Invaders of the Reef

As Voracious Lionfish Infest Atlantic and Caribbean Reefs, Underwater Hunters from One Little Island Battle to Keep their Numbers Down.


Some believe the invasion began in 1992 after Hurricane Andrew smashed an aquarium facility in southern Florida and fish escaped into the Gulf Stream. Others speculate it occurred when several disgruntled tropical fish hobbyists from Dania Beach, Florida released their aquatic exotics into the ocean in 1985. How the lionfish escaped into the Sunshine State’s warm waters is now a moot point. The fact is that Pterois volitans, the red lionfish native to the Indo-Pacific, is on the loose in the Atlantic and Caribbean, and it’s multiplying like crazy.

photo of an ornate fish, many-colored spines like feathersphoto Flickr user Jayhem

“Lionfish don’t move around very much,” says Pam Schofield, a fish biologist at the US Geological Survey’s Southeast Ecological Science Center in Gainesville, Florida. “However, their eggs come out in a buoyant mass so they can be fertilized. Once they rise to the surface, the eggs float around for a month before the little ones hatch out. They can move pretty far in that time, especially in a strong current.”

The lionfish have moved far indeed. Today the invasive species can be found up and down the Atlantic coast, as far north as Massachusetts and all the way south to Venezuela. Experts predict the fish will continue to move down the eastern coast of South America as far as Brazil.

Why are scientists so concerned about this fish? After all, the red lionfish is exquisitely beautiful. I have observed them lately in the southern Caribbean waters near the island of Bonaire, moving their wing-shaped, red-and-white striped fins like angels in a stunning underwater ballet. But looks can be deceiving. The fish, with its spiky, venomous appendages, has no natural predators in the Caribbean. And it reproduces rapidly. Schofield says lionfish become sexually mature within their first year; a female can produce 2 million eggs annually. The explosion in the lionfish population, combined with their insatiable appetite, could lead to alarming changes in the region’s underwater coral reef ecosystem. Marine biologists worry that if lionfish disrupt the native food web it could lead to a trophic cascade that would destabilize reef ecology.

A 2005 study in the Bahamas by Oregon State University concluded that a single lionfish can reduce native fish populations on a coral reef patch by nearly 80 percent in just five weeks. One lionfish was observed eating 20 small reef fish in a half hour. Researchers speculate that because lionfish have an untraditional visual profile, native fish allow the predator to swim right up to them before being gobbled up.

“They are eating machines,” says Kalli De Meyer, director of the nonprofit Dutch Caribbean Nature Alliance. The alliance facilitated lionfish workshops for park staff from the six Dutch Caribbean islands during the early stages of the invasion. “They look cute, but they eat all day long, very unusual for a top predator,” she says. “They also eat anything up to their own size and use a novel method for attacking. Lionfish spread out their pectoral fins and drive their prey into a corner before they engulf them. We don’t have any other fish that do that in the Caribbean.”

Schofield says: “The real question is, ‘Do lionfish consume enough of these fish to have a significant impact and how will that impact native fish populations in the future?’ Obviously, more studies are needed. But the speed at which they have spread throughout the region has been the most impressive thing so far. They have blanketed the Caribbean in about three years. That’s very fast.”

The swiftness of the invasion grabbed Ramón De León’s attention back in 2009. De León is the manager of Bonaire’s STINAPA National Marine Park, an underwater wonderworld that surrounds most of the Dutch Caribbean island, known for some of the best diving in the region. With a local dive industry that attracts much of the tourist dollar, protecting Bonaire’s reef fish is a top priority. A wait-and-see approach to the invasion was never an option.

photo of a diver in clear water, spear in hand, lionfish skewered therephoto Patrick Holian

“We took an early, proactive stance,” De León says. “The marine park developed an action plan six months before the first lionfish appeared here. It was based partially on a plan that (then manager) Tadzio Bervoets developed for the Sint Eustatiaus National Marine Park in the northeast Caribbean. After spotting the first fish, we immediately activated our control program. We conducted over 40 hands-on workshops to train divers on how to safely and effectively hunt the lionfish. Now, we have 300 experienced volunteers armed with ELFs.”

The ELF is the marine park’s weapon of choice. It is a spring-loaded, serial-numbered, trident spear that pops a shaft about six inches outward when released. Since lionfish normally float rather than flee, approaching them within that short distance is not a problem. “I just bag the fish once it’s speared,” De León says. “Others put the spear end against the sand or dead coral and kill the fish with a knife while it is still on the ELF.”

De León arranged for me to dive with two experienced hunters – local musician Ralph “Moogie” Stewart and Fernando Simal, a national park employee – to see what a hunt is like. Stewart and Simal came to Bonaire in the early 1990s and met while working as dive instructors at the famed Captain Don’s Habitat dive resort. Captain Don, an American who landed on Bonaire in the 1960s, was a pioneer in bringing dive tourism to the island. He also helped establish the national marine park, and instigated a spearfishing ban in Bonaire. But these days even Captain Don sanctions spearfishing as the best way to deal with the new invader.

