LAUSR

Abstract The heritability and genetic correlations for reproductive traits were estimated for North African catfish, Clarias gariepinus (Burchell, 1822) (Cg). Data were collected from 349 females at 486 days old, and 273 males at 510 days old, representing 82 full-sibs and 27–28 half-sibs, respectively. The studied traits included gonadosomatic index (GSI) of males and females, relative fecundity (number of eggs/kg-female) (RF), average egg weight (AEW), sperm concentration (SC) and percentage live sperm (LS). The heritability was low for all traits (0.0457 ± 0.0035 for female GSI, 0.0199 ± 0.0015 for RF, 0.0443 ± 0.0034 for AEW; and 0.0276 ± 0.0022 for male GSI, 0.0224 ± 0.0019 for SC, and 0 for LS). Most of genetic correlation was low among the reproductive traits (−0.18 to 0.33, irrespective of sign) except for moderate to high genetic correlation for female GSI&AEW, RF&AEW and male SC&LS. The genetic correlation values between body weight at spawning and reproductive traits were low (−0.03–0.06). The present results imply that selection to improve reproductive traits of Cg may be infeasible, and that selection to improve growth will not have detrimental effects on reproductive traits of males or females.