Pre-slaughter stunning for farmed salmon has advanced significantly, with electrical and percussive methods increasingly replacing CO2 immersion and live chilling as the primary welfare intervention at end of life.
Pre-slaughter stunning represents the single highest-impact welfare intervention available at end of salmon life. The shift from live chilling to electrical or percussive stunning reduces the duration of potential suffering from several minutes to less than a second. This represents an enormous aggregate welfare improvement given that over 300 million farmed salmon are killed annually. The key remaining challenges are ensuring stunning effectiveness in field conditions - electrical parameters must be correctly calibrated for fish size - and reducing the stun-to-bleed interval to prevent recovery. Consumer demand for higher welfare certified salmon has been a significant driver of industry change, demonstrating the leverage that purchasing decisions can have.