Effects of Illumination on Egg Hatching and Fertilization of Clarias gariepinus (Burchell, 1822)

The effect of light condition on fertilization and hatching of eggs on artificially induced Clarias gariepinus was investigated. The eggs were dry-stripped and subjected to three light conditions, namely low illumination, medium illumination, and high illumination. Equal numbers of eggs were incubated in the three hatcheries in triplicates. The experiment was conducted in 3×3 completely randomized design. Data generated were subjected to Analysis of Variance (ANOVA). Egg fertilization was significant (p<0.05) among the treatments. The highest fertilization rate was achieved in medium hatchery light condition (65.2%). Fertilization rate of 61% and 53% were achieved in high and low hatchery light condition respectively. Fertilization rate among the hatcheries were highly significant (p<0.01). Highest egg hatching percentage (79%) was achieved under high hatchery light condition. Hatching percentage of 64 and 63 were recorded in low and medium hatchery light conditions respectively. The findings here suggest that light could affect egg fertilization and hatching in Clarias gariepinus. The study further suggested that the effect of light was stronger in egg hatching than in egg fertilization. Key Words: Light, fertilization, hatchability and Clarias gariepinu