Comparative analyses of growth parameters of pure Clarias gariepinus and its hybrid in monosex culture

Abstract

This study compared sexual differences in growth parameters of pure and hybrid African catfishes (Clarias gariepinus and Clariabranchus) raised in a monosex culture. The two species were obtained from 281 fishes comprising 150 pure breed and 131 hybrids in an earlier study and grouped by sex separately as male and female in four separate plastic tanks, representing two replicates per sex. Ten each of the pure clarias and its hybrid were reared in each tank. In all, 40 male and 40 female fish comprising 20 each of the pure clarias and its hybrid for each sex were evaluated for the growth parameters. A total of 80 fish were included in this study and the study lasted nine (9) weeks. The fish were fed commercially compounded feed twice daily throughout the period of the experiment. Length-weight relationship and growth parameters such as Mean Growth Rate (MGR), Specific Growth Rate (SGR), Absolute Growth Rate (AGR), Relative Growth Rate (RGR), Condition Factor (CF) were computed and evaluated for sex effect. All statistical analyses involving descriptive, general linear model analysis of variance (ANOVA) and post hoc test were done using Minitab® 17 Statistical Software. Sex had significant (P<0.05) effects on all growth parameters except Absolute Growth Rate (AGR) albeit at different levels, but specie only had significant (P<0.05) effect on Mean Growth Rate (MGR), while the interaction of sex x specie exerted significant (P<0.05) effects on all growth parameters except Condition Factor (CF). This study revealed that growth performance is significantly (P<0.05) affected by sexual dimorphism and also by interaction of sex and specie.