Farmed Salmon Crowding and Stress

High stocking densities in salmon aquaculture cause chronic stress, aggression, and physiological dysfunction that compromise the welfare of millions of fish.

Key Facts

Commercial salmon farms typically stock 15-25kg of fish per cubic metre of water
High densities increase cortisol levels, suppress immune function, and increase aggression
Crowding prevents subordinate fish from accessing feed, causing stunted growth and poor condition
Norwegian research links high stocking densities to sea lice proliferation
Low-density systems of 10-15kg/m3 show improved welfare indicators and disease resistance
Some welfare certification schemes now specify maximum stocking densities

Welfare Considerations

Stocking density is one of the most powerful welfare levers in salmon aquaculture. The economic incentive to maximise the number of fish per pen creates a systemic welfare problem: fish in crowded conditions experience chronic stress, are unable to express normal swimming and feeding behaviours, and suffer increased disease burden. Reducing stocking densities has measurable welfare benefits and, counter-intuitively, often improves production efficiency through better feed conversion and lower disease losses.

What You Can Do

Choose salmon products certified to welfare standards that specify stocking density limits
Support retailers and food service companies with better salmon welfare commitments
Reduce salmon consumption where certified welfare options are unavailable
Advocate for stocking density standards to be included in all aquaculture certification schemes