Combined Effects of Water Temperature and Salinity on Growth and Feed Utilization of Juvenile Red Tilapia (Oreochromis niloticus X O. aureus)

2 Abstract: There is growing evidence that the climatic change has greatly altered environmental conditions in many aquatic ecosystems over the last decades. Among the ecological factors, temperature and salinity are specific to the aquatic environment. Temperature and salinity are dominant environmental factors affecting marine finfish larvae and can have a significant impact on development, growth rate and survival of marine finfish embryos and larval stages. Two hundred and forty fish of red tilapia (Oreochromis niloticus X O. aureus) fingerlings were used in this study averaging 12.26±0.18 g in weight, 10 fish/tank in duplicates for a period of 56 days in three levels of temperature which were 24, 28 and 32°C combined with four levels of salinities 37, 42, 47 and 52 ppt. There were significant differences in both growth and feed intake among all treatments. The best value of body gain in weight was recorded for 24°C with salinity of 52 ppt treatment which was 7.6±0.05 g and 28°C with salinity of 52 ppt treatment was 6.20±0.21 g and 32°C with salinity of 52 ppt treatment was 6±0.06 g. The survival was 90% for the treatments 28°C with salinity of 42 ppt and 28°C with a salinity of 52 ppt and 32°C with salinity of 47 ppt. From the obtained results, it can be recommend that red tilapia fish can reared at high salinities up to 52 ppt with retention at temperatures between 24 and 28°C. This is encouraged to do cultivation of these fish in lakes with high salinity.