The Northern Snakehead, Channa argus, is an invasive fish species in North America with populations initially established in mid-Atlantic water bodies. Its presence was first recorded in the United States in 1997. The species was listed as a highly injurious species in 2002 under the Lacey Act. Since those earliest captures, additional observations of this species have been found in waterbodies of Georgia, Louisiana, Mississippi, Missouri, and Arkansas (USGS 2024). Establishment of Northern Snakehead in the United States is largely due to species behaviors and characteristics: tolerance to a wide range of water temperatures, a swim bladder that can act as a primitive lung allowing the species to survive in low oxygenated waters or no water for multiple days, high fecundity, and its aggressive feeding habits. These characteristics adversely affect native aquatic species’ ability to compete for food and habitat (Fuller et al., 2019).

The U.S. Fish and Wildlife Service (USFWS) has monitored populations of Northern Snakehead in a variety of locations of the mid-Atlantic United States using eDNA samples since 2019. Expansion of observed Northern Snakehead populations into portions of the Mississippi River watershed in recent years has created a need to explore eDNA monitoring methods for Northern Snakehead in new areas of the U.S.

The USFWS Whitney Genetics Laboratory (WGL) and Northeast Fishery Center have each completed laboratory validations of two Northern Snakehead eDNA assays and successfully established assay repeatability across laboratories and platforms. The goal of the present study was field validation of two Northern Snakehead eDNA assays using environmental water samples collected from presumed snakehead occupied and negative sites in Arkansas.