Effects of fish density on growth and smoltification in intensive production of Atlantic salmon ( Salmo salar L.)

Parr of Atlantic salmon ( Salmo salar) were reared at four different densities (21, 43, 65 and 86 kg fish m − 3 ) for 100 days in fresh water under conditions where equal specific flow rate was maintained in all density groups (0.3 L kg fish min − 1 ). Water quality parameters such as oxygen level, pH and CO 2 were monitored and kept within recommended values. When ready smolted the fish were transferred to seawater for a further 15 weeks. The findings suggest no negative effects on Atlantic salmon when reared at densities up to 86 kg m − 3 as long as water flow rate, water quality parameters and food rations are within the recommended standards. Maintaining sufficient food supply is important at high densities to avoid negative social interactions.