Samantekt:
In order to study the possible interactive effects of salinity and photoperiod on growth, feed conversion, and blood chemistry in juvenile halibut, 2,604 (initial mean weight 26.8 g ± 0.2 SEM) juvenile halibut were exposed to six different combinations of salinities (13, 21, or 27‰) and photoperiods [continuous light, C and simulated natural photoperiod (65°N), SNP] for 129 days. Improved (10–20%) growth and 10–24% higher feed conversion efficiency were observed at low and intermediate salinities compared to the high salinity groups. Improved feed conversion efficiency (20%) and temporary growth enhancing effects (10%) of continuous light were observed, but effects faded out as day length in the simulated natural photoperiod group increased. No interactive effects of photoperiod and salinity on growth feed conversion or measured blood chemistry variables (blood sodium, pH level, haematocrit, bicarbonate content, and total carbon dioxide). It is suggested that juvenile Atlantic halibut should be reared at low and intermediate salinities and at continuous light, as this will improve growth and increase feed conversion efficiency.