THE EFFECTS OF DISSOLVED GAS SUPERSATURATION ON HATCHABILITY AND MORTALITY OF ACIPENSER DABRYANUS DUMERIL

The fertilized eggs, larvae and juveniles of Acipenser dabryanus Dumeril were exposed to different Total Dissolved Gas (TDG) supersaturation water to study the hatchability of fertilized eggs and the mortality of fry and juvenile. The results showed that TDG supersaturation impacted hatchability. The hatchability of control group and TDG levels of 110%, 120%, 130%, and 140% were (79±3)%, (84±0)%, (92±2)%, (91±1)% and (78±2)%, respectively. There was no significant difference between the 140% group and the control group (P>0.05), and the hatchability of 110%, 120% and 130% groups were higher than that of the control (P<0.05). Larvae at 1—2 days were exposed to different levels of TDG for 96 hours, and there was no death phenomenon in control group. The mortality of 110%, 120%, 130%, and 140% were (3.45±0.12)%, (3.45±0.00)%, (5.59±1.86)% and (1.15±1.99)%, respectively. It was less than 7%. The 130% group was significantly higher than that of the 140% group (P<0.05), while there was no significant difference between other groups (P>0.05). Juveniles at 50 days were exposed to TDG supersaturation for 96 hours, and there was no death phenomenon in control group. The mortality increased with enhanced TDG supersaturation (P<0.05). The mortality rate in each group was above 50% with 100% for the 140% group. There was no significant difference between 110% group and 120% group, and other groups had significant difference. The half-lethal time (LT₅₀) were significant differences among groups. TDG saturation was negatively associated with LT₅₀. In general, TDG levels of 110%, 120%, 130% significantly promoted the hatchability of fertilized eggs, while the 140% had no impact on the hatchability. TDG levels of 110%, 120%, 130%, and 140% could lead to the death of larvae and juveniles of Acipenser dabryanus Dumeril, but the effect on larvae was slight, and there was no significant correlation between mortality and TDG saturation. While the effect on juveniles was serious, the influence degree increased with enhanced TDG saturation.