Fecundity and Spawning Frequency of Sarotherodon Galilaeus in a Concrete Pond
Fecundity of 26 specimens of Sarotherodon galilaeus cultured in a small concrete pond, 6.3 x 1.4 x 1.6 m, was determined by the “whole-count” method. The fish were not fed artificially but depended on natural piiytoplankton growth, mainly Chlorococcus and Chlorella, for food. Pond water temperatures varied between 26° and 32°C. Fecundity ranged from 69 to 302 (mean = 149) for fish measuring 6.7 to 11.0 cm total length with body weights of 6.2 to 22.3 g and gonad weights of 0.32 to 1.23 g. The relationship between fecundity and total length was non-linear while fecundity—body weight and fecundity—ovary weight relationships were linear. The frequency distribution of ova diameters in mature ovaries showed two separate modes representing mature and immature ova, suggesting that the species has a restricted spawning period in the pond.