North America possesses the highest diversity of crayfish in the world, with around 77 percent of the world’s crayfish found there (2). In total, around 308 crayfish species have been described in North America, most of which are found in the south-eastern regions of the U.S (6).
Despite the exceptional diversity of crayfish in North America, there is very little information on the conservation status of most species. However, around 50 percent are thought to be in need of some conservation attention, primarily as a result of their limited range, as well as the alteration of their habitat. Changes to crayfish habitat in the form of dams affects the physical and chemical structure of streams, while the removal of boulders, gravel, wood debris and vegetation can reduce the amount of cover available for crayfish. Without such cover crayfish are vulnerable to predation. Species with a small range are also particularly vulnerable to habitat destruction and degradation by stream channelling, dredging and mining (6).
Declines in spiny scale crayfish populations have been observed in Virginia, due to forestry activities and mining. This species is probably also undergoing some localised population declines as a result of water pollution and alterations to its habitat (1). An additional threat to the spiny scale crayfish is global climate change (1), which may cause some southern areas of the U.S. to become less suitable for species that prefer cooler waters (2).