SUMMARY
Non-indigenous species are a significant threat to freshwater biodiversity. In the Potomac Basin there are several known invasive crayfish species including F. virilis (virile crayfish) and F.rusticus (rusty crayfish). It is imperative to discover whether F. obscurus is in fact an invasive crayfish that needs a management plan or simply another native species that needs protection. F. obscurus is a wide-ranging crayfish species that is native to the northeastern United States. Populations found in the Atlantic Slope Drainage basins are considered invasive. Using CO1 and 16S primers, we will be creating a range-wide haplotype map to investigate these invasions.