Fecundity and spawning frequency of Sarotherodon galilaeus in a concrete pond

Abstract

Fecundity of 26 specimens of Sarotherodon galilaeus cultured in a small concrete pond, 6.3 × 1.4 × 1.6 m, was determined by the “whole-count” method. The fish were not fed artificially but depended on natural phytoplankton 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.