Wild Atlantic and Pacific salmon spend years in the open ocean before returning to rivers to spawn. Their welfare during this oceanic phase is shaped by food availability, predation, disease, and ocean warming.
The ocean phase of wild salmon life has received less welfare attention than freshwater or farm stages, yet it involves sustained physiological challenges. Chronic food shortage causes measurable stress and depletes the energy reserves salmon need to survive spawning migration. Ocean warming disrupts thermal comfort zones, pushing fish into suboptimal habitats. Sea lice infestations cause immune activation and altered behaviour in wild juveniles. High-seas bycatch results in injury and death for millions of fish annually. Addressing wild salmon welfare requires tackling both direct threats like bycatch and systemic drivers like climate change and aquaculture disease vectors.