Lionfish Off Coast Could Threaten Fishing

August 19, 2004

Release from: NewsObserver.com

WILMINGTON, N.C. - When divers first reported lionfish off the North Carolina coast four years ago, biologist Paula Whitfield thought it must be a mistake or an aberration.

The poisonous, carnivorous Indo-Pacific lionfish is native to tropical waters half a world away - not the seas off the Outer Banks.

An ongoing study has shown Whitfield that things are worse than she could have imagined. The fish is not only present but thriving, and could threaten important commercial fish species such as snapper, grouper and sea bass.

"They're everywhere," she said Tuesday as divers brought another two lionfish aboard the University of North Carolina at Wilmington research vessel Cape Fear.

Whitfield, a fisheries biologist with the National Oceanic and Atmospheric Administration, is leading a team that has been diving about 50 miles southeast of Wrightsville Beach.

The expedition, sponsored by NOAA's Undersea Research Center at UNC-Wilmington, is meant to see how extensive the invasion by the lionfish is and what effect it might be having on native species.

Whitfield said researchers were hoping to find 30 specimens, but have already hauled up nearly 80 with a week of dives still to go.

The disheartening results could mean dropping efforts to eradicate the fish and instead developing a plan to manage them.

"It wouldn't be bad if we were just finding adults," research center science director Tom Potts said. "But now we're finding juveniles and pregnant females as well."

The fish is the top predator in its native Indian and South Pacific ocean habitats - a role filled by the grouper and snapper in local waters. It has no known natural enemies.

A worrisome note is that the reefs and hard-bottom areas it favors locally are also the nursery grounds for important commercial and sport fish, such as snapper and grouper.

"We now know they're eating fish, not crustaceans or other shellfish," Whitfield said aboard UNC-W's research vessel Cape Fear, as NOAA research technician Christine Addison removed a small jar from a cooler containing three young sea bass found in a lionfish's stomach.

Little is known about the lionfish's breeding pattern, but scientists believe it can spawn several times a season.

Addison, holding a full ovary from a fish she was dissecting, said each female can release between 5,000 and 20,000 eggs each spawning.

The way the eggs are dispersed could explain the lionfish's rapid colonization of reefs and hard-bottom areas between Florida and Long Island, N.Y., she said.

They are buoyant, and could ride the warm waters of the Gulf Stream all along the Atlantic seaboard _ one way lionfish or their eggs might have migrated up the coast from Florida, where many researchers think the first aquarium releases occurred.

"This fish seems to have everything going for it," she said with a wry smile.

Whitfield said lionfish have been found only in areas of warm water, with temperatures from the mid-60s or higher, in depths ranging from roughly 120 feet to an estimated 260 feet.

"That means they probably won't get any closer than maybe 25 miles offshore," she said.

But that leaves a huge swath of ocean for the lionfish to colonize.

"We've found them at 10 of the 12 places we've dived at, and in large numbers," Whitfield said.

Researchers plan to conduct more dives this winter to see how the lionfish manage off the Cape Fear coast as water temperatures drop. Whitfield also said she hopes to do some fish tagging and additional census data to gauge the newcomer's density and geographic range.

But she said she can already draw one conclusion without any additional research.

"I think they're here to stay," she said. "Unfortunately, that's something we can now say pretty confidently."