Control of the lion fish
A recent Oregon State University study shows that controlling the invasive lionfish in the western Atlantic Ocean is likely to allow for recovery of native fish. The lionfish is estimated to have wiped out 95% of native fish in some Atlantic locations. This Atlantic invasion is believed to have begun in the 1980s and now covers an area larger than the United States.
With venomous spines and aggressive behavior, the lionfish has no natural predators in the Atlantic Ocean and will eat almost anything smaller than they are including fish, shrimp, crabs and octopus. Lionfish can withstand starvation for protracted periods; many of their prey species will disappear before they do.
OSU and Simon Fraser University scientists have shown in both computer models and 18 months of field tests on reefs that reducing lionfish numbers by specified amounts, between 75-95%, will allow a rapid recovery of native fish biomass within the treatment area, and may aid larger ecosystem recovery to some extent as well. The researchers have learned that the solution will be found in controlling the lionfish either by creating safe havens for other fish or spearing one lionfish at a time.
"This is excellent news," said Stephanie Green, marine ecologist in the College of Science at OSU, and lead author on the report published in Ecological Applications. "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."
Researchers acknowledge that the rapid spread of lionfish in the Atlantic is virtually impossible especially considering that they have now found the lionfish thriving in difficult to access deep water locations.
The latest research used ecological modeling 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 the Bahamas' Eleuthera Island, researchers removed the necessary amount of lionfish to reach their modeled threshold and monitored the ecosystem recovery.
On reefs where lionfish were kept below threshold densities, native prey fish increased by 50-70%. This study demonstrates that reduction of an invasive species below an environmentally damaging threshold versus eradication can have comparable benefits.
Some of the fish that recovered, such as Nassau grouper and yellowtail snapper, are critically important to local economies.
Read more at Oregon State University.
Lionfish opening wide image via Shutterstock.