The feed used in salmon farming has major implications for fish welfare, wild fish populations, and environmental sustainability of the aquaculture industry.
Feed composition directly affects salmon welfare in aquaculture. Diets deficient in key nutrients cause preventable suffering: tryptophan deficiency increases aggression and fin-biting; vitamin C deficiency causes spinal deformities; inadequate pigment sources affect light sensitivity and visual health. Plant-based protein substitutes can reduce palatability, leading to reduced feed intake and slower growth associated with chronic hunger. High-density farming combined with suboptimal nutrition creates cumulative welfare stress. The sourcing of fishmeal also has welfare implications — small forage fish used for fishmeal are caught in vast quantities and often processed while alive. Improving feed nutrition standards protects both farmed salmon welfare and the ecosystems supporting the industry.