Effect of Different Ages of African catfish (Clarias gariepinus) Broodstock on Reproductive Performance and Fries Production

Abstract

This study was conducted at the hatchery complex of Akwa Ibom State University to investigate the effect of different ages of African catfish (Clarias gariepinus) on their reproductive performances. Eighteen (18) broodstock of Clarias gariepinus (3 males and 3 females) from each age group, six months, twelve months and eighteen months old with average body measurement of 1.1kg and 32cm for six month, 1.8kg and 43cm for 12 months and 2.5 kg and 65.7cm for 18 months were selected from AKSU fish farm labeled treatment A, B and C for the study. 3 male broodstock from each treatment were sacrificed for milt extraction without hormonal inducement. The milt from each treatment were separately pooled into one volume and divided into three portions each diluted with 2ml of normal saline solution. Three female broodstock from each treatment were separately induced with ovaprim at a single dosage of 0.5ml/kg body weight of fish and allowed for a latency period of ten hours at water temperature of 26oC before stripping manually. 3g of egg from each broodstock was mixed with the diluted milt and activated with 100 mls of normal saline. The fertilized eggs were incubated in aerated indoor concrete tanks in 3 replicates. % fertilization were accessed six (6) hours after incubation, % hatchability was accessed twenty-six hours (26) after incubation, while the percentage survival and fry production success in each treatment was accessed after ten (10) days post hatching. The results reveal that the reproductive parameters considered in this study significantly (p<0.05) increased with age of broodstocks. The percentage fertilization of egg from the least to the oldest broodstock were 63.67± 0.88, 69.50 ± 0.87 and 81.83 ± 5.05 respectively. The percentage hatchability of the oldest broodstock was 82.62 ± 1.6 significantly (P< 0.05) higher than 64.79 ± 2.74 (12 months) with the least value of 49.04 ± 5.76 recorded for six-month-old broodstock. The oldest broodstock had the highest percentage survival 83.14 ± 3.16 and fry production success of 56.05± 0.06 while the least broodstock (6-month-old) had the least value of survival 54.59 ± 2.42 and fry production success of 17.17 ± 2.59%.