Save Caribbean snorkeling and 'eat a lion,' conservationists say.

Red lionfish have invaded the Caribbean and threaten to devastate the marine ecosystem in a region renowned for diving and snorkeling.

Here’s the last thing you’d expect to hear from a conservationist: Eat a lion.

But that’s exactly what marine biologists are telling people across the Caribbean, where red lionfish – an invader from the Pacific – threaten to devastate the marine ecosystems that make the region a renowned destination for SCUBA divers and snorkelers.

Lionfish share little with their big cat namesake other than a fan of fins that resembles a flowing mane and, more importantly, a voracious appetite. The fish gobble up the small native fish that are an integral piece of the food chain and an important link in maintaining dazzling underwater seascapes. With no natural predators or diseases to keep the population in check, lionfish are now found on nearly every coral reef from New York to Venezuela and they are multiplying fast. Lacking other options, conservationists are pushing a simple message: capture them and cook them. Fishing communities are learning how to catch and process lionfish, which carry a painful dose of venom in their fins. And restaurants and markets are trying to sell the white flakey filets, which taste like snapper or grouper. 

Researchers say divers and fisherman appear to be the only players that can do anything to keep lionfish numbers down. Native predators, such as large groupers and sharks, don’t recognize lionfish as a prey.

"In addition to further research, it seems that the only thing we can do to control lionfish at this point is to keep spearing them," says Serena Hackerott, a graduate student at the University of North Carolina - Chapel Hill. Ms. Hackerott was the lead author on a 2013 study, published in PLOS One, that found native predators, such as large groupers and sharks, are not controlling lionfish populations to a discernible degree.

"I think that’s our best bet now. I'm not optimistic that natural resistance is going to be enough of an interdiction to control the population."

‘Great eating fish’

Unlike other fish that can be caught on a line, lionfish have to be netted or speared, making it a time-consuming catch. Across the Caribbean, conservation groups have worked with local communities to teach them how to capture and then process lionfish, pointing out how to avoid getting pricked by one of the venomous spines.

“My arm was inflamed all the way up to my shoulder,” says Mildred Minaya, a public relations executive for a Dominican bank who, with six office workers, formed a SCUBA diving group that goes out monthly to monitor and control the lionfish population at a marine park outside of the capital, Santo Domingo. “And I wasn’t even pricked directly. It just nicked me.”

The venomous fins are easily removed, and lionfish are completely safe to eat. Convincing diners of that, however, is another matter.

In Caribbean and Florida restaurants, you can find the fish fried whole, sautéed, served up in traditional sauces, or even raw in sushi plates.

“It’s a great eating fish. Even in places where it’s not being consumed or offered in a restaurant or at a fish retailer, there’s a lot of personal consumption taking place,” says Lad Akins, director of special projects at REEF, a Key Largo-based marine conservation nonprofit. “But it’s an expensive fish to collect, and the market place is still learning how to deal with it.”

At a white tablecloth restaurant off of Santo Domingo’s oceanfront boulevard, José Esteves, a maître d’ has been trying to push the lionfish in coconut milk sauce for the past year.

“It’s not very well known and people are a little hesitant to order it,” Mr. Esteves says. The restaurant, Vesuvio, sells the dish for $16.50, about $4 less than the more popular snapper plate. “There was a campaign, ‘eat a lion,’ that helped a little. The fish has a nice flavor.”

A ‘deepening’ problem

Even if there’s a permanent market for lionfish filets, humans might never be able to get ahead of the problem. New research is showing that lionfish are found at depths divers can’t reach: A submersible vessel spotted one 1,000 feet down off the Bahamas. The recommended maximum for recreational divers is around 100 feet or a little deeper.

No one is certain how lionfish arrived in the Atlantic and Caribbean, but scientists believe enough of the popular aquarium fish were dumped into the Atlantic to create a breeding population. When they arrived, they left behind the diseases and natural predators that have kept the Pacific population in check and the population has exploded in recent years.

Although relatively small (around 12 to 18 inches on average), they are skilled hunters. Just before striking, lionfish blow a jet of water to stun and position their prey headfirst to more easily eat them, researchers believe.

Divers observe them lazily hovering around the coral, eating anything they can fit in their mouths, from crustaceans to small fish. Among those fish they’re eating are the young of fish key to maintaining the health of coral reefs already under stress thanks to warming sea temperatures and ocean acidification.

Take parrotfish, a group made up of some 90 often brilliantly colored reef fish found throughout the Caribbean. Parrotfish feed on the algae that chokes – and eventually kills – coral reefs. They are key in helping reefs rebound from years of die-off, but they’re also a favorite meal for the lionfish. Unfortunately, because lionfish are recent arrivals, young parrotfish don’t recognize them as predators, making them helpless prey.

The seemingly insatiable appetite doesn’t stop there. It also poses a huge risk to Atlantic fisheries as they wolf down the young of fish like snapper and grouper.

Mr. Akins says evolution will eventually find a way to control the lionfish population. What happens in the meantime is the question.

“What a balance will look like is a complete unknown and the fear is that the picture once that balance is formed may be pretty dire,” he says. “The species we rely on commercially could be dramatically impacted to the point of potential collapse.”