Abstract
The effects of three broodfemales selection methods: i) Broodfemales selection by size at maturity as small and large, ii) Broodfemales selection by age at maturity as early and late maturing and iii) Broodfemales selection by 90 d post-maturity spawning performance were evaluated on Nile tilapia, O. niloticus reared in a hapa-in-pond system over 12 month experimental period. The method broodfemales selection by size at maturity didn’t improve total seed production while broodfemales selection by age as early and late maturing groups failed to effectively separate the broodfemales into productive and unproductive groups. On the other hand, the method brood females selection by 90 d post-maturity spawning performance resulted in similar age at first spawning (d), initial and final body weight (g), eggs spawn-1, eggs kg female -1 d-1 and ISI (d) group to the method broodfemales selection by age at first spawning as early and late maturing. However, it had advantages in effectively separating the broodfemales into productive and unproductive groups and also in increased eggs female-1 d-1 and spawn female-1 y-1. Therefore, selecting broodfemales by 90 d post-maturity spawning performance allowed improved synchronization of broodfemeles through maintaining 83 ± 2.02% active broodfemales in the population, higher by 42, 20 and 50% than the methods broodfemales selection by size, by age at first spawning and the control, respectively.
Keyword: Nile tilapia, Oreochromis niloticus, seed production, selection method, maturation, spawning activity