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A close-up image of a fish with long fins and brown and white vertical stripes

Florida's Marine Invaders


Invasive species: A species of plant or animal that is not native to an area and that has a harmful effect on the environment or on native species.

Don't Release Your Pet

Many non-native animals and some aquatic plants that are becoming a nuisance in Florida were introduced into our environment as pets or aquarium plants that either escaped or were released into natural areas.

  • For information about non-native reptiles and amphibians in Florida, check out Dr Steve Johnson's website
  • Your Pet Doesn't Belong in the Wild: This powerpoint presentation (821 KB as a pdf file) was developed to teach people about some of the invasive animals in Florida that were introduced as deliberate or accidental pet releases. Note that there is an animation in the presentation--showing the spread of lionfish through the Atlantic Ocean--the website for finding that animation is listed in the notes section for that slide.
  • Don't Release Your Pet Poster: This poster was created for a campaign in Florida where pet stores were asked to help educate customers about the alternatives to pet releases.

Green Mussels

The Asian green mussel, Perna viridis, is closely related to the New Zealand green mussel which is imported to the US as a food item.  Asian green mussels are thought to have been introduced to Florida through shipping activities (in the ballast tank of ships).  They were first reported in Tampa Bay in 1999; by 2002 they had spread to NE Florida and SE Georgia.  In June, 2004, hundreds of green mussels were found growing on boulders on both the north and south sides of the St. Augustine Inlet.  By 2007, the mussels had spread as far north as South Carolina and south into the Indian River Lagoon.  A second mussel, the Charrua mussel, Mytella charruana, has been found in Jacksonville, FL and Savannah, GA in large numbers. To read more about green mussels, click here.

Pacific (pink) acorn barnacles

Large pink acorn barnacles, native to the eastern Pacific Ocean have begun to appear along the Atlantic coast of Florida, primarily on boats in the St Augustine area.  These barnacles are a potential fouling and environmental hazard.


A study released in 2004 revealed the presence of 16 different species of Pacific Ocean fish on reefs in the western Atlantic Ocean.  These fish are thought to have been released into the Atlantic by aquarium owners, as all 16 species are common to the saltwater aquarium trade.  The most abundant fish in the group is the lionfish. 

Lionfish have been reported from waters off Florida's coast since at least the 1980's.  They are now established throughout western portions of the North Atlantic Ocean. Since about 2005, lionfish spread rapidly through the Caribbean and into the Gulf of Mexico. Their northern range expansion seems to be limited by temperature--established populations are found as far north as North Carolina and Bermuda. Occasional lionfish are reported from New England, but they are not believed to survive the winter months in that region. Lionfish have been spotted off the Bahamas at a depth of 1000 feet.

Listen to Maia McGuire speaking about lionfish on NPR's Science Friday (Nov 11, 2016) at this link.

Aquarium owners are reminded to NEVER release plants and animals that have been purchased at a pet store into the environment.  These plants and animals are likely not native to the area.  If they survive, they may begin to take over from native plants and animals, sometimes replacing native species.  One example of this is hydrilla, which used to be a popular freshwater aquarium plant. From 2008-2015, the state of Florida spent about $66 million trying to control this plant in freshwater lakes and ponds.

Terrestrial Invasives

  • Invasive plant race game
    Download these three files to have the materials needed to play the invasive plant race game.  This game, developed by Maia McGuire, teaches ways that invasive plants are introduced, and ways that they can be controlled.
  • Too Many To Count activity (2.3MB PDF)
    Download this to have the materials needed to use this activity, which simulates the use of quadrats for sampling a plant population.  The activity can include the introduction of an invasive plant, which takes over the area over time.
  • AlterNatives Brochure (33 MB PDF) Revised in 2013, this document from the Ixia Chapter of the Native Plant Society provides suggestions of other plants that could be used to replace invasive plants in the landscape.

Other Useful Websites

Green mussel, Perna viridis

Asian pink barnacles, Megabalanus sp.


Brazilian pepper, Schinus terebinthifolius