End-of-life welfare for farmed trout has historically been poor, with methods causing prolonged suffering. Evidence-based improvements are now available and increasingly adopted.
Fish slaughtered by asphyxiation or CO2 exposure undergo prolonged suffering. The science of fish sentience and pain has advanced substantially, confirming that fish experience aversive states that constitute suffering. Adoption of effective stunning methods - percussion or electrical - before killing eliminates this suffering and represents the single most impactful welfare improvement available at the end of the production cycle.