Enhancing Efforts to Control an Invasive Species: The Northern Snakehead

Controlling populations of invasive fish species is an ongoing problem throughout fisheries management.  Sometimes little to no information of the invading species is known or available, therefore hampering control efforts.  The northern snakehead (Channa argus), a species native to Asia, has been established in the Potomac River since 2004.  Efforts to control northern snakehead populations have had varied success since its introduction.  Our goals were to better understand northern snakehead behavior to enhance control efforts.  From spring 2009 to present, we have monitored northern snakehead movement and behavior within the Potomac River by external and radio tagging.  External tagging has shown that an overwhelming majority of individuals (approximately 90%) tend to remain in the same creeks where they were initially captured.  However, those individuals that do move can cover relatively large distances (up to 47 river km).  Seasonal and climatic events appear to drive northern snakehead behavior.  Northern snakehead activity tended to peak within two to five days after periods of high rainfall.  Furthermore, as temperatures dropped during fall and winter, so too did snakehead activity.  This suggests that removal efforts should be focused during times when snakehead activity is low, to increase capture efficiency.  While no obvious negative impacts of the presence of northern snakehead have yet been observed, there should be continued vigilance to deter the spread and growth of this invasive species population.