Florida Fish Busters’ Bulletin
December 2011

Exotic Fishes
By Bob Wattendorf and Vance Crain (Fisheries Biologist)

Jaguar guapote have an attractive black- and-white pattern. Native to Central and South America they showed up in south Florida in 1992.

Florida is not only the Fishing Capital of the World, but it is right up there when it comes to the variety of exotic fishes anglers may pursue. An exotic fish is one that is not native to the area in which it is found. Typically, this is because people moved them from one location to another either intentionally or accidentally, resulting in their illegal release. When they successfully reproduce in these new habitats for several generations, they are termed established. Like native species, some nonnatives may become a nuisance if they create substantial problems.

To many ecologists, any organism that is introduced to a place where it did not historically and naturally occur is a nuisance. However, when you look around Florida you will find many species of plants and animals that are associated with the Sunshine State but were not here 500 years ago when the Spanish first landed. In fact, the Spanish brought many of their familiar edibles from Europe, including oranges, horses and pigs that are now established.

Midas cichlids are often a beautiful orange-red. They were discovered in Florida in 1980, and there native range is Nicaragua and Costa Rica.

It was not until the late 1800s that the first exotic fish were observed in Florida – the not-so-common carp. Evidently, five common carp from Germany were imported to the United States in 1872 for commercial purposes. In 1877, the U.S. Fish Commission imported additional carp from Germany, and for 20 years or so stocked the species as a harvestable food fish throughout most of the United States. Today in Florida, common carp are most abundant in the Panhandle area and support a small but avid fishery of anglers and bow fishermen.

Since common carp became established, another 22 species of fish have become established, meaning they have permanent populations. An additional 11 species are known to have reproduced in Florida’s fresh waters, at least in limited numbers. Add to that seven species that have been collected but are not known to have spawned and you can see that much of Florida is suitable to colonization by foreign fishes. Most of the successful intruders have come from tropical or subtropical climates. Typical sources have been the aquarium trade and individual pet-fish owners, and aquaculture facilities that inadvertently allowed the escape of some of their stock. However, exotic fish have arrived from a variety of sources and for some intriguing reasons (see MyFWC.com for a chart listing the known nonnative fishes occurring in Florida, when they were first observed and where they originated).

Peacock bass are the only non-native fish with a bag and size limit. They were stocked by the state in 1984 and provide a multi-million economic benefit. They are native to the Amazon River basin.

Florida fisheries biologists have studied nonnative fishes and their impacts since the late 1960s and established a Nonnative Fish Research Laboratory in Boca Raton. Although laboratory staff continue to study and be concerned with the presence of nonnative fishes, they have not documented any measureable negative impacts on our native fishes or aquatic habitats. During that time they have been actively involved with exterminating several populations of exotic fishes that were discovered early and in confined areas, including redbelly piranha, pirambeba and threespot ciclid. Natural events, particularly cold spells, have contributed to elimination of 14 species of reproducing nonnative fishes from our waters. Periodic cold snaps cause water temperatures to drop to lethal levels for many nonnative species. Cold weather stresses fish coming from tropical climates more than it does native fish.

On the other hand, staff helped develop the sterile triploid grass carp that is used (under permit) as an aquatic plant-control tool, and the successful introduction of peacock bass, which was stocked as a biological control for unwanted exotic forage species and which, as a secondary benefit, supports a sport fishery in southeast Florida with an economic benefit of nearly $11 million annually.

During the winter cold snap of 2010, peacock bass, along with many other exotic fishes, which anglers have learned to harvest and enjoy, died in large numbers. The exotic fishery on the L-67A Canal is a boom-or-bust fishery that provides an excellent example of how many of these exotic fishes are being utilized, and the effects of the cold snap. The canal is west of U.S. 27 and south of Alligator Alley. It runs 26 miles from Everglades Holiday Park to the Tamiami Trail and is known not only for great largemouth bass fishing, but also for a diverse array of nonnative fish that anglers actively seek. The L-67A Canal provides anglers an opportunity to fish in the heart of the Everglades.

Mayan cichlid, oscar and butterfly peacock bass are the three most popular nonnative species in the canal, but the winter kill in 2010 nearly eliminated them. Catch rates from the prior seven years of creel (2000 to 2009) for Mayan and oscar averaged nine and four fish per hour, respectively. The Mayan cichlid catch rate peaked at 13 fish per hour in 2007. Just before the winter kill, their catch rate was nearly 13 fish per hour. Oscar peaked as well in 2007, with a catch rate of five per hour. Butterfly peacock bass were producing a catch rate of two fish per hour, just before the winter kill. For comparison, a catch rate of one harvestable largemouth bass per four hours (0.25 fish per hour) is considered typical in the southeastern United States. However, in the L-67A Canal, in spite of numerous nonnative fishes, the average catch rate for largemouth bass was more than two bass per hour between 2000 and 2009.

Expenditures by anglers fishing for exotic fishes on the L-67A Canal during the past 17 years was estimated at more than $3 million. During that period, anglers spent 22 percent of their time seeking exotics.

Between 2000 and 2009 there were moderate kills (in 2000 and 2005). However, these exotic species were still able to expand their range outside of the urban canals, partially due to refuges in the water conservation areas that were not as severely impacted, although there are virtually always remnant survivors in the canals as well. The unusually cold winter in 2010 took a toll on most exotics. Nevertheless, once their populations rebound, the amount of time spent fishing (effort) will again rise.

Since 2000, the L-67A fishery overall was comprised of 79 percent resident anglers. However, when you look specifically at exotic species, 71 percent of the anglers were nonresidents. When the exotic bite is on, people travel long distances to fish the L-67A . In the past decade, 58 percent of nonresidents interviewed travelled specifically to fish for exotics. It is impressive to see a local exotics fishery rival that of largemouth bass.

As for surrounding water bodies, urban canals around the more southerly Miami-Homestead area do not get winter kills quite as extreme as L-67A. As a result, the exotic angler effort and expenditure remains more consistent.

With a few consecutively mild winters, these exotic species will rebound in the L-67A Canal. There will be a spike in effort, and the fishing will be red hot! Besides the entertainment associated with fishing for a different and often very colorful fish comes the benefit that, with the exception of peacock bass and triploid grass carp, nonnative fishes do not have bag or size limits. Anglers are encouraged to take as many as they can. It is suggested they be immediately placed on ice. Most are very good eating, and that applies to the Mayan cichlid and oscar, and also to other exotics such as brown hoplos and bullseye snakehead.

Instant licenses are available at MyFWC.com/License or by calling 1-888-FISH-FLORIDA (347-4356). Report violators by calling *FWC or #FWC on your cell, or 1888-404-3922. Visit MyFWC.com/Fishing for more Fish Busters’ columns.

If you would like more information, please contact Bob Wattendorf - Marketing and Special Projects Coordinator, Freshwater Fisheries Management. Phone:  850/488-0520 x 17245, Website:  MyFWC.com/Fishing, E-Mail:  Bob.Wattendorf@MyFWC.com