Sea lice infestations in farmed Atlantic salmon cause chronic pain and skin damage, with control strategies balancing welfare, environmental impact, and efficacy across chemical and biological approaches.
Sea lice represent one of the most significant and chronic welfare challenges in Atlantic salmon farming. The wounds created by lice feeding are visibly painful and cause behavioral changes consistent with nociception. High lice burdens impair the fish's ability to regulate salt and water balance causing physiological stress beyond the direct tissue damage. Treatment procedures themselves cause acute stress and injury risk. The economic pressure to maintain production creates incentives to tolerate higher lice levels than welfare science would endorse. Progressive reduction of chemical treatment through biological control and selective breeding offers a path toward better welfare outcomes.