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Effect of different broodstock densities on the reproductive performance of Nile tilapia, Oreochromis niloticus (L.), in a recycling system
Author(s) -
Ridha M. T.,
Cruz E. M.
Publication year - 1999
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1046/j.1365-2109.1999.00311.x
Subject(s) - broodstock , biology , nile tilapia , oreochromis , stocking , zoology , hatchery , fishery , fish farming , aquaculture , fish <actinopterygii>
The present study was conducted to evaluate the effect of different stocking densities on the seed production of Nile tilapia, Oreochromis niloticus (L.), under intensive recycling hatchery system conditions. Males and females with mean body weights of 163.2 and 105.0 g, respectively, were stocked at three broodstock densities (4, 8 and 12 fish m –2 ) at a male:female ratio of 1:3 in 1 × 1 × 0.43 m (W × L × H) fibreglass tanks. The tanks were illuminated at 2500 lux for 18 h day –1 and the water temperature was maintained at 29 ± 1 °C. Effluent from spawning tanks was recycled through a biological filter with 10–15% replacement of new water per day. The experiment lasted for 126 days. The results showed that breeders stocked at 4 fish m –2 had significantly higher ( P < 0.05) mean values for total seed production, seed kg –1 female day –1 , seed female –1 day –1 , seed m –2 day –1 and spawning synchrony than at 8 and 12 fish m –2 broodstock densities. The mean percentage of seeds in the yolk‐sac and swim‐up fry stages was highest at 4 fish m –2 broodstock density. However, the recovery rate was not affected by broodstock density. It is recommended that further research should be conducted to determine whether weight m –2 , number m –2 or age of broodstock should be the basis for stocking broodstock.