Signal crayfish and noble crayfish are farmed in Europe for food, with welfare concerns around crowding, cannibalism, transport, and live cooking — and invasive species complications for native crayfish.
Crowded crayfish damage each other's appendages, antennae, and eyes through aggression. Moulting individuals are highly vulnerable and require shelter to avoid predation by tank-mates. Transport in crowded containers causes hypoxia and physical damage. Live boiling is the standard slaughter method — scientific literature documents avoidance learning and nociception in crayfish, suggesting this causes pain. Noble crayfish populations face existential welfare and conservation harms from invasive crayfish species interactions.