From molluscs to echinoderms, aquatic invertebrates are increasingly studied for their capacity to experience pain, stress, and wellbeing.
Extending welfare consideration to aquatic invertebrates challenges our intuitive categories of who deserves moral concern. The evidence base is strongest for cephalopods and decapod crustaceans, where behavioral and neurological data support the likelihood of pain experience. For other invertebrate groups, the picture is less clear but warrants precautionary consideration. The scale of invertebrate use in fisheries, aquaculture, laboratory research, and the pet trade is enormous — billions of animals are affected annually — which means even a small probability of sentience across these groups represents potentially massive amounts of suffering or wellbeing. Welfare science is advancing faster than regulatory frameworks, and proactive moral consideration now helps build more humane systems for the future.