Closed Containment Aquaculture and Fish Welfare

How land-based closed containment aquaculture systems improve welfare outcomes for farmed fish compared to open net pen systems.

Key Facts

Closed containment systems recirculate water through filtration rather than discharging to open water bodies
Land-based recirculating aquaculture systems (RAS) can control temperature, oxygen, pH, and water quality precisely
Fish in optimally managed RAS systems show lower cortisol levels and fewer disease outbreaks than net pen fish
Sea lice, a major welfare problem in open net pen salmon farming, cannot infect fish in closed containment
Mortality rates in well-managed RAS facilities are typically lower than in open net pen systems
The higher capital cost of RAS compared to net pens is offset by year-round production and premium pricing
Several major salmon producers are investing in large-scale RAS facilities in Norway, Canada, and the USA

Welfare Considerations

Open net pen aquaculture exposes fish to a range of welfare challenges including sea lice infestation, crowding stress, net fouling, temperature fluctuation, and predator attack. Closed containment systems address many of these simultaneously by providing a controlled environment where key welfare parameters can be monitored and managed. The adoption of large-scale RAS represents a genuine improvement in fish welfare capacity, though the systems must be properly managed to deliver their welfare potential. Consumer and regulatory pressure for higher-welfare aquaculture is one driver accelerating the transition toward closed containment production.

What You Can Do

Choose aquaculture products from producers that use closed containment or land-based RAS systems
Support certification bodies that recognize and reward closed containment as a welfare improvement
Advocate for aquaculture regulations that require environmental enrichment and welfare monitoring
Ask supermarkets about their sourcing policies for farmed salmon and other aquaculture species
Support research into fish welfare indicators that can be used to audit closed containment facilities