Cataracts are highly prevalent in farmed Atlantic salmon and cause significant visual impairment and welfare harm, with nutritional and husbandry factors as primary causes.
Salmon cataract welfare is a significant and underappreciated problem in commercial aquaculture. Visual impairment in a predatory fish has cascading welfare consequences: impaired feeding, increased aggression from disorientation, and increased vulnerability to the stressors of farm environments. The high prevalence affects the majority of fish in some farms, making this one of the largest-scale welfare problems in commercial aquaculture. Nutritional solutions and genetic approaches offer pathways to substantial welfare improvement.