Controlling an invasive species to protect the Gulf of Mexico’s natural habitat
September 27, 2018
By Brock Parker
Much like the South’s favorite non-native and far-reaching plant, kudzu, the Gulf of Mexico has its own invasive species. Lionfish may be beautiful, but they have been creating problems in the Gulf for more than 30 years.
Native to the Indo-Pacific Ocean, lionfish found a new home in the waters around Miami in the mid-1980s. A prized aquarium-dwelling species, there are two theories as to how they found their way into the Gulf. The first theory is owners would release them into the Gulf when they were no longer wanted. The other is when a hurricane came through, there were reports of people who had left aquariums outside, and the fish were then killed or swept away into the waters. No matter how they were freed, a new hunter was on the loose and threatening indigenous fish in the ecosystem.
“The native fish species, because this is an invasive predator, had no idea how to respond. We’ve seen massive decreases in a lot of the smaller fish species, particularly the young,” said Julie Olson, director of the undergraduate program in marine science at The University of Alabama. “It’s something that we may be feeling the effects of for years to come. We haven’t, to my knowledge, seen any species completely wiped out, but they’ve had to adapt to a very different kind of predator. You’re seeing this microevolution in practice as only those that survive are going to be able to have their genetics continue.”
Humans typically don’t have to fear lionfish because they tend to live in deeper areas around reefs or other artificial habitats. Divers around oil rigs and reefs may encounter a community of lionfish, but the chance to see them near the beach is small.
“Most of the time, they will be found in areas where there are a good number of prey items. They’re not normally in the surf. They’re going to found around any type of substrate, whether artificial or natural, where there are communities for them to prey upon,” Olson said.
Because of this, agencies such as the Alabama Department of Conservation and Natural Resources will hold annual challenges for divers in an attempt to cull the lionfish. Catching them involves individually spearing them and using specially-designed holding cases, which decreases the chances of being punctured by their spines.
“They have been responsible for a number of sticks where the spine goes into a human, and the toxins are transferred to the individual. Depending upon the individual and how much of the toxin they get into their body, it can cause massive swelling, problems breathing for some and very intense pain,” said Olson. “I don’t know of any deaths that have occurred, but if you talk to people who have been stuck, many will tell you it’s one of the worst experiences they’ve ever had.”
Divers have more reasons for taking that risk other than helping to protect native fish species. Olson said lionfish taste good, similar to flounder with white flaky meat. Many restaurants and grocery stores around the Southeast now offer the fish to customers, and that’s helping to create a demand and could be a way to help control the population.
However, lionfish aren’t going away any time soon. They can go to depths divers are not easily able to access, and they have antibiotic-producing bacteria on their skin. That protects them from other harmful bacteria, so they’re resistant to foreign pathogens. They can also lay up to 2 million eggs per year, so total eradication of the species in the Gulf isn’t likely. While human hunting and consumption can potentially help maintain the number of lionfish, native fish will need to find new methods of survival against this predator.
“The organisms in their invaded range are starting to figure out how to deal with having them there, so we’re starting to see fewer and smaller lionfish now compared to when this was a huge problem initially,” said Olson. “It’s a matter of the environment learning how to accept them. We’re hearing anecdotally that some of the natural predators are starting to eat the lionfish as well, things like moray eels and nurse sharks. I’m not sure if the nurse sharks will go after a living one, but I’ve seen them happily consume injured or dead lionfish.”