Abstract

This study investigated the utilization of periphyton by Clarias gariepinus stocked in aqua dams with net (N), plastic (P), and stone (S) substrates. Three feeding regimes were designed. In the first feeding regime, the fish were fed twice a day, every day and designated as N100, P100, and S100. In the second regime, the fish were fed every other day, designated as N50, P50, and S50. In the third feeding regime, the fish were fed every third day, designated as N33, P33, and S33. The periphyton abundance was significantly different across all substrates, with the net substrate registering the highest abundance (R = 0.4108, P = 0.0001; ANOSIM). Microcystis spp. and Chlorella spp. were the most abundant and dominant across all substrates. However, the fish selectively fed on insects and Chironomidae larvae. Diatoms, Difflugia spp., and Microcystis spp. dominated the fecal matter. High growth rates comparable to the control were observed in fish fed every third day in aqua dams with stone (S33). The large lower jaw extensibility (132 ± 25.88%) enabled the catfish to scoop periphyton from the stone substrates. Based on the observed high growth rates and effective periphyton utilization, it is recommended that African catfish be cultured in periphyton-based aquaculture with stone substrates.

Key words: African catfish, Periphyton, Aqua Dams, Substrates, Utilization