Body-weight variations in four week old Clarias gariepinus

The variation in size and weight of fry and fingerlings of Clarias gariepinus has been a major factor affecting the success of hatchery production of the species. It encourages cannibalism, thus reducing the overall survival. The disparity in weight and population was assessed to determine the necessity of sorting as a reliable method of controlling size disparity and mortality in hatchery production. Two-week-old fry with average weight of 15mg and length range of 0.8-0.9cm were randomly sampled and stocked at 200 fry/litre in 30 litre circular tanks. The fish were fed for four weeks on 45% crude protein diet, ad libitum. At the end of four weeks, there were three groups; large, medium and small with mean weight of 4.02g, 1.24g and 0.17g, respectively. The cumulative mean weight was 1.8g, population ratio was 1:8:10 for large, medium and small, respectively