Reviewing evidence for crayfish sentience and nociception and what this means for their welfare in aquaculture and research.
Crayfish welfare sits at the scientific frontier of sentience research. The evidence for decapod sentience - anxiety-like states modified by anxiolytics, avoidance learning, wound-guarding behaviour - is compelling enough to have changed UK law but remains debated. The welfare precautionary principle argues that where sentience is plausible and the cost of welfare improvement is low, protection should be extended rather than withheld pending certainty. For crayfish, this means reconsidering the routine use as live bait and developing humane killing methods for aquaculture.