An experiment was carried out to determine the optimal photoperiod for indoor farming of juvenile redclaws. Crayfish with an average body weight (ABW) of 0.96 ± 0.66 g were stocked into a recirculating aquaculture system (RAS) at a density of 50 crayfish.m-2. During 15 weeks, the crayfish were exposed to four different photoperiods: hours light/dark (L:D) 24:0, 16:8, 12:12 and 0:24.
In this experiment, the highest growth rates were obtained when redclaws were reared in constant light (L:D 24:0), resulting in the highest total biomass and ABW. Highest survival was obtained in the L:D 24:0 and 0:24 treatments. Redclaws farmed in continuous dark conditions, showed the poorest growth rates.
These results suggest that juvenile and pre-adult redclaws should be farmed under continuous light conditions in order to improve growth performance and survival rate. The effect of photoperiod on adult redclaws will be evaluated in a future experiment.