Lionfish are native to reefs in the Indian and Pacific oceans and are a popular aquarium fish in the United States. Unfortunately, the release of perhaps as few as a dozen of these pet fish into the Atlantic Ocean during the late 1980s has resulted in a critical lionfish threat to Florida reefs.
Lionfish can decimate the biodiversity of a reef by simply reproducing faster and eating more than the native species. One female lionfish can produce as many as two million eggs in a year. This results in a lionfish density that can be as high as 200 adults per acre. Each of these fish will eat almost anything that it can fit its mouth around, including other fish and crustaceans, and their prey has no innate fear of them. These factors can combine to reduce the population of a reef by 70 to 90 percent.
A crucial aspect of the lionfish threat to Florida reefs is their consumption of species that have a particular role in maintaining the health of the reef. The mudfish, for example, is an algae eater that helps to prevent damage to the reef from algal overgrowth. Without it, coral reefs are in danger of being overgrown with algae, rendering the symbiotic algae living within them to photosynthesize and flourish.
Perhaps the most serious concern about the lionfish threat to Florida reefs is that the lionfish population is proving very difficult to control. The fish have no natural predators and are not susceptible to most of the parasites that are common in the Florida waters. They typically do not bite hooks, and since they live in reefs or wreckage debris they cannot be caught with large nets. The only reliable means of harvesting the fish is to spear them one at a time.
Tournaments and derbies with rewards for harvested lionfish have become popular in some areas, as well as campaigns to encourage restaurants to serve, and patrons to eat the fish. The Florida Fish and Wildlife Conservation Commission now allows divers to use a rebreather when hunting lionfish, with the hope that this will stimulate divers of all types to play a larger part in helping to conserve the reefs.