Carl was a guest blogger on Mark Bittman’s column on NY Times.com. This was originally posted on August 22, 2012.
About 20 years ago, one of the world’s most beautiful and otherworldly fish, the lionfish, started showing up in south Florida and the Caribbean. Now, they’re—let’s face it—they’re a plague. Millions of them now live from the northeastern South America to New York, in water you can stand in, down to depths of a thousand feet.
In a world where the main concern about fish is overfishing, and the main demand on fish is to feed an increasingly hungry human-dominated world, it may see odd to complain about abundance. But theirs is an abundance that produces widespread scarcity. That’s because invaders from afar often crowd out or gobble a wide array of desirable natives. And as an invading saltwater fish—the lion is king.
Several things: Lionfish are native to the west Pacific, Indian Ocean, and Red Sea. Lionfish are quilled with venomous spines. The sting is not fatal. But from the descriptions I’ve heard of the pain, victims might wish it were. (Yesterday while working underwater with a scientist I got barely nicked through a glove; it produced an immediate sensation and a bump).
Lionfish are here in the Atlantic, it seems, because of owners of living room aquariums who tired of the upkeep but didn’t want to kill their fish. With compassion in their breasts, they released them, in numbers sufficient to get them established. Then—remember the phrase, “balance of nature?” Well—.
No native fish in the Atlantic looks like them, hunts like them, or stings like them. Result: No native fish in the Atlantic recognizes them as a predator. No native fish in the Atlantic gets alarmed when lionfish are on the “hunt,” because a hunting lionfish looks like a drifting piece of seaweed. And no native predator—sharks, say, or barracuda—wants anything to do with those venomous spines.
And so, as I said, there are millions of them. The problem: they’ll eat anything in sight. Forty-plus kinds of native fishes have been found in their bellies, including the young of fishes like snappers and groupers and others of commercial, ecological, and culinary value. They eat juvenile surgeonfishes and parrotfishes that, crucially, graze algae off of reefs and make it possible for baby corals to get established and grow.
Atlantic coral reefs are in a world of hurt as is. The most formerly abundant corals have collapsed throughout the Caribbean, thanks to new diseases, pollution, silt, overfishing, over-warming, and acidifying seawater (the same combustion-produced carbon dioxide that causes climate warming dissolves in seawater to form carbonic acid, hampering growth of corals and edible shellfish).
As corals die, seaweed takes over. Where seaweed takes over, baby corals can’t grow. One of the only hopes for the reefs is the recovery of fishes—especially parrotfishes—that graze-off the seaweed that is smothering many reefs. Reefs can’t afford a new predator that has no predators and that eats all the babies of the fish that graze. They can’t afford lionfish.
We’ve come to the Cape Eleuthera Institutein the Bahamas, where professor Mark Hixon of Oregon State University is studying the effects that
lionfish have on native reef fishes. On our first dive, on a patch of reef a mere 50-feet across, we counted 21 lionfish—and very few of the fish that lionfish eat.
On reefs where Hixon’s students are removing lionfish—more fish of various kinds seem to be surviving.
Hixon is finding that if you want to get rid of lionfish, you basically have to remove them one-by one. People who like their reefs are, in fact, organizing groups of spear-fishing divers to do just that. Other people are trying to commercialize lionfish, hoping to make them the next big flash in the pan. Over the next few days, in the course of filming an episode for an upcoming PBS television series called Saving the Ocean, we’ll be seeing the lionfish’s human adversaries in action.
Will they send lionfish the way of cod, tuna, groupers, snappers, and other overfished ocean wildlife? For now, after 20 years of working against overfishing, I’m betting on the power of fishing people to deplete their targeted prey.
If you can’t beat ‘em—join me for my next post as divers at a lionfish derby in Florida go on the counterattack.