Effects of CO2 and temperature on embryonic development of stripped catfish(Pangasianodon hypophthalmus)

Abstract

This study was conducted to determine the effect of temperature and carbon dioxide on embryonic development of striped catfish (Pangasianodon hypophthalmus) in order to understand the adaptation of the fish to CO2 and temperature.The experiment on the single and combined effects of temperature and CO2 on the embryonic development of striped catfish in the time from fertilization to hatching were arranged with three experiments (i) Experiment 1 was set up with 4 treatments including: three levels of CO2 (1, 2 and 3%) and control (non- aeration), each treatment had 3 replicates and completely randomized design; (ii) Experiment 2 consisted of five temperature levels (27; 30; 33; 36 and 39°C) and control (at room temperature); (iii) Experiment 3 consisted of selected CO2 concentration (1 and 2%) and two temperature levels (27 and 33°C); and control (room temperature and no aeration). The results showed that at the CO2 concentration from 1 to 3% in the water environment badly affected to the embryonic developmental time, it ranged average from 21.2 to 24.4 hours and reduced hatching rate. The treatment of CO2 3% level was the slowest development (24.4 hours), the hatching rate was 47.7%; and statistically significant difference compared to other treatments (p<0.05). Temperatures higher than 36°C effected to the embryonic development, embryos unable to grow to the hatching stage. At a temperature range of 27 to 33°C, the embryonic development was proportional to temperature so that the longest embryonic development at 27°C was 22.5 hrs; but the lowest at 33°C was 20.2 hrs. But there was not statistically significant difference between control and treatment of 30°C (p <0.05). Striped catfish in the embryonic stage can survive in water containing CO2 from 1-3%, temperature from 27 to 33°C.