Impact of sex ratio and stocking density on the induced spawning of the Egyptian sole (Solea aegyptiaca Chabanaud, 1927)

This study was conducted to evaluate the impact of sex ratio and stocking density on the induced spawning and reproductive performance of the Egyptian sole (Solea aegyptiaca) broodstock. Broodstock spawners were intermuscularly injected with Human Chorionic Gonadotropin Hormone (HCG) below the dorsal fine base; the dose was 7000 IU/Kg body weight of fish. In this study, three different broodstock sex ratios: 1:1, 1:2 and 2:1 (male ♂: female ♀) were tested. The highest fertilized eggs/ treatment and larvae/ treatment were observed in sex ratio (1♂:2♀). While, the highest fertilized eggs/ female, fertilized eggs/ g female, hatching rate and number of spawning were observed in sex ratio (2♂:1♀). Under the conditions tested in this study, larvae production of S. aegyptiaca was affected by different broodstock sex ratios and improved at a sex ratio (1♂:2♀). Also, four different broodstock stocking densities: 0.5, 0.75, 1, 1.25 Kg/m³ were tested. The highest fertilized eggs/ treatment, fertilized eggs/ g female and larvae/ treatment were observed in stocking density 0.75 Kg/m³ followed the other stocking densities. The lowest fertilized eggs/ female and/ g female were observed in stocking density 1.25 Kg/m³. Under the conditions tested in this study, larvae production of S. aegyptiaca was affected by different broodstock stocking densities and the best stocking density was 0.75 Kg/m³. Also, results demonstrated superiority of artificial spawning compared to natural one. From the results of this study, it is recommended to use artificial spawning in S. aegyptiaca with sex ratio (1♂:2♀) and stocking density (0.75 Kg/m³).