Effect of Water Temperature on Masculinization and Growth of Nile Tilapia Fish

Abstract

The main aim of this work is to study the effect of water temperature on masculinization, growth and survival of Nile tilapia. To achieve that two experiments were carried out to study the effect of water temperatures (25°C, 30°C and 35°C) and periods of time (1, 2, 3 and 4 weeks) on the male ratio, mortality rate and weight of Nile tilapia fry in the first experiment. While the second experiment aimed to evaluate the growth and survival rate of sex reversed tilapia fry which obtained from the first experiment. The obtained results indicated that the male ratio and mortality rate increased with increasing the water temperature and period of time rearing. The highest value of male ratio and mortality rate (91.50% and 17.13%) was obtained at 35°C water temperature and four weeks of rearing. The weight of Nile tilapia fry significantly increased from 0.16 to 1.51 g, 0.30 to 2.67 g and 0.27 to 2.05 g at 25°C, 30°C and 35°C, respectively after 1, 2, 3 and 4 weeks of rearing. The Nile tilapia fry previously treated by water temperature and period of time rearing increased each of body weight, weight gain and specific growth rate, while the feed conversion ratio decreased with increasing the water temperature and period of time rearing.