Effect of water depth on growth performance and survival rate of mixed sex nile tilapia fingerlings and adults

الملخص EN

Nile tilapia (O.niloticus) fingerlings and adult averaging (18 and 100 g in weight) respectively, were reared under 3 different depths (75, 125 and 175 cm) for 90 days to study the effect of water depth on the growth and the survival of overwintered fishes using twelve standing cages.

Fish were fed on a commercial diet containing 26.58 % protein.

The dissolved oxygen, temperature, pH, UIA-N and transparency of water and mortality were recorded for each cage every 15 days during the experimental period.

Also, at the end of the experimental period, the fish were harvested, counted and the growth measurements (weight and total length) were determined.

The statistical analyses indicated that there were significant differences (≤ 0.05) in all parameters between all depths.

Results showed that the final average total length, weight gain, condition factor and survival rate being the best at depth of 175 cm in both two sizes of tilapia during the cold season in Egypt.