The method used to stun or kill fish at slaughter has a profound impact on their welfare. Many current commercial practices cause prolonged suffering, but effective and humane alternatives exist and are being increasingly adopted.
Fish experience pain and distress, and the slaughter of billions of farmed fish annually without effective stunning represents one of the largest sources of animal suffering in food production. Asphyxiation, which remains the default method in much of the world, causes a prolonged conscious dying process lasting minutes. The good news is that effective stunning methods exist for most commercially important species and are economically viable. The welfare gap between current practice and best practice is primarily one of adoption, not technology — requiring policy change, industry commitment, and consumer pressure.