Abstract

• Experiments were conducted to assess the effect of temperatures on hatching and survival rates of Nile tilapia, (Oreochromis niloticus). The present study was carried out at the Laboratory of Aquatic Bioscience Laboratory, Department of Zoology, University of Yangon from June 2017 to March 2018. The fertilized eggs were collected from the mouth of brood stock female tilapia and incubated at three different temperature treatments; 28ºC, 30ºC and 32ºC, each experiment was carried out with duplicate. For control, (ambient temperature, 26ºC) was used to compare with other temperature effects. The present results show that the longest incubation period was 39:02 hours at 26ºC and the shortest 21:51 hours at 30ºC. Incubation period decreased with increasing in incubation temperature. The optimum percentage of hatching rate was 75% at 30ºC, followed by 72% at 32ºC, 68.50% at 28ºC and 70.25% at 26ºC.Similarly, the survival rates were 98% at 26ºC, 97.2%at 28ºC and 97% at 30ºC and 32ºC respectively. The survival rates of fry decreased with the increasing of water temperature. The highest body weight fry (fish) was (4.6 ± 0.28) g at 32ºC and (3.03 ± 0.53) g at 26ºC (ambient) during the study period. Results of the present study showed that water temperature had significant (P<0.000) effect on hatching period. The temperature also has shown that it was significant (P<0.03) effect on growth. According to the present study, most suitable temperature for hatching the egg was 30ºC, while survivals rate was better at 26ºC. On the other hand, high body weight was recorded in fry maintained at 32ºC. The results of the present study found that temperature played an important role on the hatching and survival rates of Nile tilapia.