Kurt Ingeman is one of several researchers from Oregon State University who has been studying the invasive species' effects on other local fish populations. He recently presented what he called "alarming" research to scientists at the annual meeting of the Ecological Society of America.
The lionfish, a native of the Pacific, was first noticed in the Atlantic in the 1980s. It has since expanded its range there to an area of water larger than the continental U.S.
Whereas most predatory fish hunt only when prey gather in large numbers and minimal effort is necessary to secure a meal, lionfish are undeterred by dwindling numbers. When other hunters move on once a mass of prey has dispersed, lionfish will stick around hunting a local population to depletion.
"Lionfish seem to be the ultimate invader," said Ingeman. "Almost every new thing we learn about them is some characteristic that makes them a more formidable predator. And it's now clear they will hunt successfully even when only a few fish are present. This behavior is unusual and alarming."
Ingeman and his research colleagues watched and observed the hunting behaviors of the lionfish close up -- erecting artificial reefs in the Bahamas and watching the predator feed on fairy basslet, a common aquarium fish and lionfish favorite.
It's not clear exactly what makes lionfish so willing and able to keep hunting even when there's no longer a critical mass of prey. Scientists know they're exceptionally efficient hunters, but they may also go unrecognized as predators by locals.
Ingeman says he's hopeful that local populations can eventually adapt to the lionfish's presence and avoid being terminated.
"There's a strong pressure here for natural selection to come into play eventually," Ingeman said. "We know that fish can learn and change their behavior, sometimes over just a few generations. But we don't have any studies yet to demonstrate this is taking place with native fish populations in the Atlantic."