EFFECTS OF AGE AND STOCKING DENSITY ON SPAWNING PERFORMANCE OF NILE TILPIA, OREOCHROMIS NILOTICUS (L.) BROODSTOCK REARED IN HAPAS

This experiment was undertaken to investigate the effects of age and stoking density on spawning performance and growth rates of Nile tilapia Oreochromis niloticus (L.) broodstock reared in hapas. In a 2×3 factorial design, two different broodstock ages (1-year old and 3-years old) were combined with three different broodstock densities (4, 8 and 12 fish / m2 for lower, intermediate and higher broodstock stocking density, respectively) to obtain 6 experimental treatments. Brood-fish were stocked at a sex ratio of three females to one male (3 :1). Nile tilapia broodstock age and stocking density significantly (P≤0.05) affected the natural spawning performance. Regardless of broodstock age, the lower stocking density had the highest seed / female (12١3 ± 184.14 seeds), seed / g female (6.93 ± 1.28 seeds) and seed / day (10.99± 1.53 seeds) followed by intermediate density (1036.25 ± 129.3