Invasion of the Lionfish

BEAUFORT, North Carolina, July 20, 2004 (ENS) - A popular aquarium fish prized for its brilliant colors, the venomous lionfish native to Indo-Pacific waters has established itself off the southeast coast of the United States. Lionfish were introduced just four years ago by releases from aquariums, scientists believe, but the invasive fish already are changing the ecological balance of U.S. coastal waters.

The Indo-Pacific lionfish, Pterois volitans, is the first Pacific marine fish known to populate Atlantic waters, and it is now found around reefs off the southeast coast, says marine scientist Paula Whitfield of the NOAA Center for Coastal Fisheries and Habitat Research in Beaufort.

She will lead a diving expedition next month off the North Carolina coast to learn more about this predatory fish whose population appears to be growing in waters along Florida, North Carolina and Bermuda and as far north as New York.

Indo-Pacific lionfish is multiplying in the deep waters off the U.S. East Coast. (Photo by Paula Whitfield courtesy NOAA)

"These beautiful, but unwelcomed, visitors pose potential risks both to people and to their new marine environment," says Whitfield.

The marine scientists will use remote camera surveys to estimate lionfish densities and allow year-to-year comparisons of native fish diversity and lionfish populations.

Using known lionfish temperature tolerances and bottom-water temperature data, the scientists hope to more accurately predict potential geographic distribution. They will use lionfish specimens to better understand reproductive status, diet, size, age and other genetic information.

Mission coordinator Doug Kesling of NOAA's Undersea Research Center in Wilmington, North Carolina says during each leg of the mission divers aboard the RV Cape Fear will venture out Masonboro Inlet near the research center and travel anywhere from 35 to 100 miles within Onslow Bay, North Carolina to reach habitat that may be colonized by lionfish.

Weather permitting, the RV Cape Fear will stay offshore for five days each week. Some of the sites are known to harbor lionfish, but most are unexplored by SCUBA divers and known only to fishermen, Kesling says.

Most observations of lionfish have occurred in waters more than 100 feet deep. Divers and those fishing in waters at that depth are most likely to have encounters with the fish, Whitfield says.

Lionfish are native to the sub-tropical and tropical regions of the South Pacific and Indian oceans, and the Red Sea, and have few if any natural predators in their new Atlantic environment, Whitfield explains.

Wearing safety gloves, a scientist examines poisonous lionfish spines. (Photo courtesy Stephen Vives/NOAA)

“Dispersal of the lionfish population along the Atlantic coast was likely helped by Gulf Stream transport of lionfish eggs and larvae,” said Jonathan Hare, co-author with Whitfield of a lionfish assessment report published this spring.

“Adult lionfish have been found primarily in water depths of 85 to 300 feet and juvenile lionfish have been observed in North Carolina, Bermuda and as far north as New York in shallow coastal waters,” he said.

“In March, the first known capture of a lionfish by hook and line occurred off the coast of North Carolina," Whitfield said. "The fish was 17 inches long and weighed 2.5 lbs. It’s the largest specimen to date in the Atlantic.”

"There's been little research directly examining the impacts of a marine fish in an open marine system," she said. "We hope our research can lead to improved understanding of the lionfish invasion and its consequences and improve scientific understanding of fish invasions overall."

To report a lionfish sighting, contact Paula Whitfield at 252-728-8714, email: paula.whitfield@noaa.gov