America’s elusive crayfish and the eDNA that’s finding them
Signal crayfish are displacing Shasta crayfish. Believed to have already forced the sooty crayfish (Pacifastacus nigrescens) to extinction, signal crayfish have outcompeted their Shasta cousins to near extinction. However, a growing trend of environmental monitoring, typically referred to as eDNA, is helping scientists isolate the scarce species in an effort to save it.