American butterfly peacock is a world class sportfish, and it has had no known negative impact on native fish. It needs to be emphasized that we thoroughly studied the butterfly peacock and the canals for many years before the first fish was ever released."

Shafland is concerned that the media sometimes projects "The Sky Is Falling!" mentality when it comes to exotic fish in Florida. He points to the near hysteria regarding the mid-1960s discovery of walking catfish as a classic case of press over-reaction.

"Media coverage of the recently discovered swamp eel is reminiscent in many ways of the reports about the dangers posed by the walking catfish," he said. "Predications of an environmental catastrophe turned out to be exaggerated at best and sometimes were nothing more than the product of creative imaginations.

"Yes, we must be concerned about the unauthorized releases of exotic fish, and we should make every reasonable effort to prevent this from happening," he said. "But we should have learned from the walking catfish experience to beware of unsubstantiated doomsday predictions."

Further information about Florida's exotic fish may be obtained by writing: The FWC Non-Native Fish Research Lab, 801 Northwest 40th Street, Boca Raton, FL 33431.

Note To Editors: Photos of certain exotic fishes available upon request.