Dr. Isaiah Oladipo Opadokun
State to improve on the survival rate and growth performance of C. gariepinus from fry to juvenile stage. The trials were set up in six farms across the State. Two hatching troughs served as Treatment 1 (T1) and Treatment 2 (T2) in each farm. T1 utilized sorting sieves while T2 used hand manual sorting. Broodstocks of 1500 ± 10.52 g were used for breeding. Fertilized eggs were shared weight for weight between T1 and T2 and normal management procedures were followed. Sorting of fish were done on the 14th, 21st, 28th, 42nd, 56th and 70th day after hatching. The percentage hatching was high, 78.33 ± 4.08% and 76.92 ± 3.19% in T1 and T2 respectively but not significant (P ˃ 0.05). 70.76 ± 6.70% (T1) and 60.69 ± 7.52% (T2) fry survived to fingerling stage in the 6th week. Survival rate from fingerlings to juveniles at the 10th week significantly (P ˂ 0.05) reduced to 62.33 ± 12.73% (T1) and 40.55 ± 8.44% (T2) respectively. At harvest (10th week), there were more numbers of small (4 – 6 cm) and large (8 – 12 cm) sizes of juveniles in T2 than T1 whereas numbers of medium (6 – 8 cm) size juveniles in T1 almost doubled that of T2 at a significant level (P ˂ 0.05). Economic analysis of the trial gave Marginal Rate of Return (MRR) of N5.50k in favour of T1. It was concluded that introduction of sorting sieves to catfish hatchery will reduce drudgery in fry sorting while increasing percentage survival and profitability at the same time.