Net pen aquaculture for salmon and other species operates in open water environments where welfare management is challenging. Understanding the welfare issues helps consumers and advocates drive improvement.
Net pen aquaculture presents welfare challenges that are partly inherent to the open-water environment. Sudden water quality changes from algal blooms or jellyfish incursions cause acute welfare crises that can result in mass mortality from suffocation - a prolonged and distressing death. High stocking densities increase aggression, fin damage, and stress. Disease outbreaks spread rapidly through the interconnected water column. Treatment procedures - handling fish for lice removal or medication - cause acute stress. The welfare trajectory for net pen aquaculture requires both better monitoring systems to detect problems earlier and investment in higher-welfare production models including RAS and improved net pen designs.