Spatiotemporal Patterns and Dispersal Mechanisms of Northern Snakehead in Virginia
Aaron J. Bunch, John S. Odenkirk, Mike W. Isel, and Robert C. Boyce
Abstract.—Concern among stakeholders following the establishment of Northern Snakehead Channa argus in the Chesapeake Bay region is driven by uncertainty surrounding impacts to ecologically and economically important native and naturalized fish and wildlife species and the overall high risk of establishment to other regions of the USA. A centralized statewide database containing all Northern Snakehead observations was used to develop a distribution map. Most fish were collected during research and monitoring studies, while other data sources included verified reports from anglers and commercial fishers. Northern Snakehead have shown a propensity to survive in mesohaline waters (5–18‰ salinity), while polyhaline waters (18–30‰ salinity) likely serve as a barrier to migration during natural migration as evidenced by previous research on upper lethal limits (i.e., 18‰ salinity) and distribution patterns relative to established salinity zone designations in the lower Chesapeake Bay. Illegal introductions into freshwater impoundments have been documented in most major watersheds in Virginia, most recently in the York and James. We encourage biologists, managers, and researchers to take a pro-active and rapid approach in new locations by planning to monitor distribution patterns and offering mechanisms for public reporting and authenticating observations. Most importantly, accurate and evidence-based information must be disseminated to the public and news media outlets including penalties associated with illegal introductions. Targeted research studies to evaluate ecosystem-level impacts will be crucial moving forward.