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Abstract

Lake Ehuikro is used to supply drinking water to Bongouanou City. Some human activities around the lake are established and may have an effect on water quality and aquatic life. This study was conducted to describe for the first time the diversity and the structure of macro-invertebrate communities in this area. Physico-chemical parameters were measured monthly in three sampling sites and the benthic Macroinvertebrates was collected using a Van Veen grab on a total area of 0.5 m 2 per sample. Principal component analysis showed a clear pattern of separation of these three sampling sites according to the substrate type: gravelmud, sand-gravel and sand in E1, E2 and E3 stations, respectively. A total of 3285 aquatic Macroinvertebrates belonging 52 taxa, were recorded and the most dominant taxa were Baetis sp. (19.85%) and Tubifex sp. (11.57%). Multivariate statistical analysis revealed significant differences between the community structure of E1 and E2 samples: the first sample was dominated by 7 taxa including Tubifex sp. and Melanoides tuberculata while the second by 13 species. The Shannon diversity indices showed high value in lake (3.10) reflecting moderately polluted conditions. Significant correlations between Tubifex sp., Biomphalaria pfeifferi, M. tuberculata and depth, transparency, substrate texture and macrophyte (MAC) were found. The present study revealed that the benthic fauna of the lake Ehuikro dominated by pollution-sensitive taxa. These findings provide valuable information that can be used to establish biotic indices to monitor the human disturbance effect on water quality of Lake Ehuikro.

Structure of Benthic Macroinvertebrate Assemblages in Azagny Channel (Côte d’Ivoire)

“…Macroinvertebrates were sampled monthly using a Van Veen grab, 1 m long and 14 cm in diameter as described by [4,18]. In each sampling station, ten random replicate samples were taken at each station from various habitats, for a total area of 0.5 m 2 .…”

“…Numerous studies have reported that spatial distributions of aquatic organisms are affected by various environmental variables at rivers, estuaries and lagoons [3,4]. Such is the case for benthic macroinvertebrates which are often found attached to rocks, vegetation, logs and sticks or burrowed into the bottom sand and sediments.…”

“…Human activities are limited in Azagny Channel but it is influenced by anthropogenic impacts of Ebrié lagoon and Bandama estuary. Several studies have shown a pollution status of water and sediment of these water bodies [9,10,11], which may have an impact on benthic macroinvertebrates diversity of Azagny Channel, because it has been reported that altering the sedimentary environment reduces macroinvertebrates species richness and diversity [4,12]. In addition, the PNA water bodies receive a significant amount of runoff from the watershed, and these waters carries a large quantity of organic matter and its accumulation in water bottom can change macroinvertebrate habitats [10].…”