Native white-clawed crayfish face extinction from North American signal crayfish that carry crayfish plague, destroying populations across UK rivers and lakes.
Crayfish infected with plague show rapid neurological deterioration; mortality is total within days of exposure. While crayfish sentience is uncertain, precautionary concern is warranted. The ecological collapse caused by signal crayfish removes a keystone invertebrate that supports fish, otters and waterbirds, with cascading welfare effects throughout the freshwater community.