Farmed Salmon Advanced Welfare: Cataracts and Health

Addressing cataracts and other chronic health conditions in farmed Atlantic salmon as indicators of welfare compromise in intensive production systems.

Key Facts

Cataracts affect the majority of farmed Atlantic salmon in some production cycles, with prevalence rates of 80-100% in severely affected cohorts
The condition is associated with nutritional deficiencies particularly histidine in diets, and with environmental stress from UV light exposure
Cataracts cause reduced vision that impairs feeding behavior, increases vulnerability to injury, and is associated with reduced growth performance
The welfare significance of vision impairment in fish depends on how important vision is to the species — salmon rely heavily on vision for feeding
Genetic selection for cataract resistance is being researched as a long-term solution within aquaculture breeding programs
Dietary supplementation with adequate histidine at critical developmental periods reduces cataract incidence significantly

Welfare Considerations

Cataracts in farmed salmon represent a welfare problem that has been partly masked by its widespread acceptance as a production norm. When the majority of fish in a cohort have compromised vision, this welfare deficit becomes normalized rather than addressed. Vision is important to salmon for feeding, predator avoidance, and social behavior — impairment in all of these domains represents ongoing welfare compromise throughout the affected period. The existence of effective nutritional prevention through adequate histidine supplementation means that widespread cataract prevalence is preventable. Industry adoption of better dietary formulations and breeding for resistance reflects a genuine welfare improvement pathway. Consumer awareness that cataract prevalence is a welfare indicator can create market pressure for its reduction.

What You Can Do

Choose farmed salmon from producers with documented health monitoring programs including cataract prevalence reporting
Support certification schemes that include fish health indicators such as cataract and gill disease prevalence in welfare assessments
Advocate for mandatory health and welfare reporting for major farmed fish species including Atlantic salmon
Support research into nutritional optimization and genetic selection programs that reduce cataract incidence in farmed salmon
Reduce farmed salmon consumption or prioritize products from operations with lower stocking densities and better welfare records