Feeding habits of Hippopotamyrus pictus and Cyphomyrus psittacus (Mormyridae; Teleoostei) in Bagoe River (Côte d’Ivoire)

Abstract

The feeding habits of Hippopotamyrus pictus and Cyphomyrus psittacus were investigated to determine the trophic relationships in the both species. The stomach contents of 97 Hippopotamyrus pictus and 72 Cyphomyrus psittacus were collected during 4 sampling periods from April 2010 and November 2012 in Bagoe River of Côte d'Ivoire. Vacuity Index of Hippopotamyrus pictus and Cyphomyrus psittacus showed 13.4% and 22.22% of stomachs respectively. Food items were identified to the minimum taxon possible. The importance of the different prey types was assessed using the index of preponderance for both species. The results indicated that the composition of the prey ingested varied with species. Hippopotamyrus pictus consumed 23 prey items and Cyphomyrus psittacus consumed 17 prey items with 16 items shared by both species. The Chironomidae was principal prey of the 2 species. Hydroptilidae was the secondary prey of Cyphomyrus psittacus. In this fact, the diet of Hippopotamyrus pictus varied with size fish and seasonally. The Syrphidae was secondary prey of juvenile and Macrophytes was secondary prey of adults. In wet season, Hippopotamyrus pictus fed exclusively of Insects. Insects and Macrophytes were more important during dry season. In terms of the diversity of items, the Shannon index was higher at Hippopotamyrus pictus than Cyphomyrus psittacus. Schoener coefficient values (α = 0.99) indicated the high overlap.