Sea lice are the most significant parasite burden in Atlantic salmon farming, causing tissue damage, immune suppression, and pain that represents a major welfare challenge in the industry.
Sea lice infestation causes genuine pain and suffering in farmed salmon. Research has confirmed that salmon possess nociceptors and behavioral responses consistent with pain experience. Open lesions from severe infestations expose fish to secondary bacterial and fungal infections. Treatment procedures themselves — handling, freshwater bathing, mechanical removal — cause acute stress. The most welfare-positive approach combines early lice detection through regular monitoring, preventive measures like deep feeding strategies and lice skirts, and rapid treatment when thresholds are exceeded — minimizing both infestation suffering and treatment stress.