Food and Feeding Habits of Labeo coubie (Rüppell, 1832) and Labeo senegalensis (Valenciennes, 1842) (Cypriniformes: Cyprinidae) in the Lower Orashi River, Niger Delta, Nigeria

Abstract

Understanding the diet and feeding relationships of riverine fishes underpins sustainable exploitation and aquaculture development. This study examined the food and feeding habits of Labeo coubie and Labeo senegalensis (Cyprinidae) in the lower Orashi River, Engenni, Ahoada-West Local Government Area, Rivers State, Nigeria, using gut content analysis of fish sampled monthly from four stations (July 2022 to June 2023). The guts of 200 specimens (100 per species) were examined; 15 were empty (3% in L. coubie, 12% in L. senegalensis) and food items were quantified using the numerical method, frequency of occurrence and the index of feeding significance. Seven food categories were identified across both species. Rotifera (Keratella sp. and Philodina sp.) dominated the diet of L. coubie (46.77% by number, 41.24% by occurrence), followed by Arthropoda (32.24%, 38.14%) and detritus (16.69%, 16.50%). Bacillariophyta dominated the diet of L. senegalensis (50.0%, 52.27%), followed by Arthropoda (20.60%, 21.59%) and Chlorophyta. A chi-square test confirmed the species differ significantly in diet composition (χ² = 964.8, df = 6, p < 0.001), and Schoener's overlap index was low (Cxy = 0.27), well below the 0.60 threshold. Detritus and sand in the guts, together with the inferior mouth position of both species, indicate a bottom-feeding, omnivorous feeding strategy. These findings support low trophic competition between the two congeners through resource partitioning, and confirm the suitability of both species for pond aquaculture. Continued, season- and size-resolved gut-content monitoring is recommended to track dietary shifts that could inform ecosystem-based fisheries management in the Niger Delta.