Terror on the Reefs: Venomous Lionfish Invade the Bahamas

November 5, 2010

New Providence Island, the Bahamas—Motoring slowly parallel to the sandy beaches at sunset, aqua seas stretching toward the distant horizon, it's easy to get lulled into imagining I’ve stumbled onto some undiscovered paradise just a day’s float off the coast of Florida.

Until I turn my gaze eastward… The capital city of Nassau sprawls this island’s length, boasting docks big enough to host 14 giant cruise ships.

Comprising 29 islands, including Bimini, Eleuthra and Exuma, the Bahamas are hardly an isolated retreat.

Boasting the third-largest coral reef ecosystem in the world and some monstrous casinos, tourism rules here. The $5 billion-a-year industry employs half the population and makes the Bahamas the most economically prosperous islands in the Caribbean. Its per capita GDP makes it the third-richest country in North America, after the U.S. and Canada.

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Who invited this guy to paradise? (Photo: Carlos Garcia Rawlins/Reuters)

Unfortunately, all that human traffic has created serious environmental issues in these blue-blue seas, including overfishing, coral reef bleaching and acidification.

But since the summer of 2005, the biggest headache in these waters has been one particular fish, a species not usually found in this hemisphere except in high-end aquariums.

Marked by exotic red-and-white stripes and a row of venomous spikes lining its spine, the non-native Indo-Pacific lionfish (pterois volitans) is as big as a football, loves to munch on coral reefs, and for the past few years has been devouring colorful reef fish all along the 1,200-mile Bahamian coastline all the way to the Turks and Caicos.

Theories on how the lionfish reached the Bahamas range from the general (dumped into the Atlantic off the coast of Florida by bored exotic aquarium owners) to the specific (1992’s Hurricane Andrew smashed a specific tank and released a half-dozen of the spiny, venomous fish).

Once outside the confines of four glass walls and far from native predators, the invaders have proven to be insatiable eaters and prolific breeders, wreaking havoc on local fish populations and reefs. The fearsome creatures are also scaring off tourists. Their venom won’t usually kill a human, but the painful sting can cause nausea, convulsions, even paralysis.

The response by the Marine and Environmental Studies Institute at the College of The Bahamas and the Department of Marine Resources, has been to create a “long-term national lionfish response plan” focused on “invasion management” and “educational initiatives.”

But a study by marine biologists Mark Hixon and Mark Albins says a lionfish can kill three-quarters of a reef’s fish population in just five weeks. "In 2005, the first lionfish showed up, and we didn't pay much attention to it," says Hixon, who has studied reef fish here for almost two decades. "The next year, we saw a few more. In 2007, there was a population explosion. There were so many lionfish around that they were eating the fish we were studying, and we had to start studying the lionfish. There was nothing else to do."

Fishermen and divers report them everywhere; spear fishermen have resorted to wetsuits not against the warm waters but the invader’s sting. Dive company owners worry that as the lionfish munch on the reefs and the tourist-attracting colorful fish, the dive business could take a big hit.

(In a recent post, Andy Revkin at The New York Times' Dot.Earth interviewed Maurice “Mojo” White, a Bahamian marine scientist who claims to be leader of a “death to lionfish” campaign and author of the world’s largest collection of lionfish recipes.)

Solutions to exterminating the pests range from putting bounties on their spiky heads to making dumping them in the wild “criminal.”

Back home in the Indian Ocean and South Pacific, the species is most often felled by parasites. Here in the Bahamas, with no natural predators, the fish is tricky to capture or kill.

For the moment, Bahamians are keeping their fingers tightly crossed, hoping a natural predator will emerge from the deep ocean … and soon.