The present experiment was carried out at the hatchery of Arab Fisheries Company at Abbassa village, Abu-hammad district, Sharkia Governorate, Egypt. The experiment aimed to study the effect of the year of hatching, male body weights and female body weights on reproductive traits of Nile tilapia fish (Oreochromis niloticus). The experimental period extended from 1April 2002 and lasted 29th of May 2003. Six concrete ponds (3 × 10 × 1m) were used and represented six treatments and each pond was stocked with 50 females and 17 male. Females were divided according to their body weights to three groups, 300, 400 and 500 g and males also were divided into two groups 300 and 400 g. The obtained results could be summarized as follows:
Total egg weight (g) per female (EW/F) and egg weight (g)/gm of body weight (EW/GF) did not significantly affected by the year of hatching or by the weight of male of Nile tilapia. EW/F increased gradually as female body weight increased. EW/F for the three groups 300, 400 and 500 g were 12.33, 14.64 and 21.91g, respectively and the differences were not significant and the same trend was also observed for the effect of female body weight on EW/GF.
Averages of absolute fecundity as affected by the year were 1215.39 and 1411.71 for the two years 2002 and 2003, respectively and the differences between means were significant (p |
