Invasion of the Snakeheads

The voracious "Frankenfish" has turned up in the Potomac River, Lake Michigan and a California lake, sparking fears of an ecological Armageddon

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The scene is a sheriff’s office near a mountain lake, where a hunter and his dog have been found dead. The sheriff sets a bright orange hunting vest on his desk in front of an anxious woman. She nods, identifying it as her husband’s. “He loved that dog,” she says, crying.

“Listen, Norma,” the sheriff says. “If there’s anything at all that I can do, you tell me.”

“You can find the animal that did this and send it straight to hell. You can do that.”

The culprit in the Sci Fi Channel’s made-for-TV movie Snakehead Terror turns out to be a lakeful of monster fish. This star turn is fitting for the toothy “Frankenfish” that has generated many hair-raising newspaper and television news stories—the northern snakehead.

In addition to inspiring filmmakers, the snakehead’s appearance in North American waters in the past few years has worried wildlife biologists and commercial and sport fishermen. They fear that it will invade new rivers, multiply rampantly and edge out other species.

The northern snakehead is native to Asia and is one of 29 snakehead species. It made its national news debut in 2002, after an angler at a pond behind a strip mall in Crofton, Maryland, caught a long, skinny fish, about 18 inches from end to end, that neither he nor his fishing buddy recognized. They photographed the fish before throwing it back; a month later, one of them took the picture to the Maryland Department of Natural Resources (DNR). An agency biologist e-mailed the picture to fish experts, who told Maryland it had a snakehead on its hands.

It was after another angler caught a snakehead in the same pond and netted some babies that all hell broke loose. National newspaper and TV news reports described snakeheads as vicious predators that would eat every fish in a pond, then waddle across land to another body of water and clean it out. A reporter from the Baltimore Sun called it “a companion for the Creature from the Black Lagoon.” The scariest reports, fortunately, turned out to be mistaken. While some species of snakeheads can indeed wriggle long distances across the ground, the northern snakehead—the only species found in the Crofton pond—appears not to be one of them. But northern snakeheads do like to eat other fish, and a heavy rain could conceivably wash one or more from the pond into a nearby river that runs through a National Wildlife Refuge and into the Chesapeake Bay, the largest estuary in North America. To eliminate the snakehead menace, Maryland wildlife officials dumped the pesticide rotenone into the Crofton pond, killing all of its fish. Six adult snakeheads went belly up—as did more than 1,000 juveniles. Problem solved. Or so it appeared.

Two years later, northern snakeheads fulfilled biologists’ worst fear and showed up in the Potomac River. Experts worried that snakeheads in the Potomac, by eating other fish or out-competing them for food, could drive down numbers of more desirable species, such as shad or largemouth bass. You can dump poison in a little, enclosed pond, but you can’t poison the Potomac. It’s a wide, shallow river that originates in West Virginia and runs 380 miles before emptying into the Chesapeake. The bay fuels the region’s economy through recreation and fishing. Snakeheads couldn’t survive in the mildly salty water of the bay, but they could scarf down shad, fish that spawn in the Potomac and other freshwater tributaries. Millions of dollars have already been spent on fish stocking, dam modifications and other projects to help the shad, which used to be plentiful enough to support a commercial fishery in the bay.


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