The scientific evidence for fish pain and consciousness has grown substantially, with important implications for how fish are treated in aquaculture, fishing, and research.
The scale of potential fish welfare harm is staggering: billions of farmed fish and trillions of wild-caught fish are killed annually, often in conditions that would be considered inhumane for mammals. In aquaculture, crowding stress, disease, handling injury, and slaughter methods that cause prolonged hypoxia or suffocation cause welfare harm measurable by behavioural and physiological stress responses. The evidence for fish sentience is now sufficiently strong that precautionary protection is morally justified. Applying the precautionary principle - treating fish as if they experience pain until proven otherwise - would transform how the fishing and aquaculture industries operate.