Feeding and nutrition of pre-harvest Atlantic salmon in seawater RAS at four temperatures

As water temperature increased (Phase 1) feed intake was higher at elevated temperatures (>19°C) whereas there were no differences in growth or FCR. ΔCV weight showed the individual growth trajectories were closer at 21°C.

Pre-selected individuals showed wide variation in performance (Phase 2), individuals with condition factor of >1.2 were compared at 15 and 21°C. After more than 46 days at an elevated temperature (>19°C) there were few significant differences across growth, condition or muscle lipid. This indicated a level of robustness in a sub-group of salmon.

However, the performance of these more robust salmon was declining.

Large Tasmanian Atlantic salmon held at elevated temperatures (with 100% DO) in RAS declined in performance but continued to feed and grow for at least 7 weeks. Pigmentation appeared the most sensitive parameter measured.