Effect of Photoperiod on Spawning Response of African Catfish in Controlled Hatchery Conditions

This study investigated the effect of controlled photoperiod manipulation on the spawning response and reproductive performance of African catfish (Clarias gariepinus) broodstock under hatchery conditions in Kwara State, North Central Nigeria. Reliable and predictable spawning induction is critical for maintaining consistent fingerling supply in Nigerian catfish hatcheries. Broodstock were divided into three photoperiod treatment groups: natural light (12 hours light to 12 hours dark), extended light (16 hours light to 8 hours dark), and reduced light (8 hours light to 16 hours dark), with each group managed in fibreglass tanks over a six-week conditioning period. Hormone induction using crude carp pituitary extract was applied at the conclusion of the conditioning period. Reproductive parameters assessed included latency period, ovulation rate, fertilisation rate, hatching rate, and larval survival at 72 hours. Results showed that broodstock subjected to natural photoperiod achieved the highest fertilisation rate of 82 percent and hatching rate of 76 percent, while reduced light conditions significantly delayed ovulation and reduced fertilisation success. Extended photoperiod produced intermediate results, with evidence of heightened feeding behaviour and improved broodstock body condition during the conditioning period. Ovulation occurred in 90 percent of females across all groups following hormone induction, confirming the effectiveness of pituitary extract regardless of photoperiod. The study recommends natural photoperiod maintenance for routine hatchery operations, with light manipulation explored further as a tool for off-season spawning induction. Keywords: photoperiod, Clarias gariepinus, hatchery, spawning induction, broodstock management