Growth, survival and food conversion of Atlantic salmon reared at four different densities with common water quality

Our objective was to determine the maximum effective rearing density for Atlantic salmon (Salmo salar) at 17.5°C, a temperature typically used in hatcheries to accelerate growth. We reared 5.8‐g (mean weight) parr for 80 d to final rearing densities of 14–55 kg/m² (rearing unit bottom area) or 80–310 kg/m³ (rearing unit volume). Weight gain was slightly depressed in fish at a final rearing density of 26 kg/m² (146 kg/m³), but mortality, food conversion, and gain in length were not affected. At densities greater than 26 kg/m², fish growth was slower and food conversion was higher, but mortality was unaffected. Atlantic salmon may be reared at 17.5°C to densities of at least 14 kg/m² (80 kg/m³) without adverse effects on growth and health, but final rearing densities should not exceed 26 kg/m².