AMG HIGHLIGHT
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A new study based in the Bahamas showed that killing 75% of the lionfish population on reefs dramatically increased native fish populations. With the fish being relatively easy to catch, lionfish culls may be a lucrative – and beneficial – addition to tourist attractions
It is unclear where the first Caribbean lionfish came from, but they may have escaped when a restaurant aquarium in Florida was destroyed by Hurricane Andrew in 1992. Or they may have been introduced by aquarium lovers in the 1980s. However they got there, the striking fish have been wreaking havoc in the Caribbean and the Gulf of Mexico.
Scientists throughout the Caribbean are reporting seeing large, and growing, densities of lionfish, and estimate that their range now covers 3.3 million square kilometers of the Atlantic. Smaller reef fish have experienced declining populations in the last four years, with juvenile fish falling prey to the invasive species.
And while the decline hasn’t yet reached the older, larger fish, it will likely be seen in the next several years when the decimated juvenile population matures.
A unique threat in Caribbean waters
The lack of natural predators, along with the lionfish’s predilection for consuming coral reef dwellers, has made the species thrive and spread throughout the Caribbean.
Oscar Lasso, an icthyologist with the La Salle Foundation of Natural Sciences in Venezuela, says that the lionfish “preferentially inhabits coral reefs, where it waits for other animals that do not even recognize it as fish, opens its mouth and eats everything that goes by.” A lionfish’s stomach can expand to 30 times its normal size, allowing the animal to eat huge amounts of food.
The red lionfish can reach around 45 cm in length (they grow larger in the Caribbean than they do in the Pacific), and has reddish and white stripes. The fish themselves are solitary predators of crabs, shrimp and small fish, which they stalk and kill with a quick snap of their powerful jaws.
Control efforts
With there being no known natural lionfish predators, divers in The Bahamas and Barbados have taken to dangerous shark-feeding experiments to entice predators to gain an appetite for the fish.
[videoembed type=”youtube” url=”https://www.youtube.com/watch?v=Kactuybws1k”]Attempts are also underway to control the lionfish population by popularizing it as a menu item for humans. They’re extremely easy to spear – as they aren’t used to evading any predators – and in The Bahamas, the fillets can sell for around eight dollars a pound, cheaper than grouper or snapper. Fisherman Carson Colmar says he catches about fifty per week to sell at the Nassau waterfront market.
Emerging research
A new study of Bahamian reefs, led by Stephanie Green of Oregon State University, sheds some hope. Her team found that killing between 75 and 95 percent of a reef’s lionfish population can increase native fish populations by 50 to 70 percent within 18 months. And while killing 75 to 95 percent of the fish sounds like a daunting task, divers find it relatively easy to kill 75 percent of lionfish on any given reef.
In their native habitat, stretching from the east coast of Africa to the west coast of Australia, lionfish do not destroy the reef ecosystems like they do in the Caribbean. It’s unclear why there is such a striking difference between the two lionfish populations, but this new research provides some hope that the Caribbean reef ecosystems could be salvaged.
Image credit: Antje Schultner
