The native white-clawed crayfish is critically endangered in the UK, displaced by signal crayfish carrying a deadly plague, raising welfare considerations for both species.
White-clawed crayfish infected with crayfish plague die rapidly over days from systemic infection. Signal crayfish in traps experience confinement stress and competing conspecifics before removal or slaughter. The welfare of signal crayfish in management operations must be weighed against the conservation welfare of the critically endangered native species they displace. Humane disposal of signal crayfish and development of species-specific biocontrol are active research areas.