Open-net salmon farming affects wild salmon populations through disease transmission and genetic interbreeding, creating welfare concerns that extend beyond farm boundaries.
Open-net pen salmon farming creates welfare problems that extend beyond the farm to affect wild salmon. Lice-infected wild juvenile salmon face welfare costs — pain, immune suppression, and death — that are directly caused by farm operations. This creates an ethical situation where the welfare costs of salmon farming are partially externalized onto wild fish that have no protection under aquaculture welfare frameworks. Closed containment systems resolve this by eliminating the physical connection between farm and wild environment. Supporting consumer campaigns demanding closure of open-net pen operations advances welfare for both farmed and wild fish.