FCRSOFT
What Should Stocking Density Be?
How is stocking density (kg/m³) set in cages, ponds and RAS? The effect of high density on FCR, growth and mortality, and the right stocking calculation.
Stocking density is the weight of fish per unit volume (kg/m³). The right density uses your facility’s capacity while protecting growth and health.
How is stocking density calculated?
Stocking density (kg/m³) = Biomass (kg) ÷ Volume (m³)
Free tool: Fish Biomass Calculator
Typical ranges
At harvest, 15–25 kg/m³ is common for sea bass and sea bream in sea cages, 20–40 kg/m³ in trout raceways depending on water exchange, and 50 kg/m³ or more in intensive RAS. The right value depends on oxygen, water exchange and species.
Effects of high density
- Oxygen consumption rises and critical drops appear in the early morning.
- Competition and size variation increase, and FCR rises.
- Stress and disease risk increase, and mortality rises.
Plan stocking for density at harvest
When stocking juveniles, aim for the density at harvest, not today’s. Work backwards: harvest biomass from volume, fish count from harvest weight and juveniles from expected survival.