Cannibalism of Juvenile Catfish (Clarias Gariepinus Burchell)

Abstract

The study was conducted to examine the phenomenon of cannibalism among juveniles of the African catfish (Clarias gariepinus Burchell) of the same year class. At the start of the 21 day experiment, each catfish fingerling weighed approximately 4.1g. The fingerlings were stocked in a plastic tank at a stocking density of 100 fingerlings in the tank. There was unequal weight gain among all the fingerlings in the tanks, resulting in the significant difference of two fingerlings weighing 27.2g and 42.4g respectively. These two fingerlings accounted for over 68% mortality of the original stock. The two large fingerlings were isolated in two tanks of 0.23m 3 size and fingerlings weighing approximately 7.6g were introduced daily starting with two and increased in a geometric progression of four and eight for 13 days. In combination the catfishes A and B consumed a total of 42% of the juveniles in 9 days. In separate chambers Catfishes A consumed a total of 11 juveniles in 13 days accounting for 10.6% of entire number of juveniles introduced. Partial cannibalism which consisted of juveniles killed but not swallowed wholly was higher accounting for 19.2% of the total introduced. This is in contrast to Catfish B which consumed a total of 52 juveniles accounting for 50% of number introduced with only a 1.9% partial cannibalism. This accounts for the significant differences in the weight values with Catfish A gaining a total of 8.5g in contrast to 184.5g gained by Catfish B. It is evident from the study that cannibalism among juvenile catfishes within the same year class can be identified and with proper management of size variationimprove the survival rate of the population of each year class.