The Effects of Crowding Stress, Different Diets and Different Size Classes on the<i> Growth Rate of</i> Clarias gariepinus

Abstract

Indoor-studies conducted on three growth variables - stocking rate, diets and size classes at fortnightly intervals revealed that out of 460 dterminations of length and weight of Clarias gariepinus (12 cm mean total length and 11 gm mean weight) taken, the results showed that: at constant area, growth rate of Clarias gariepinus reduced by as much as 75% when the density was increased from one to three individuals per square metre - regardless of food supplied. Sinking feed with high carbohydrate content enriched with vegetable protein rather than animal protein is more beneficial to the species. Fish with standard length less than 17 cm grew faster than those with greater lengths. This corresponds to and indeed accentuates the importance of transition pond stage in aquacultural management.The implication of this finding with respect to aquaculture management is discussed herein.



Journal of Aquatic Sciences Volume 16, April 2001, pp. 70-75



KEY WORDS:

Growth rate, crowding stress, negative allometry, Clarias gariepinus.