Stocking density in farmed Atlantic salmon sea cages significantly affects welfare through its effects on behaviour, fin damage, disease, and stress responses.
Stocking density is one of the most important and modifiable welfare determinants in salmon aquaculture. High density causes chronic stress, reduced ability to maintain social distances, increased aggression, and suppressed immune function. Lower density operations demonstrate that commercially viable salmon farming can maintain better welfare, with benefits including reduced disease and antibiotic use that align welfare and economic incentives.