Effect of different light regimes on indicators of incubation of Persian sturgeon (Acipenser persicus) eggs

The effects of five different light regimes on development, survival rate, hatching time and rate of Persian sturgeon (Acipenser persicus) embryos were investigated. Fertilized eggs were exposed to five different light regimes (24L:00D, 12L:12D, 16L:08D, 08L:16L and 00L:24D) until hatching time. Significant differences were observed in blastulation, gastrulation, neurulation stages among treatments. The fungal infection rate was significantly the highest (14.1 ± 1.2) in 12L:12D and the lowest (2.4 ± 0.2) in constant darkness. The highest mortality rate (38.4 ± 1.4) was observed in 12L: 12D, while the lowest (10.9 ± 0.9) was in 16L:08D. Hatching rate was significantly higher in 16L:08D (88.8 ± 3.9) than those in other treatments. Embryos incubated under 12L:12D and 08L:16L hatched earlier (7 days after fertilization), while mass hatching in 16L:08D treatment was observed 9 days after fertilization. Embryos incubated under continuous darkness produced smaller larvae in length, body and yolk sac area. In general, considering the lowest mortality and highest hatching rate of embryos incubated under 16L:08D and absolute darkness, it is suggested that these light regimes are suitable for incubation of Persian sturgeon embryos in terms of mass hatching time, energy access and larval quality.