Snakehead photograph courtesy of USGS

When the first of the northern snakeheads, the Asian exotic fish that can breathe air and survive for short periods on land, was plucked from a Crofton, Maryland pond in the summer of 2002, it catapulted onto David Letterman's Top Ten list and grabbed the nation's collective consciousness. Now the infamous fish is back in the Chesapeake region and it could be settling in to stay.

Troubles began again on April 26, when an angler snared a 19-inch, female snakehead from a pond in Wheaton, Maryland. Over the next week, the Maryland Department of Natural Resources (DNR) drained the pond but did not find other fish.

Any sigh of relief was short-lived, however, and the following weeks have brought further cause for concern. On May 7, a fisherman landed an immature female snakehead from Little Hunting Creek, a tributary of the Potomac River in Virginia. Later in the week, another angler pulled up another female on the nearby Maryland side of the Potomac, in Charles County. And a few days after that, a participant in a bass fishing competition snagged a third snakehead, of a similar size, from a site along the Potomac about 10 miles downstream from Little Hunting Creek. Maryland DNR has posted emergency snakehead fish warning signs along the Potomac. The agency is encouraging fisherman who catch them to kill them and to expeditiously report findings to the authorities.

Unlike ponds, which can be drained, the Potomac River is a system of interconnected waterways that stretches for 280 miles. "From a management standpoint, finding the fish in an open body of water certainly elevates the level of concern," says Andy Lazur, an aquaculture extension specialist from Maryland Sea Grant Program, who served on the Maryland Snakehead Scientific Advisory Panel in 2002. "And if the fish does become established, managers will have to manage around the fish. And there are limited tools available," he says.

But finding a few snakeheads in the Potomac does not mean that a reproducing population has established. "Three fish, a population does not make," cautions Paul Shafland, director of the Non-Native Fish Research Laboratories of the Florida Fish and Wildlife Conservation Commission in Boca Raton, Florida. "Three fish out of the same and adjacent systems does certainly raise your eyebrows, but it is important to confirm the existence of a population before jumping to any conclusions," he says.

Some believe that the evidence is already fairly compelling, however. "Snakeheads are probably already pretty widespread in the system," says fisheries biologist and snakehead specialist Walter Courtenay from U.S. Geological Survey's Florida Integrated Science Center in Gainesville. The larger fish caught in Wheaton is of a different size and age class than the three caught in the Potomac, and these bodies of water can all be linked together geographically which suggests that there might be a reproducing population, he says.

But even if the snakehead is here to stay, the effect of a new predator in the food web will take years to understand and, in the end, may not have a catastrophic ecological impact. "Freshwater fish communities are far more plastic and resilient than we would expect," says Shafland. "An introduction of a freshwater exotic is more akin to ecovandalism than ecoterrorism," he says. In addition, other predators in the system, such as large-mouthed bass may actually consume snakeheads. According to Lazur, "There is no way to predict how these fish will respond as both predator and prey in the system. It remains to be seen."

Whether or not snakeheads live up to their "Frankenfish" profile in the media, they have become poster children for communicating the risks of introducing exotic species to the environment. "If there is one take-home message from the snakehead introduction," says Shafland, "it is that it is the public's responsibility not to release exotic species into the wild. It is illegal and it is inhumane for the animal. We need to take this seriously," he says.

- Erica Goldman

Northern Snakehead Weblinks

• Snakehead profile
  http://www.invasivespecies.gov/profiles/snakehead.shtml
• Washington Post Webcast with Andy Lazur
  http://www.washingtonpost.com/wp-dyn/articles/A36762-2004May18.html
• Have You Seen This Fish?
  http://www.dnr.state.md.us/fisheries/fishingreport/snakehead.html

Snakehead photograph courtesy of USGS

This page was last modified June 08, 2004

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