Providing adequate food for the rapidly increasing human population is one of the greatest challenges in the world. So, in addition to increasing food production from agriculture, it is necessary to sustainably exploit the aquatic ecosystems to ensure food security by virtue of their high productivity. Fisheries management strategies require different ecological and physiological studies of fish to apply effective management tools and feeding habit. The main objective of this study was to generate recent baseline information on the food and feeding habits of African catfish in lake Koka, Ethiopia for better utilization of the catfish fishery and aquaculture. The food and feeding habits of Clarias gariepinus in Lake Koka, Ethiopia was studied from March to July, 2018. The adults were purchased from local fishermen at three landing sites and the juveniles were collected through sampling using beach seine net from three sampling sites selected based on different criteria. A total of 402 fish samples ranging from 29- 65 cm in total length and 95- 1420g total weight, respectively were collected during the study. Results: The relation between total length and total weight of C. gariepinus was curvilinear (Tw= 0.0067TL2.948) with a strong relationship (R2 = 0.978). The “b” value was 2.948 which is closer to the theoretical isometric growth value (b= 3). Out of the 402 fish examined, 59 (14.7%) had empty stomachs while 343 (85.3%) contained food. Fish samples that contained food in their stomach were analyzed using frequency of occurrence and volumetric analysis methods. The major food items in the stomach of were zooplankton (20.76%), insects (18.32%), detritus (16.34%) and macrophytes (14.13%) volumetrically. The volumetric contributions of insects (29.09%), zooplankton (25.64%) and phytoplankton (7.19%) were higher during dry months (March and April) than the wet months (June and July) while the importance of detritus (22.84%) and Macrophytes (24.28%) was relatively higher during the wet months than the dry months (10.67% and 7.74%), respectively. The contributions of zooplankton, detritus and fish in the diet of the species increased with its size while the importance of insects, macrophytes and phytoplankton decreased as the size of the fish increased which indicates ontogenetic dietary shift in the species. Effective management of the lake biodiversity should be given priority to maintain the catfish fishery on a sustainable basis.

Keywords: Feeding habit, Lake Koka, Ontogenetic dietary shift