The practical work of the present experiments carried out at the World Fish Center, Abbassa, Abou Hammad, Sharkia, Egypt. The experiment was aimed to investigate the effect of spawning month (April and May) dietary protein level (25 or 35%) and protection of spawning tanks (covering or uncovering of the spawning tanks) on fry production and average fry weight of Nile tilapia. The obtained results can be summarized as follow:
- Fry production/tank were found to be 6462 and 19082/tank during the two months April and May, 10719 and 14824/tank for the two dietary protein levels, 25 and 35% and 16428 and 9115 fry/tank for the covered and uncovered tanks, respectively and the differences in fry production due to the effect of spawning month, dietary protein content and tank protection were significant.
- Averages of individual fry weight as affected by month, dietary protein content and protection were found to be 0.025 and 0.016 g during the two months April and May, 0.021 and 0.019 g for the two dietary protein levels, 25 and 35% and 0.018 and 0.023 g for the covered and uncovered tanks, respectively. Spawning month and tank protection significantly affected individual fry weight while dietary protein content had no significant effect on fry weight.
- The interaction between the studied factors affecting individual fry weight of Nile tilapia indicated that the highest average individual fry weight was recorded for fish group raised in covered tanks and received the lower protein content during April. On the other hand, the lowest average individual fry weight was recorded for broodfish raised in an uncovered tanks and received the higher protein level (35%) in May.
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