Where are snakeheads from and how were they introduced?
Northern snakeheads are native to northern China and eastern Russia. Most snakehead species are native to China, though a genus (Parachanna) is found in Africa. Of the nearly 30 snakehead species, the northern snakehead is the only species predicted to be able to survive the North American climate north of Florida and Mexico, though they could survive as far north as Hudson Bay (Herborg et al. 2007). The population in the Potomac River was probably released by an individual who purchased them from a live food market. Although the possession of live snakeheads (all species) has been banned in North America since 2002 (the year a population was discovered in Crofton Pond, MD), the population in the Potomac River was probably released before this data. Analysis of the age structure of fishes captured in 2004 suggests that the population was released around 1998 (Odenkirk and Owens 2005). Genetic analysis of these specimens suggests that few individuals were originally released; 19 of the
