Lionfish Continue To Plague Caribbean Ecosystems, But Threat Can Be Controlled
The Caribbean's lionfish invasion may be "the worst environmental disaster the Atlantic will ever face," but new research out of the Bahamas finds that the threat may be manageable. Led by marine ecologist Stephanie Green of Oregon State University, the study found that ecosystems ravaged by lionfish can be saved if lionfish numbers are kept in check. Total eradication of the lionfish, in other words, is not necessary.
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"[B]y creating safe havens, small pockets of reef where lionfish numbers are kept low, we can help native species recover," said Green. "And we don't have to catch every lionfish to do it."
Using data collected from 24 coral reefs in the Bahamas as well as computer simulations, Green and her team found that killing between 75 to 95 percent of lionfish from a reef results in an increase of 50 to 70 percent of native fish species like grouper and snapper within a year and a half.
Of course, that's a lot of lionfish to have to kill. But Green said that divers are able to catch 75 percent of lionfish from a reef relatively easily; after that point "it is diminishing returns, and you spend a huge amount of time getting those last few individuals. That time is better spent moving to a new site and starting over." So in theory, as long as divers can get that first 75 percent of lionfish from a reef, that would be enough for native fish species to recover in "safe haven" reefs. Until now, the school of thought has been that removing 100 percent of lionfish from reefs--a fairly impossible task--was necessary to quash the threat.
Lionfish are truly dastardly creatures. The fish are invasive to the Atlantic, where they have no natural predators (they are even fearless in the face of sharks). They spawn every three to four days. They are "gape-limited," meaning they can only eat what fits in their mouths, but they'll eat pretty much anything that does. It should come as no surprise that the little devils' spikes are venomous.
Lionfish are native to the east coast of Africa to Australia, where they don't destroy ecosystems like they do in the Caribbean. "We don't know why they aren't a problem there," said Green. "It could be something there eats them as juveniles or eats their eggs, or that they are not as effective predators." Lionfish began to appear in the Atlantic Ocean in the 1980s, possibly the result of aquarium lionfish somehow getting into the ocean.
Green's study, "Linking removal targets to the ecological effects of invaders: a predictive model and field test," was published in in the journal Ecological Applications.
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