Responses to crowding stress in Atlantic salmon reared in different aquaculture systems

Recirculation systems (RAS), which reduce water consumption and improve pathogen control are increasingly used in Atlantic salmon aquaculture. Performance and adaptation of fish to new farming environment is actively investigated. Here, responses to crowding stress were compared in salmon reared in two systems (RAS with brackish water and flowthrough with full salinity water) at low and high density. Salmon reared in RAS and flowthrough systems at low and high densities (20-40 kg/m3 and (80-115 kg/m3) was exposed to crowding stress (300 kg/m3 for 30 min). Skin was sampled before (control) and 24 h after challenge.