Author(s): Diyaolu D.O

Abstract: This study estimated quantitatively and qualitatively the aerobic bacterial flora associated with early developmental stages of African catfish Clarias gariepinus during artificial propagation in a hatchery in Nigeria. Eggs hatchability and larval survival during the propagation were also monitored. The results obtained showed that the total number of colony-forming units per gram (cfu/g) for ova, fertilized eggs, hatchlings, fry and advanced fry ranged from 2.83±0.38x103 to 4.23±0.49x103, 6.73±0.10x103 to 1.27±0.3x104, 6.00±0.40x104 to 8.57±1.62x104, 9.00±2.17x104to 3.27±1.46x105 and 9.00±2.17x105 to 1.6±0.56x107, respectively. The numbers of bacteria on the fish eggs, hatchlings, fry, and advanced fry were higher than those found in their respective culture water. In all, eight bacteria genera, consisting of Aeromonas, Bacillus, Chromobacterium, Citrobacter, Escherichia coli, Klebsiella, Proteus and Salmonella, were identified. Mortalities were observed in all stages of growth, with the highest losses occurring as the fish grew from hatchlings to fry.

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