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ABSTRACT
Nile tilapia Oreochromis niloticus were held at a water salinity of 11.5 ppt, a temperature of 27 ± 0.5°C, pH of 7.6–8.1, 100% of oxygen saturation, and 18:6 (L:D) 2,500 lux light regimen. Fish were fed a 40% protein food. A total of 78% of spawns were by brooders of 21.5–31 cm and 165–495 g. Absolute fecundity varied between 50 and 2,600 (mean 853 ± 25) eggs per clutch. Relative fecundity varied from 0.29 to 6.8 (mean 2.77 ± 0.13) eggs/g of female. Mean of wet weight of egg clutches was 4.98 ± 0.31 g during the study period, increasing with size of female (p < .05). Mean of wet egg weight was 0.0062 ± 0.0001 g. Means of wet weight of tilapia eggs gradually increased during the study period. Diameter of the eggs varied between 1.8 and 3.5 mm, with a mean of 2.58 ± 0.009 mm, increasing with average length and weight of spawners.
Funding
Many thanks to the Iranian Fisheries Research Organization for supporting this research.