Meta-genomic surveillance of invasive species in the bait trade

There are a number of different pathways by which invasive species can enter aquatic ecosystems, including the relatively unstudied live bait trade. Through contaminated stocks, the bait trade vector has the potential to distribute species widely, and unknowingly, across a wide geographic area. These introductions can have large implications for the conservation of native biodiversity and habitats. Reliable techniques for monitoring for invasive species remains challenging, particularly due to a lack of taxonomic expertise by those using live bait. Here, we show that non-target species (i.e., rare; not intended to be purchased) can be detected based on environmental DNA (eDNA) collected in water samples from commercial bait vendors. Utilizing high-throughput DNA sequencing, we analyzed water samples collected from six different commercial bait shops, screening the resulting sequence data for presence of non-target, and potentially invasive species of fish. Our findings show that DNA from multiple non-target species was present in the collected samples, including DNA from at least one potentially harmful invasive species. Additionally, this work supports the use of eDNA surveillance for screening the bait shop vector for rare and potentially harmful aquatic invasive species.