Northern Snakehead Movement and Distribution in the Tidal Potomac River System

Radio transmitters were implanted in 20 northern snakeheads (Channa argus) in April 2006 to evaluate movement and habitat use of this newly established population. Eight fish were monitored through 15 September 2006, and five transmitters remained active until the conclusion of the study in January 2007. Linear movement was summarized for nine fish frequently found (7-28 contacts; mean 20, SD = 8). Mean movement was 541 m (SD = 356) and the mean “maximum recorded distance” was 2901 m (SD = 2050). Linear movement for fish tracked during the spawning period was significantly different between individuals (ANOVA, P = 0.01), while post spawn movement was not. Northern snakeheads moved more during the post spawn period than during spawning months (March-September). Northern snakeheads showed a habitat preference for hydrilla (Hydrilla verticillata, 24.0%), floating docks (22.8%), and milfoil (Myriophyllum, spicatum, 21.6%) during this study. Regardless of habitats occupied, snakeheads were found exclusively in water less than 1.2 m deep with most contacts made in water less than 0.6 m deep.

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