Mortality rates in farmed salmon have increased in some producing regions due to sea lice infestation and disease, representing both a welfare crisis and an economic problem driving welfare improvement investments.
Salmon mortality from disease and sea lice represents one of the most significant welfare crises in commercial aquaculture. Fish experiencing sea lice infestations suffer direct tissue damage, chronic immune stress, and increased vulnerability to secondary infections. Treatment methods - including warm water baths and mechanical cleaner fish - provide relief but carry their own acute welfare costs. The mortality that results represents fish experiencing disease suffering until death. Systemic solutions including closed containment systems, breeding for resistance, and improved lice management protocols offer welfare improvement at scale, aligning with economic incentives for the industry.