Developing effective stunning methods for farmed fish before slaughter is a priority area for aquaculture welfare research. Multiple approaches are being evaluated for different species and production contexts.
The welfare case for effective fish stunning before slaughter rests on evidence that fish can experience pain and that unconsciousness eliminates this experience. Current stunning methods vary dramatically in effectiveness - some reliably achieve immediate unconsciousness while others are inconsistent or cause distress before loss of consciousness. Research into better stunning methods is urgently needed given the hundreds of millions of fish slaughtered annually in aquaculture. The economic incentive for the industry is that effective stunning methods reduce stress hormones that affect fillet quality, creating commercial alignment with welfare goals. Consumer and retailer demand for humanely slaughtered fish is also creating market pressure for adoption of better practices.