EFFECT OF DIFFERENT STOCKING DENSITIES AND SEX RATIO ON REPRODUCTIVE PERFORMANCE OF NILE TILAPIA (Oreochromis niloticus) IN CONCRETE PONDS

Ahmed A.A. Ali

Fish Physiology and hatchery Department, Central Laboratory for Aquaculture Research, Agriculture Research Center, Ministry of Agriculture,
Egypt.

Abstract

These experiments was conducted to investigate the effects of broodstock stocking density, sex ratio and there interaction on reproductive performance of Nile tilapia (Oreochromis niloticus) broodstock. Three trials was design, the first, two different broodstock density (2 fish/m3 and 3 fish/m3) at six ratio of 1♂:2♀, the second trail three different broodstock sex ratio (1♂:1♀, 1♂:2♀ and 1♂:3♀) at 2 fish/m stocking density and the third interaction between them. The experimental trials were assigned according the one way analysis of variance design with two replicates per treatment giving total number of 22 concrete ponds and contained for two months. The results of broodstock density at 2 fish/m3 had the highest fry production /female. The results obtained with sex ratio 1♂: 1♀ was significantly higher than other sex ratio/female. The results of interaction between stocking density and sex ratio cleared that significant effect obtained and the highest fry production /female obtained with density 2 fish/m3 with sex ratio 1♂:1♀ and the lowest fry production obtained with density 3 fish /m3 and 1♂:3♀ sex ratio. But total fry production for pond was more efficient with sex ratio 1♂:3♀ and density 3 fish/m3 was suitable for commercial hatcheries.

Key words: Nile tilapia, broodstock, sex ratio, stocking density, reproductive and hatcheries.