Preventing farmed fish escapes through robust cage design protects both wild fish welfare and ecological integrity; the welfare of escaped farmed fish and the ecological impact on wild populations are both relevant.
Sea cage escape prevention has both welfare and conservation dimensions that are aligned in their interests. Escaped farmed fish face stressful acclimation to wild conditions, predation, and difficulty finding appropriate food sources. Wild fish populations are affected through competitive displacement, disease transmission, and hybridisation that reduces fitness. The welfare case for robust escape prevention is therefore twofold — protecting both the welfare of individual escapees and the ecological welfare of wild populations they affect.