Diversity of Chironomidae, in Relation to Pollution of the River Niger at Niamey, Niger

This paper presents the first results on the quality of the River Niger at Niamey based on the Chironomidae infestation of its water. Two sampling methods were used for collecting the chironomid larvae and included use of hand net of 500 >m mesh-size and artificial substrata of stones covered with galvanized wire netting. Water samples were subjected to physicochemical analysis. Twenty taxa of chironomidae were collected. Among these, Chironomus gr. plumosus represented 51% and Microchironomus sp. 18% of all larvae collected. The distribution of Chironomidae throughout the river showed differences between the sampling stations. Organic pollution and nutrients loading were the main factors explaining the differences in spatial distribution. Chironomus gr. plumosus and Microchironomus sp. were positively correlated to those factors, while others as Tanytarsini, Nilodosis sp., Micropelopinae and Procladius sp. were negatively correlated. According to these results, Chironomidae diversity could be a useful tool for the assessment of the biological quality of the River Niger at the study site.Keywords: Chironomidae, River Niger, water quality, pollution, Niger