WASHINGTON — They may be exotic, but around these parts, they're nothing but common criminals.
There are wanted posters with unflattering profile shots. There's the risk of jail time for harboring one of the outlaws, a modest bounty for turning one in and the damning description being circulated for miles around: "small head," "large mouth," "big teeth."
The northern snakehead, a fish native to Asia, has been busted here before. But like a sequel to a cheesy horror movie, it has returned in ever-greater numbers -- and its presence could cause havoc for the region's aquatic ecology.
Since early May, at least 16 northern snakeheads have been pulled out of the Potomac River and its tributaries. Anglers and biologists alike now fear the worst: that the voracious fish with canine-like teeth and a snake-like ability to wriggle on land for days at a time, breathing air, has established permanent residency here.
"I do think we have a serious problem," said Walter R. Courtenay Jr., an ichthyologist and retired Florida Atlantic University professor nicknamed "Dr. Snakehead" by his colleagues. But, he added, "I don't think there's anything that needs to cause any hysteria."
By now, the story of what happened at a tiny pond in Crofton, Md., two summers ago is part of Washington-area lore.
A local man bought a pair of northern snakeheads from an Asian fish market in New York to make some soup for an ailing sister; freshly killed, the fish are reputed in some cultures to have healing powers. But the snakeheads, which can reach three feet or more in length, quickly outgrew their welcome -- and instead of using them for soup, the man dumped them in a pond behind a Dunkin' Donuts in early 2000.
In May 2002, a fisherman dropped by a government building in the state capital, Annapolis, with a photo of a fish he had recently caught in Crofton but couldn't identify. Courtenay, who has spent more than three decades studying nonnative fish species, was called in to help.
His first reaction: "Uh-oh, this is not good."
It was a northern snakehead -- distinguished for its ability to survive in environments from the tropics to Siberia and notorious for its indiscriminating palate. Biologists poisoned the four-acre pond with the insecticide rotenone. By the time they were done, six adult snakeheads and about 1,000 juveniles were found belly-up. State officials declared a victory.
For about two years, all was quiet. But in April, a fisherman reeled in a 19-inch snakehead from a pond in Wheaton, Md., about 30 miles from Crofton. Biologists responded by sucking the five-acre pond dry; no more snakeheads were found.
Then in May, they returned -- with a vengeance. Not only were there more of them, but they were being pulled from a 14-mile stretch of the Potomac River, an open body of water 395 miles long and seven miles wide at its mouth, where it pours into Chesapeake Bay.
The snakehead is no longer just a big fish in a little pond, and investigators aren't sure what to do next. "You certainly can't drain the Potomac and you can't poison it," said Courtenay, who once again is advising state officials.
The northern snakehead does not travel in packs and it does not attack humans -- that's its cousin, the giant snakehead. But biologists and anglers are concerned that the fish, which when fully grown has no natural predators, will gobble up everything in its path in the Potomac, including native species like largemouth bass, sunfish, white perch and striped bass.
The snakehead's concentration in just one section of the river, Courtenay said, results from the presence of two species of nonnative aquatic plants that provide an ideal habitat. The fish is not expected to spread downstream to Chesapeake Bay and beyond because it doesn't thrive in salt water.
But before they concede defeat to the creature dubbed "Frankenfish" and a "pit bull with fins," environmental officials are waiting for a final determination that the snakeheads are, in fact, reproducing. So far, none of the fish caught in the Potomac has been a juvenile, and the Smithsonian Institution has not completed DNA tests to determine whether any of them are related.
But the circumstantial evidence is mounting: It's spawning season, and three of the females that have been nabbed were carrying unfertilized eggs. Some fish have been observed with another snakehead hovering nearby -- a mate, perhaps. And the growing number that have turned up suggests it's unlikely that each was dumped into the river separately.
After snakeheads made their initial splash in the Washington area two years ago, Interior Secretary Gale A. Norton banned the importation and interstate sale of all 26 species of snakeheads, including the northern variety. A grocer in Los Angeles' Koreatown was arrested in May on three federal counts of illegally importing live "injurious fish" after wildlife officials saw snakeheads at his market on West 8th Street.
