Effect of rest systems during spawning season on the spawning efficiency of Nile tilapia in commercial hatcheries [electronic resource].

Includes references.

This experiment was conducted to compare the effect of two resting system for 15 days of broodstock (rest in hapas and rest in ponds) versus no-resting control treatment on 6 months larvae production and spawning synchrony of Nile tilapia Oreochromis niloticus stocked in 12 hapa with a water volume of 25 m3/hapa suspended in earthen pond, four hapa/treatment. Adult males and females with mean body weights of 140 g and 125.4 g, were stocked at a rate of 120 fish/hapa with a male to female sex ratio of 1:3. Water temperature at 29 ± 1.0 oc and salinity 2.4 ppt were maintained throughout the experiment. The results showed that broodstock in the rest system had higher seed production and spawning synchrony compared with those in no rest. The resting system resulted in an increase from 20.6 to 31. 7% in larvae/female. The different spawning parameters of broodstock in the rest in hapa and rest in pond were higher than in the no rest (control). Results suggested that broodstock resting strategy had a long-term improvement effect on larvae production and spawning synchrony, and resting all breeders in ponds was more profitable but faced a problem, its needed two pond more than hatchery pond which is not available in most hatcheries.

Summary in Arabic.

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