It is mid-afternoon when Stewart, Simal, and I enter the gin-clear water at Andrea Two, a shore dive site on the west coast of Bonaire. We drop fast to about 80 feet and begin the hunt. It is a world of super-saturated color, abundant with stony and gorgonian corals. Large schools of blue tang, creole wrasse, and yellowtail snapper cruise the water. The divers keep a fast pace, kicking rapidly while constantly scanning the reef for lionfish.

In five minutes Simal finds one at the entrance of a coral crevice. Seeing us approach, the fish backs slowly into the shadows and disappears. Minutes later, Stewart spots a large, nine-inch lionfish and successfully spears it. He bags his catch, being careful not to get nicked by the animal’s venomous spines. We see two more hovering under a coral overhang. Fernando spears one of the pair. The other flees in the mayhem. It is apparent that lionfish are learning that divers are the enemy. Of the dozen we encounter during the hour underwater, only three lionfish are killed.

The dive was simple compared to others conducted by Simal and Stewart. They often add extra tanks and dive to depths of 150 feet or more, far beyond the recreational diving limit of 110 feet. Those depths require multiple and longer safety stops to avoid getting the dreaded “bends,” decompression sickness. During their final safety stop of 20 minutes or more, the diving duo usually cleans their catch. By the time they exit the water, lionfish fillets are ready for the grill.

Back on the beach, I ask the veteran divers if they regret killing such a beautiful creature. “It’s not so nice,” Simal admits, “but knowing what these fish are doing to the reef, that certainly makes it easier. It’s good to dive with a purpose, and they are delicious. I have no problem with it.” Stewart agrees. “It’s the old predator-prey story,” he says. “As long as I eat it, I philosophically have no problem killing lionfish. Plus, you really have to be on top of your game. It’s a dangerous fish because of those venomous spines.”

Both Stewart and Simal have been stung by lionfish multiple times. Perhaps the most terrifying incident was the first time Simal went hunting in 2009. He was alone and diving deep, nearly 165 feet, when he was stung trying to remove a lionfish from his ELF. “My forearm quickly swelled to about twice its size and my wetsuit was getting really tight, causing me circulation problems,” he recalls. “I chose to take my time surfacing to avoid getting decompression sickness, but the pain was incredible.”

It has become the classic irony of invasive species control efforts: Wildlife lovers forced to kill some wildlife to save others.

After he surfaced, Simal drove himself to the hospital, steering and shifting gears with his uninjured arm. The doctor on duty was unsure what to do since he had never dealt with lionfish toxicity. “He looked it up on the Internet and discovered that the toxin was worse than rattlesnake poison,” Simal says casually. “They put me into intensive care where I got morphine, an antitoxin, and was put under observation. I’ve been stung three times since but the reaction has been less each time.”

Faced with the dangers of venom and deep dives, Bonaire’s volunteer divers have developed a strong camaraderie. They often work as teams with specific roles of shooter or bagger. “I often dive with Fernando and Ramón,” Stewart says. “They are real assassins. One day they were shooting above me and I was collecting the fish into a bag below. Suddenly, it just started raining dead lionfish all around me. I couldn’t believe it. It was shoot-bang, shoot-bang. I thought it was snowing. The lionfish numbers are staggering. They are a prolific fish. They can dominate an area just by simple sexual reproduction. I’ve seen 75 at a time.”

Cooking for a Cause

Pass by Cactus Blue Restaurant in downtown Kralendijk, the capital of Bonaire, and you will see a sign out front: “We kill, serve, and cook lionfish.” Chef Hagen Wegerer, an accomplished diver, is proud to be serving up the predatory invader of Caribbean waters. He is one of a growing number of Caribbean restaurateurs who have added this firm, white fish to the menu. “Two years ago, (when) people were out there diving and bringing them to me, they were only four to six inches in length, quite small. I started using those fish for ceviche, fish cakes, and fritters,” Wegerer says.

Lionfish items on the menu intrigue customers, especially tourists seeking an adventurous culinary experience. And these days the fish are larger, allowing Wegerer to serve them as an entrée. “People just love to see the whole lionfish on the table. The spines, skin and venom are removed but the fish is served still on the bone.”

Wegerer says preparing the fish can be tricky. “You can quite clearly see the toxin sacks when you open up the fish,” he explains. “If you cook things properly, nine times out of ten everything should be fine. Having said that, I always remove the toxin sacks. I like to make sure it’s a clean fish by the time it gets to the table.”

Customers are choosing the fish for more than simply taste, Wegerer says. Eco-gastronomy has come into play. “People are also enjoying the fact that they’ve done something for the environment – eating a fish that is consuming native reef residents,” he says.

