Can we eat our way out of the lionfish invasion?

Yes, say chefs and conservationists. But only if traps or robots can bring in more lionfish from depths divers can't reach. 

Rick Moonen, the culinary world's self-described “godfather of sustainability,” loves to serve lionfish at his seafood restaurant in Las Vegas. Not only is dishing up the invasive fish good for the environment, he says, but it also tastes great, with its mild flavor and flaky texture, perfect for sashimi, tempura, or pan-fried. 

The only problem is lionfish, with its ruby stripes, mane-like spines, and a body that can grow up to 17 inches long and weigh 2 pounds, can only be caught with a spear or net, rendering the marketplace for it wildly inconsistent. 

“One time, the filet was fresh and delicious. Another time it was frozen and OK. A third time, it had freezer burn,” he says in a phone interview from Bermuda, where he emceed a lionfish cook-off last week, leading up to the 35th America’s Cup sailing competition. “It’s like anything else. The kinks have to be worked out.”

Mr. Moonen is one of a growing number of professional chefs, home cooks, and large-scale seafood distributors who attest to a demand for lionfish that just can’t be met. It's not that the fish aren't plentiful. Caribbean populations have grown at an alarming rate since they were inadvertently introduced in the 1980s. They have no natural predators in the west Atlantic, and each lay as many as 50,000 eggs every three days.

But spearfishing is time-consuming, and can only be performed at shallow depths and when the weather is good. In a nutshell, lionfish are multiplying faster than we can catch and eat them, with the Atlantic population 17 times more dense than in its native Indo-Pacific. 

There are others efforts to control invasive species through food. Asian carp in the Midwest is being served fried, Japanese knotweed is being mixed into lemonade, and common periwinkles (tiny snails) in New England are being combined to make escargot. But in this growing invasivore movement, lionfish present a unique problem. 

Now, independent teams of conservationists, roboticists, and volunteers are searching for a solution. One idea being tested is a kind of trap that can keep lionfish in and other marine life out. Another is a robot that can spear or zap and then suck up a lionfish. Whichever of these prototypes proves most effective, however, conservationists say it must be inexpensive enough to be deployed on a large scale. 

“There are lots of good minds coming at this from many different angles, but I also think we have to be realistic about what the base requirements are for a commercial tool, one that is hardy and can withstand the rigors of a saltwater environment,” says Lad Akins, director of special projects at REEF, a Florida-based marine-conservation organization. “I think we should focus on those things that really meet that base criteria. I’m sure with the ingenuity incentive and the gastronomic incentive something will come up that will be effective.”

An aquarium pet turned deep-sea colonizer

Legend has it that in 1992 Hurricane Andrew started the lionfish problem when an aquarium tank, washed out during the storm, dumped six lionfish into Biscayne Bay, Fla. But in all likelihood, exotic pet owners discarded enough of the popular aquarium fish in the Atlantic over the years a breeding population developed. In the 30 years since the first lionfish was spotted off the coast of Florida, the species has spread to reefs as far as Brazil and New York, where they dine on more than 50 species of other fish.

The number of eggs lionfish lay, a lack of a population control, and their insatiable appetites have devastated native species in the Caribbean and Atlantic and the ecosystems those species help to keep in balance. When lionfish decimated the juvenile parrotfish population off the Bahamas, for instance, the algae that parrotfish munch on coral grew with abandon. The coral coverage shrank by as much "as 88 percent in areas; sponge coverage by 96 percent," according to PBS. 

Researchers initially hoped larger prey such as grouper and sharks would either eat lionfish or outcompete them for food. But they have since determined that the best and, perhaps, only way to control lionfish is another species with just as voracious an appetite – humans. 

The first hurdle was to convince chefs and consumers that lionfish are safe to eat once their 18 venomous spines are properly removed. Now, restaurants in the Caribbean, along the Atlantic seaboard, and as far away as San Diego, Calif., have offered the lionfish on their menus. Whole Foods sells it at all of its Florida stores and others across the country.

All in all, 51,420 commercial pounds of lionfish were caught in the US by February 2016, according to the National Oceanic and Atmospheric Administration (NOAA). But a major lionfish distributor tells The Christian Science Monitor that he can’t get enough of the fish to meet his customers’ demands.

“I’m bringing in almost 10,000 pounds a month,” says Joe Glass, founder and president of ReefSavers. “But I’m telling restaurants, ‘I can’t take you guys in until I start securing more fish.’ ”

Whole Foods, the high-end grocery chain, has a similar problem, says David Ventura, the seafood coordinator for the Florida region. “Lionfish usually doesn’t last very long,” at the seafood counter, he says.

Unlike other fish, lionfish can’t be caught on lines. Spear fisherman have proven effective in culling lionfish in shallow waters, say researchers. But the fish has been spotted as deep as 1,000 meters, with large breeding populations documented below the deepest depths divers can go.

Now, independent teams are drawing up and testing unmanned solutions, namely robots and deep-water traps.  

Terminator or trap?

Independent teams of roboticists have been developing remotely operated underwater vehicles (ROV) or autonomous ones that can reach these depths to hunt lionfish.

One of the prototypes that has attracted the most attention is being built by RSE (pronounced “rise”), a project started by the founders of the Roomba robot vacuum and the PackBot that cleaned up the Fukushima nuclear accident in Japan. The group’s latest prototype, a three-and-half-foot-long ROV, was recently tested in a marine environment.

The Guardian LF1, controlled by a human above water, can easily approach the docile lionfish, says co-founder Erika Ebbel Angle. The robot then stuns the fish by zapping it with an electrical charge, and then sucks it into a tube. The ROV can collect up to 15 fish before it must resurface. 

RSE is about six to eight months away from deploying a fleet of 10 to 20 robots, and a year and half away from lowering the cost of one to between $500 and $1,000, says Dr. Angle.

But Mr. Akins at REEF worries this price-point will be too high for commercial fisherman, since lionfish sell wholesale for $5 a pound. 

Another answer could be deep-water traps that only bring in lionfish. As Akins puts it, traps, today, are very good at catching all fish, not just lionfish.  

Steve Gittings, chief scientist for NOAA’s National Marine Sanctuaries, is developing several trap designs that take advantage of the lionfish's attraction to manmade structures. Lionfish tend to hang around these structures more than other fish, he says. So Dr. Gittings's designs include such features as a fish-aggregation device (FAD), which uses a netting or a curtain that allows fish to come and go as they please before the trap is pulled. 

Gittings says initial tests in artificial reefs off Pensacola, Fla., proved successful, but the traps must receive regulatory exemptions to be tested by commercial fisherman on a larger scale. He hopes to secure those exemptions in the next few months.

Other traps in the works include modified lobster traps that allow only lionfish in, as well as traps that lure in lionfish using patterns, pheromones, or sounds.

One concern is ensuring that whatever trap is developed does not bring in by-catch.

Overall, however, those closest to the issue – conservationists, fishermen, distributors, and chefs – are all excited for the results. They note the tastiness of the fish, which they say is a win-win, for the environment and for taste buds.

“If your going to make a movie about an invasive species, the lionfish is going to be the star,” says Rob Ruiz, a chef and owner of The Land & Water Company in San Diego. “It’s a very delicious, flaky white fish. It’s the perfect entry level,” for teaching about invasive species.

Editor's note: A previous version misidentified the location of the lionfish cook-off. It was in Bermuda.