Scientific evidence for pain and suffering in crustaceans and cephalopods has grown substantially in recent years, prompting regulatory changes in several countries and challenging assumptions about which animals deserve welfare consideration.
The welfare of aquatic invertebrates challenges our intuitions about which animals matter morally. We readily accept the welfare relevance of vertebrates, but crustaceans and cephalopods have nervous systems sophisticated enough to process noxious stimuli in ways that produce behavioral pain indicators. The precautionary principle — if an animal might be suffering, we should act as if it is — is increasingly influencing legislation. The practical welfare improvements are available: electric stunning of lobsters and crabs before killing is technically feasible and commercially available. The gap is primarily cultural and economic — tradition, cost, and the assumption that these animals do not matter have delayed welfare improvement that science now suggests is warranted.