Cataract formation is highly prevalent in farmed Atlantic salmon and serves as both a welfare problem and an indicator of nutritional and management deficits in production systems.
Salmon cataract welfare is both a direct welfare problem — vision impairment affects feeding and social behavior — and an indicator of dietary and management deficiencies in the production system. The high prevalence in some farms demonstrates that nutritional optimization for fish welfare has not been prioritized alongside nutritional optimization for growth. The welfare solution is straightforward: adequate dietary supplementation with the amino acids that prevent cataract formation. The fact that this solution is available and not universally implemented reflects the historically low priority given to salmon welfare in commercial aquaculture.