Unable to visit the Cactus Blue and sample Chef Wegerer’s tasty lionfish ceviche? Why not make some of your own? Just pick up a copy of the 2011 Lionfish Recipe Book, put together by the Turks and Caicos Islands’ Environment and Coastal Resources Department. Or try out the Lionfish Veracruz and pesto-seafood lasagna recipes in Lionfish Cookbook – The Caribbean’s New Delicacy, published by the Reef Environmental Education Foundation.

But not everyone is dining on this newcomer to the reef. Sint Maarten and other northeast Caribbean islands have discovered high levels of ciguatoxin in their lionfish populations. Ciguatoxin is a poisonous organic compound often found on seaweed and algae eaten by small fish. The toxin passes up the food chain to the larger reef predators like barracuda, snapper, and of course, lionfish. Ciguatoxin remains in the fish even after it’s cooked.

“We tested several samples of lionfish and have unfortunately found that an uncomfortably high percentage showed the presence of ciguatoxin in the meat,” says Tadzio Bervoets of Sint Maarten’s Nature Foundation. “Therefore, we do not recommend that lionfish be eaten from our waters. This is very bad news for us as we were planning on promoting lionfish as an edible, commercially viable fish, which we hoped would help in reducing its numbers along the reefs.”

Bonaire’s divers have probably killed thousands of lionfish in the last couple of years. Last November, 40 volunteers gathered at a bay called Slagbaai and killed 800 lionfish in two days. An American resident on Bonaire boasted to me that in two years he alone has speared more than 2,000 lionfish. “Bonaire is a special place,” De León says. “There are always a lot of volunteers, especially if it’s diving related, so the commitment for sustainable control is here.”

It appears that the persistent hunting has produced results. To measure the effectiveness of Bonaire’s lionfish control program, De León compared Bonaire and neighboring Curaçao, another Dutch Caribbean island. Curaçao did little to prepare for the anticipated invasion and has significantly fewer dive volunteers. The study revealed that Bonaire lionfish are on average 3.5 centimeters shorter and 50 grams lighter than those of Curaçao. Bonaire also has half the number of lionfish of its island neighbor.

By now it has become the classic irony of invasive species control efforts: Wildlife lovers forced to kill some wildlife to save others. And while the volunteer shoot-to-kill programs can be successful, they are not without their downsides. “We’ve spent decades in the Caribbean persuading people that spearfishing is bad. And now, the most effective way to keep the lionfish population in check is to give people some kind of spear,” says De Meyer of the Dutch Caribbean Nature Alliance. “We know that, in a certain sense, it really is counterproductive to the marine environment because it will cause physical damage to the reef. Divers with spear guns are typically focusing on their target, not on the world around them. But it is also counterproductive from a messaging point of view because it’s very difficult to say ‘Yes, it’s good to shoot this.’ and ‘No, it’s bad to shoot that.’ It opens the door to the willfully uneducated.”

That said, De Meyer believes that spearfishing is necessary. “This is a done deal. Lionfish are here to stay. The only thing we can do now is reduce their numbers as much as possible to give the reef fish the opportunity to adapt.”

But divers killing adult lionfish may be only part of the solution. The 2005 Bahamas study reported that reefs with healthy native fish populations have fewer lionfish. De León believes that small-body carnivores like grunts and groupers are targeting baby lionfish when they are vulnerable, about 25 to 40 days after hatching. It also appears that some native reef fish are consuming adult lionfish. While diving in Bonaire this past summer, I watched two divers armed with ELFs being followed by a school of jacks at an unusually close range. When one of the divers speared a lionfish, a jack sped in and snatched the fish off the ELF before the diver could even remove it. De León has also seen this behavior and believes that lionfish toxins are chemically broken down in the predators’ stomachs before they get to the bloodstream, rendering them harmless.

photo of a lionfish closephoto Adam Wimsatt

It remains to be seen if the early success of Bonaire’s control efforts can be applied to other regions. De León is now busy spreading the mantra of lionfish containment through workshops in Curaçao and Colombia. He has also consulted with natural resource managers on Grenada, Barbados, the French West Indies, and the British Virgin Islands.

“We’ve learned a lot since 2009. We know what lionfish like to eat, but we don’t yet know how much they are influencing (native fish) populations. In 2012, we are going to start that study. Still, we’ve taken a precautionary approach to the invasion. We consider lionfish a bad thing for our reefs.”

Back in Florida, Pam Schofield concurs. “Every dead lionfish is a good thing, right? The possibility of eradicating them is very small. It’s just not feasible. However, I think it’s possible in some local areas to control the population if there are commitments from individuals to remove lionfish regularly. It’s a lot like pulling weeds out of your yard. The more you do it, the fewer weeds you will have.”

Schofield pauses, reflecting on recent, troubling reports about other invasive fish that she has received at the Southeast Ecological Science Center. “We need to learn the lessons of the lionfish so that we don’t have another species proliferate. There are at least 30 species of nonnative marine fish that we’ve seen off the coast of Florida in ones and twos. It’s a story that sounds all too familiar.”

Patrick Holian is a freelance writer living in Bonaire. He writes about environmental issues affecting the Caribbean.

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