Biological aspects of Schilbe intermedius (Ruppell, 1832) in the Nyanza Gulf of Lake Victoria, Kenya

Abstract

Silver butter catfish (Schilbe intermedius) is an indigenous fish species in Lake Victoria. It has a good economic value because of the quality and freshness of its flesh, increasing its demand for consumption. It is potamodromous, with its stock in the lake declining because of overexploitation by the use of illegal fishing gears at the river mouths on their way to spawning areas. Fish samples (321) were obtained from commercial gill net (1.5–3 in.) fishers within Nyanza gulf. The fish samples were weighed (g) and measured (cm), dissected and sex determined by visual inspection of the gonads. Ovaries for mature female fish specimens were preserved for analysis of fecundity. Fecundity was determined by the gravimetric technique. The mean (±SE) length and weight for all fish were 18.2 ± 0.2 cm TL and 51.9 ± 1.9 g, respectively. The female fish (20.0 ± 0.2 cm) were significantly (F = 199.80, p