Optimization of artificial insemination outcomes of African catfish (Clarias gariepinus) with differing hatchery conditions.

The African catfish is one of the most promising warm-freshwater species for aquaculture development in the upcoming years, although there are two primary limitations in its production: less-than-desirable survival rates and low larvae quality. In this study, a novel method of egg fertilization for this species was evaluated which has already been successfully utilized in the production of other finfish. The results indicate that dividing the semen designated for fertilization of eggs into smaller aliquots and adding it to the eggs at 30 s intervals (i.e., 0, 30 and 60 s), after activation of the eggs with water, increased the hatching rate percentage (97.1%) compared to control groups (87.9%) in which the entire portion of semen was added to eggs at the time of water addition for egg activation. Results with repeated evaluations in the field confirmed that eggs with greater biological quality were fertilized at a similar rate using the modified and control methods for fertilization, although when the eggs were of a lesser biological quality, the fertilization rate was greater using the modified methods than the control methods.