Sea cage salmon farms near wild salmon migration routes create disease and parasite exchange risks that harm wild salmon welfare and raise conservation concerns about disease spillover.
Disease spillover from aquaculture to wild fish represents a welfare harm that extends far beyond the farmed animals. Wild salmon suffering elevated sea lice burdens experience skin damage, immune suppression, increased predation vulnerability and reduced survival - welfare costs caused by the proximity of intensive farming. This is particularly acute for the endangered Atlantic salmon population - the combination of climate change, fishing pressure and aquaculture disease impacts creates cumulative welfare and conservation pressure. Welfare-conscious aquaculture requires not just managing farmed fish welfare but considering the impact on wild animals in the surrounding ecosystem. Siting farms away from wild salmon migration routes and maintaining rigorous lice management are minimum welfare responsibilities.