Stocking density in fish aquaculture is one of the most important welfare determinants. Research consistently shows welfare problems above species-specific density thresholds, yet regulatory limits are poorly developed.
Stocking density is one of the most actionable welfare parameters in aquaculture - it is directly controllable by the producer, is well-studied in relation to welfare outcomes, and is systematically driven too high by economic pressure. Fish in overcrowded systems suffer from fin damage, competitive exclusion from feeding, increased disease transmission and chronic physiological stress. The welfare science supports density limits for specific species - implementing these through certification standards and, ultimately, legislation is the mechanism for translating science into welfare improvement. Consumers who choose certified products at appropriate density limits create the market signal that welfare-conscious production is commercially viable.