Salmon feed composition affects both fish welfare and ocean sustainability. As wild fish meal is replaced by plant and insect proteins, understanding the welfare implications of nutritional transitions is increasingly important.
Feed quality is a direct welfare determinant for farmed salmon — nutritional deficiency causes disease, immune compromise, and competitive feeding behaviour that increases aggression injuries. The transition away from fishmeal toward plant and alternative proteins must be managed carefully to avoid nutritional gaps that affect welfare. Cataract development — a condition affecting significant proportions of farmed Atlantic salmon — is a welfare harm linked to dietary histidine insufficiency and is preventable through appropriate feed formulation. Feed palatability and presentation also affect welfare: uneaten feed that decomposes in pens reduces water quality; feed presentation that spreads distribution reduces competitive aggression. Welfare-optimal nutrition is simultaneously good for fish and production efficiency.