The Northern Snakehead, native to Asia, was first caught in a pond in Crofton, MD in 2002. They are a major concern here because they are voracious predators and could impact our native fish species. Their 2002 discovery prompted a rapid response and eradication effort that lead to the removal of over 1,000 juvenile fish. However, in 2004, an established population of Snakeheads was found in the Potomac River. Genetic analysis indicates that the fish have been introduced many times in North America. Because Snakeheads are imported for food and occasionally sold in the aquarium trade, their introductions are likely to be a combination of accidental and intentional (illegal) introductions. Snakeheads have not yet had a significant ecological or economic impact, but the Potomac River population has spread to brackish waters near the mouth of the river and may be moving into other tributaries. In April-July of 2011, several catches of snakeheads were reported in the Bay outside the Potomac River, including St. Jeromes Creek, Nanticoke River, and up the bay to the Rhode and Northeast Rivers. Their spread may have resulted from heavy winter and early spring rains which resulted in unusually low salinities in Chesapeake Bay permitting wider dispersal.