Native white-clawed crayfish and invasive signal crayfish raise different welfare considerations, and management responses must balance conservation of natives against welfare costs to individual invasive animals.
Crayfish have nociceptors and show avoidance learning suggesting pain capacity, though the evidence is less clear than for decapod crustaceans. Signal crayfish drowned in submerged traps experience hypoxic death. Boiling live crayfish without prior stunning causes prolonged thermal trauma if the evidence for crustacean pain is accepted. Humane killing methods including splitting the brain before boiling represent the precautionary welfare approach.