The purpose of the present study was to investigate the growth performance of an invasive alien species, Clarias gariepinus from river Yamuna (Delhi segment) in Indian waters by utilizing Length-Weight Relationship (LWR) and Condition Factor (K) with respect to different maturity stages. In females, the value of regression coefficient 'b' was observed to be less than 3 during different reproductive phases i.e. immature stage, not ripe stage, ripe stage, running ripe stage and spent stage. In

more »

... es, the value of 'b' was observed to be less than 3 with maximum in mature males and minimum in immature males. In total, value of 'b' was found to be higher in females (p<0.01) as compared to males. The mean values of condition factor (K) for both sexes were found to be < 1. In addition, individuals of smaller length sizes and in early stages of reproductive cycle of both sexes were found in better condition than larger sized individuals in later maturity stages. Despite of negative allometric growth pattern and not so good health status of river, it has successfully colonized the river because of certain physiological adaptations.