Behaviour and coping of individual salmon in farm environments with fluctuating oxygen and hydrodynamics (Salmon Dynamics)

Farming environments experienced by salmon with modern sea-cages fluctuate depending on hydrodynamic flows. Salmon may sense and respond to a range of fluctuating environmental variables within sea-cages, including light, temperature, salinity, dissolved oxygen, and water currents. In particular, salmon may experience oxygen levels that fluctuate from normoxic to hypoxic over short temporal (minutes) and spatial (metres) scales. A fundamental understanding of how individual salmon behave and cope in farm environments with fluctuating oxygen and how these fluctuations depend on external and internal cage hydrodynamics may enable improvements to farm management, technology and design. Four integrated work packages (WPs) will generate knowledge on fish beha viour and coping mechanisms in dynamic cage environments, the nature of current flows through and around cages, and their intrinsic inter-connections. WP1 will focus on understanding the individual experience and coping mechanisms of salmon in cage enviro nments subject to short-term oxygen variations. WP 2 will assess the behavioural and physiological responses of salmon to acute and chronic short-term fluctuations in oxygen levels. WP 3 will acquire data to validate models that describe water flow inside and through a single cage and within and around a system of cages for optimum oxygen distribution. WP 4 will develop a model which integrates both the swimming behaviours of fish and cage hydrodynamics to predict both optimal production capacities and fi sh farm configurations. We envisage that the results of the project will add value to the Norwegian aquaculture industry through better management of cage environments, which will ensure acceptable fish welfare and improve operational efficiencies. Furthe r, the results may provide novel information to adapt cage designs and configurations to optimize hydrodynamic flows.