October 17, 2005 - Hundreds of snakeheads have been found in a tributary of the Potomac River in Virginia. Able to breathe air and slither across land for short distances, this predatory invasive species of fish easily threatens native fish species by competing for food and other resources.

The snakehead population in the Potomac River has exploded. During the first half of this year, fisherman caught only 15 snakeheads in the Potomac and its tributaries, but recently they caught 80 in one creek alone. In 2002, more than 1,000 snakeheads were found in a Crofton, Md., pond, the descendants of two imported fish discarded there. State officials poisoned the four-acre lake in an effort to eradicate the colony.

Several National Research Council reports address issues related to invasive species. Predicting Invasions of Nonindigenous Plants and Plant Pests examines the characteristics of non-native plants that makes them likely to become invaders and recommends strategies to improve the ability to predict and prevent invasions. Stemming the Tide: Controlling Introductions of Nonindigenous Species by Ships' Ballast Water assesses whether current controls are stopping nuisance species from entering U.S. ecosystems via ships. Nonnative Oysters in the Chesapeake Bay discusses the risks in introducing disease-resistant Sumine oysters from Asia to offset the decline of native oysters in the Chesapeake Bay.

• Predicting Invasions of Nonindigenous Plants and Plant Pests (2002)
• Stemming the Tide: Controlling Introductions of Nonindigenous Species by Ships' Ballast Water (1996)
• Nonnative Oysters in the Chesapeake Bay (2004)

• Virginia Department of Game and Inland Fisheries
• Snakehead Profile (U.S. Department of Agriculture Informational Page
• Federal Regulations and Laws Pertaining to Invasive Species