Aquaculture Net Pen Welfare and Escapes

Open-net pen aquaculture raises significant welfare and environmental concerns, including crowding, disease, escapes of farmed fish into wild ecosystems, and sea lice spread.

Key Facts

Global aquaculture now produces more fish than wild capture fisheries for human consumption
Net pen fish experience crowding, water quality variation, and disease pressure
Escapees from fish farms interbreed with wild populations, potentially reducing genetic fitness
Sea lice from net pens spread to wild salmon smolts passing through farm areas
Closed containment systems eliminate most net pen problems but require major capital investment

Welfare Considerations

Open net pen aquaculture concentrates large numbers of fish in variable conditions, creating chronic welfare challenges from crowding, poor water quality, parasites, and disease. Fish welfare in net pens depends heavily on stocking density management, health monitoring, and prompt disease treatment. The externalities — sea lice spread to wild fish, escape and genetic introgression — create welfare harms extending beyond the farmed population. Closed containment systems address most of these issues at higher cost.

What You Can Do

Choose salmon certified under standards with welfare and environmental auditing
Support investment in closed containment aquaculture as a long-term solution
Advocate for net pen siting regulations that protect wild salmon migration corridors
Ask retailers about net pen welfare standards in their salmon supply chains
Support research into economically viable alternatives to open net pen salmon farming