Stocking density is one of the most critical determinants of farmed salmon welfare, with high densities causing injury, stress, and reduced access to resources for billions of fish annually.
Salmon stocking density directly determines the quality of daily life for hundreds of millions of farmed fish. At high densities, dominant fish monopolize feeding stations, subordinate fish cannot access food normally, fin damage from aggressive interactions increases, and the sensory environment becomes more chaotic. The chronic stress of high-density crowding suppresses immune function and increases disease susceptibility. Lower stocking densities are better for welfare and — counterintuitively — often better for producers too, as healthier fish convert feed more efficiently and have lower mortality. The barrier to voluntary density reduction is short-term economic pressure. Certification standards that set meaningful density thresholds are the primary mechanism for welfare improvement.