Effects of different light intensities and photoperiods on growth, survival rate and yolk-sac volume changes of the Persian sturgeon (Acipenser persius) larvae

The aim of this study was to assess the effect of different light intensities and photoperiods on growth, survival, and the yolk sac absorb of the Persian sturgeon, Acipenser persicus, larvae. Larvae were reared from hatching to yolk sac absorb (eight days) at four light intensities (0, 50, 150 and 300 lux) and three photoperiods (00L:24D, 12L:12D and 24L:00D) which consisted of seven treatments and a control group. Growth factors, including the length, weight, weight gain, specific growth rate condition factor, the percentage of body weight gain and survival rate were calculated in the larvae. The larvae showed significant growth and better yolk sac absorption at the high light intensity (300 lx) and 24L:00D photoperiod compared to the low light intensity (0 lux), continuous darkness photoperiod, and the control group. There were significantly higher survival rates for larval Persian sturgeon in the 50 lx and 12 h photoperiod and 0 lux and 24 h photoperiod (73.1±0.04 & 72.41±0.12% respectively) were compared to larvae reared in the 300 lux light intensity and 24 h photoperiod (47.06%) treatment until 8dph. There was no significant difference observed in the condition factor among different treatments. This study revealed that photoperiod and light intensity were important factors on growth - parameters, survival rate and yolk-sac absorption of the Persian sturgeon in the larval stage.