Invasive lionfish: Some good news at last!


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A new study confirms for the first time that we can fight back against alien lionfish in the Atlantic, leading to the recovery of native fish populations - even if it takes a legion of scuba divers to spear the lionfish one at a time!

Scientists have shown that reducing lionfish numbers by specified amounts – at the sites they studied, between 75-95 percent — will lead to a rapid recovery of native fish in that area, and may have a beneficial effect on the whole ecosystem as a result.

It’s finally a bit of good news in the struggle against this voracious, invasive predator which can eat just about anything smaller than it is. Lionfish can also withstand starvation for protracted periods, so many of their prey species will disappear before they do. Their presence has led to a wipe out of 95 percent of native fish in some Atlantic locations.

Stephanie Green, a marine ecologist in the College of Science at Oregon State University, and lead author on the report published in Ecological Applications said: "This is excellent news. It shows that by creating safe havens, small pockets of reef where lionfish numbers are kept low, we can help native species recover.

"And we don’t have to catch every lionfish to do it."

Which is good — because the rapid spread of these predators in the Atlantic makes their complete eradication pretty much impossible. They’ve also been found thriving in difficult-to-get-to deep water locations.

The latest research used field tests along with computer simulations to determine what percentage of lionfish would have to be removed at a given location to allow for native fish recovery. At 24 coral reefs near Eleuthera Island in the Bahamas, researchers then removed the necessary amount of lionfish to reach this threshold, and monitored recovery of the ecosystem.

On reefs where lionfish were kept below threshold densities, native prey fish increased by 50-70 percent. Some of the fish that recovered, such as Nassau grouper and Yellowtail snapper, are critically important to local economies.

Where no intervention was made, native species continued to decline and disappear.

The model used in this research should work equally well in various types of marine habitat, including mangroves, temperate hard-bottom systems, estuaries and seagrass beds.

But where should future removal efforts be allocated first? Marine reserves, which often allow "no take" of any marine life in an effort to recover fish populations, may need to be the focus, researchers say. The traditional, hands-off concept in such areas may succeed only in wiping out native species while allowing the invasive species to grow unchecked. Keeping lionfish numbers low in areas such as mangroves and shallow reefs is also essential, as they are are hot spots for juvenile fish.

You can read the full report online.

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