Atlantic Salmon Welfare: Optimal Stocking Density in Sea Cages

Stocking density in salmon sea cages is one of the most significant determinants of welfare, with evidence guiding welfare-optimal density limits.

Key Facts

Norwegian regulations permit up to 25 kg per cubic metre maximum density
Welfare research suggests optimal density may be considerably lower than regulatory maxima
Fish welfare at density is influenced by access to feed, oxygen distribution, and social stress
Density effects interact with other stressors including temperature and oxygen levels
Commercial pressure consistently pushes toward maximum permitted densities

Welfare Considerations

High stocking density in salmon sea cages causes chronic welfare impairment through increased competition, reduced access to feed for subordinate fish, compromised oxygen distribution in deep areas of the cage, and elevated disease transmission. Welfare-optimal densities are likely substantially below regulatory maxima. However, reducing density directly reduces revenue per cage volume. Welfare-conscious salmon farming accepts some density reduction as a welfare investment. Certification schemes specifying maximum welfare-based densities below regulatory limits represent the key policy mechanism for translating welfare research into practice.

What You Can Do

Support salmon welfare certification schemes specifying density below regulatory maxima
Advocate for evidence-based density limits in salmon welfare regulations
Back research establishing welfare-optimal density ranges for Atlantic salmon
Choose salmon from farms demonstrating commitment to welfare-based density management
Encourage major retailers to set minimum welfare requirements including density standards