Step aside zebra mussels, lionfish are now the worst marine invader that we have ever seen. Not just in the US, but globally. Lionfish may look beautiful but they are veracious predators, which is in part what makes them so devastating. Since the first confirmed population off North Carolina’s coast in 2000, they have spread as far north as New York, as far south as Venezuela, throughout the Caribbean, and the Gulf of Mexico. And now there are obese lionfish. That’s right, obese.
How did this happen? Like many other exotic invaders – giant pythons in the Florida everglades for instance – lionfish entered the waters of the Atlantic when a few aquarium owners decided they no longer wanted them. Through genetic tests, scientists estimate that it took less than a dozen females released from home aquariums to start what is now the worst marine invasion in history. Their numbers have exploded not only because they are incredible predators, but also because they have no natural predators in the areas that they’ve invaded. Even sharks don’t eat them! They grow quickly, start reproducing early, and reproduce year-round, unlike most fish that have just one reproductive season. All of this has allowed them to spread incredibly quickly.
What’s the problem? Invasive species are a huge problem in all natural systems, not just the ocean. And the destruction that lionfish have caused speaks to some of the larger problems that are rampant in the exotic pet trade, including pet owners’ lack of knowledge and understanding of their animals. Lionfish reduce native species by about 70% when they come on the scene. And more than just disrupting natural ecosystems, lionfish may be causing significant reductions in species that humans have worked hard to manage and are interested in consuming, like vermillion snapper and red snapper.
What are we doing about it? Whatever we can think of. Spear fisherman are encouraged to kill and eat them. Fishing derbies and rodeos are held specifically in attempts to reduce their numbers. Cookbooks have been developed to teach people how to safely clean and prepare them. There are scientists at universities in Florida (one of whom is at USF) that are researching ways to control them. The problem is that they spread like wildfire and eat literally everything in their path – they have been observed eating at a rate of 1-2 fish per minute, and their stomachs can expand 30 times their size! Hence the obese fish.