Some nonnative fish that are released into lakes and rivers thrive in Florida; alter ecosystem

RUSKIN, Fla. — Nonnative fish eat away at the banks of rivers and lakes – one reason University of Florida researchers caution people not to release unwanted fish.

People sometimes put fish from their aquariums into nearby waterways. Each year, nonnative species can cause $120 billion in damages in the United States. Billions more are spent on prevention, detection control, management and habitat restoration, according to the U.S. Fish and Wildlife Service.

Because of the potential peril nonnative fish pose to aquatic habitats, UF/IFAS researchers studied fish behavioral traits that increase their chances of survival in Florida’s fresh waters. Among the scientists’ findings: If the fish are good parents, they’ll likely establish in Florida’s peninsula.

“When these species are released into the environment, they may survive, find mates and reproduce,” said Katie Lawson, a former UF/IFAS researcher who led the study while a doctoral student at the Tropical Aquaculture Lab in Ruskin. “Some of our established fish species have noticeable impacts.”

This photo shows a Hypostomus — a type of catfish. UF/IFAS researchers studied 125 species of nonnative fish that can establish in Florida’s fresh waters. Scientists found that nonnative fish that care for their young are more likely to establish in Florida’s fresh waters, a key factor in managing them. Meanwhile, they urge people not to release unwanted aquarium fish into nearby bodies of water. Photo courtesy of Katie Lawson.

Two groups of fish common in the aquarium trade — cichlids and armored catfish — contain species that care for their young and find Florida’s aquatic environment highly suitable, said Lawson. Armored catfish, also knowns as “Plecos,” cause the greatest damage. They create burrows that can erode river and lake banks.

“That’s why it’s important that people not release their pet fish. Florida’s climate is a good match for many tropical species and quite a few temperate species, so more species can survive in our waters compared to most other places,” she said.

For the study, UF/IFAS scientists examined the physical and behavioral traits of 125 species and 21 traits in peninsular Florida, southeast of the Suwannee River Basin. Lawson and Hill studied fish species in three groups:

  • Nonnative fish that have successfully established in peninsular Florida.
  • Nonnative fish that have failed to establish in the region.
  • Native fish.

Then, they gathered data on traits for all the species — things like body length, whether they care for their young, size of their eggs and what habitats they prefer.

Researchers found fish species that establish like to live in Florida’s stable and calm canals, lakes and rivers.

This information helps natural resource managers as they assess the risks of invasive or nonnative fish establishing in a given region and the associated harm they can cause, said Lawson, now a researcher at Auburn University.

Until now, most risk invasion assessments of nonnative fish have been done in colder climates such as the Great Lakes region, said Jeff Hill, a UF/IFAS professor of fisheries and aquatic sciences, who supervised Lawson’s research. Although scientists conducted the study in Florida’s peninsula, their findings have implications for other areas of the world.

“Our study has a lot of implications for the southeastern United States and warm regions around the world — for examples, southern and Southeast Asia, South Africa, South America, Central America and Mexico,” Hill said. “People who assess the risk of invasive fish establishing in nonnative regions need to know the behavior traits of nonnative fish in other warm climate regions. Those other areas can host many of the same nonnative species that have established here due to a similar climate match.”


The mission of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is to develop knowledge relevant to agricultural, human and natural resources and to make that knowledge available to sustain and enhance the quality of human life. With more than a dozen research facilities, 67 county Extension offices, and award-winning students and faculty in the UF College of Agricultural and Life Sciences, UF/IFAS brings science-based solutions to the state’s agricultural and natural resources industries, and all Florida residents. | @UF_IFAS



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Posted: December 2, 2021

Category: Invasive Species, Water
Tags: Aquarium Fish, Cichlids, Detection, Establishment, Fish, Florida Peninsula, Invasive, Jeff Hill, Katie Lawson, Lakes, Natural Resource Managers, Nonnative, Prevention, Release, Rivers, School Of Forest Fisheries And Geomatics Sciences, Suwannee River, Tropical Aquaculture Laboratory

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