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Invasive species represent a growing threat to the ecosystems and economies of the United States. The southeastern United States is an aquatic biodiversity hotspot, and the decline of multiple native species already facing extinction is attributed to a rapidly growing number of nonindigenous freshwater fishes. Next-generation sequencing was used to analyze the population genomics of several populations of Pond Loach (Misgurnus anguillicaudatus) introduced to the United States. Three evolutionarily significant units of Misgurnus loaches were found, suggesting the invasion of multiple different species in the United States. Additionally, noninvasive environmental DNA (eDNA) protocol designed for early detection of invasive freshwater fishes, including M. anguillicaudatus and the African Jewelfish (Rubricatochromis letourneuxi), was developed. This eDNA protocol was used to detect M. anguillicaudatus within the Cahaba River Watershed of Alabama to monitor the status and spread of this ecologically detrimental fish. Misgurnus anguillicaudatus were detected in both the most recent samples collected (2024), and in samples collected in 2020, two years before they were first observed in the Cahaba River. These findings demonstrate usefulness of eDNA protocols to monitor and detect invasive species without physical observation, contributing to the preservation of one of the world’s most biodiverse temperate freshwater ecosystems.
