Influence of African catfish (Clarias gariepinus) brood stock size on fingerlings growth rate.

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This work was undertaken to investigate the effects of brood stock size on growth performance of C. gariepinus. In a 4×3 factorial design, four different brood stock sizes (0.7, 0.8, 1 and 1.75 kg - ♂ ) were crossed with three different sizes of female brood stock (0.8, 1, and 1.75 kg (♀) and 6 experimental treatments. Brood-fish were bred at a sex ratio of one female to one male (1♀:1♂). The experimental treatments were assigned according the factorial design with two replicates per treatment giving total number of 12 spawning tanks. C. gariepinus brood stock size significantly (P≤0.05) affected the natural sizes of fingerlings. Considering brood stock size, the larger brood fish had the highest jumpers (167- 21.30%) and second to the last in the number of runts (367 – 46.81%) when compared with other treatments. Treatment 5 had the highest number of medium sized fingerlings while treatment 2 had the highest number of runts and least number of jumpers. Treatment 1 had the least number of medium sized fish while treatment 4 had the least number of runts. The best growth performance in terms of the number of jumpers was found in treatment 6 spawned by larger brood fish. It is recommended to use larger brood fish during the propagation season in hatcheries if more jumpers are major targets of production.