Effects of stocking density and photoperiod manipulation in relation to estradiol profile to enhance spawning activity in female Nile tilapia

This study investigated the effects of stocking density and photoperiod manipulation in relation to plasma estradiol-17? (E2) profile to enhance spawning activity in female Nile tilapia (Oreochromis niloticus) using F1 clonal crosses. The fish were divided into experimental and control groups and subjected to a combination of stocking density and photoperiod treatments (40kg/m3;6L:18D, 40kg/m3;12L:12D and transferred into single compartments at 12L:12D; 14kg/m3;12L:12D), respectively. Blood samples were taken by caudal puncture from experimental fish for estradiol profile analysis. Results showed that experimental fish exhibited significantly higher number of spawns per day, total fecundity and relative fecundity (p