Food habits of fishes and food trophic organizations of the Sô River in Benin

Abstract

The study of food habits of fishes and Food Trophic Organizations was undertaken on the So River in Benin. Fish were sampled monthly over an annual period from October 2015 to November 2016. In total, the stomach contents of 991 fish specimens belonging to 14 species were analyzed in the laboratory. This analysis shows that 9 preys were generally consumed by the fish of So river, namely: fish fry, insect larvae, aquatic insects, molluscs, shrimps, plant debris, detritus, phytoplankton and zooplankton. Three main consumer groups have been defined, namely piscivores, benthivores and detritivores. The upper reaches of the river showed a complexity of the trophic relationships dominated by the zoophagous species (piscivores, benthivores) which represent 83% of the abundance weigth of ichthyofauna; while the lower and middle courses of the river subjected to anthropogenic pressures were dominated by a high proportion of the detritivores which represent 42.7% of the abundance in weigth of ichthyofauna.