Evaluation of Eradication Success of Northern Snakehead in the Catlin Creek Drainage, NY Using Environmental DNA

Introductions of northern snakehead Channa argus into natural systems are becoming more common in the United States. Before the possession of live snakeheads became illegal, they were a popular import among pet traders and in live fish markets. They exist in the Potomac, Chesapeake, and lower Hudson Watersheds, with small populations present throughout the East Coast of the U.S. When a reproducing population of northern snakehead was discovered in Ridgebury Lake and Catlin Creek near Middletown, New York, the New York State Department of Environmental Conservation (NYSDEC) chose to extirpate them using rotenone pesticide (largely because of downstream connections from this drainage to the Hudson River). We used environmental DNA (eDNA) techniques to determine if previous rotenone efforts to eradicate northern snakehead were successful in Ridgebury Lake and Catlin Creek.  In fall 2013 and spring 2014, approximately 600 2L water samples were taken from within the 8-mile treatment area and as far as 40 miles downstream. Water samples were filtered through glass microfiber filters from which DNA was extracted and screened with species-specific markers using traditional polymerase reaction (PCR). The results of this study, whether positive or negative, will determine future management decisions of nothern snakehead in New York State.