MOUNT VERNON, Virginia (Reuters) - They're freakishly strong, hungry air-breathers that can survive for short periods on land. But northern snakehead fish, once viewed as an unstoppable scourge in U.S. waters, may have gotten a bad rap.
So far, they've surfaced in waters from Massachusetts to California, and from Manhattan's Central Park to a pair of creeks in Arkansas. The biggest cluster is in and around the Chesapeake Bay, and officials in Maryland and Virginia have taken different paths to trying to keep them from interfering with the bay's delicate ecological balance.
The threat of the snakehead, which is believed to spawn repeatedly during the year unlike other species that spawn just once, is that it is such a hardy newcomer that it could squeeze out longer-established and more desired fish.
Native to China's Yangtze River basin, the so-called "frankenfish" made its first big media splash in the United States in 2002, when a thriving population was discovered in a Maryland pond outside Washington.
Known taxonomically as Channa argus or "lightning perch," they were purported to be able to "walk" on land, to wipe out native species and to have no natural predators.
Plenty of other non-native fish have thrived in the United States, but few rival the northern snakehead: as long as 30 inches or more, the fish has a large, toothy mouth and can survive for days out of water, squirming and secreting a full-body slime. It is a delicacy in Asia and is gaining a following among chefs in the United States.
Virginia fisheries biologist John Odenkirk said intelligent management - not eradication - of the snakehead is his state's goal. So far, the fish have not wreaked havoc with the Potomac River ecosystem, he said on a recent survey trip through Virginia streams.
The snakehead population has risen since 2004. But so has the population of large-mouth bass, a prized regional sport fish that brings in $622 million a year to Virginia and accounts for more than 5,500 jobs in the state, according to the American Sportfishing Association.
"That is one tough fish," Odenkirk said as he pulled in a thrashing, 32-inch long snakehead with an apparent knife gash in its abdomen. The biologist figured the cut was a few days old, probably made by an angler who tossed the wounded fish back into the water. He caught the fish in an estuary of the Potomac, not far from George Washington's estate at Mount Vernon.
"As badass as they are, I just don't think he's going to make it," Odenkirk said of the male snakehead, whose entrails protruded from the 5-inch cut. Even so, it continued to breathe and move normally.
Reports that the dreaded snakehead had invaded the Harlem Meer in New York's Central Park in April prompted a warning by the state's Department of Environmental Conservation: "If you catch one, DO NOT RELEASE IT. Kill it immediately, freeze it and report your catch."
A similar warning is posted on Maryland's Department of Natural Resources website.
Maryland manages the snakehead differently than Virginia, which prohibits commercial sales to avoid creating a market for the fish. Maryland encourages sales, maintaining that eating snakehead gives other fish a chance.
John Rorapaugh, director of sustainability at ProFish, a Washington seafood wholesaler, said his company pays $4 to $5 a pound for snakeheads, compared to $.50 to $1 for catfish.
The snakehead's mild flavor and firm texture make it a chef's favorite, he said.
Snakeheads' numbers are increasing, even as myths about them are dispelled. Media reports of them "walking" are exaggerated, though they can slither onto land.
And Odenkirk dismissed the notion that they have no natural predators. Snakehead young, if left unguarded, are easy prey for ospreys and eagles, he said.
Odenkirk said it is still unclear how damaging snakeheads are to their U.S. environments. Paul Angermeier, a fisheries research scientist at the U.S. Geological Survey, agreed.
"It's still quite early," said Angermeier, who is based at Virginia Tech. "A decade or so isn't long for an invading population to really wreak havoc on things." So far, that hasn't happened, he said.
Reporting by Deborah Zabarenko; Editing by Marilyn W. Thompson and Philip Barbara