Each RAS contained an experimental fish group originating from the same spawning of broodstocks kept in captivity at UCN. Both groups were acclimatized for two months before beginning data
collection. Palm fish juveniles weighing between 300 g and 500 g were reared at a density of 24 kg/m3 in each 1 m3 circular tank and fed a commercial diet at 1% of biomass per day (Table 1).
The experiments were carried out between September and November 2009 in Coquimbo, Chile (29◦57
S–71◦21W) without the use of artificial light. The experiments were conducted under
outdoors tanks subjected to natural photoperiod and farm-like rearing operational conditions for both systems. The experimental conditions are shown in Table 2