Response of benthic macroinvertebrates communities to seasonal changes in the Grand-Lahou lagoon (Côte d’Ivoire, West Africa)

Document Type: Primary Research paper

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Abstract

The response of benthic macroinvertebrates communities to seasonal changes was studied in the Grand-Lahou lagoon (Côte d’Ivoire, West Africa). The organisation of macroinvertebrates was recorded at eight (8) stations across the whole lagoon in four seasons (the Long Rainy Season (June 2006), the Short Dry Season (September 2006), the Short Rainy Season (November 2006) and the Long Dry Season (March 2007)).Each faunal sampling was coupled with in situ measurements of abiotic parameters and samples were also collected for granulometry analyses. A total of 1 747 individuals representing 54 taxa belonging to 27 families and 7 orders of benthic macroinvertebrates were identified during this study. Of this number of taxa, molluscs constituted 37.03%, crustaceans 35.18% and polychaetes 24.07%. Other taxa recorded included oligochaetes and undetermined, together constituted 3.7%. The distribution patterns of density and diversity over seasons in the Grand-Lahou lagoon indicated periodic changes ranging from rich community during the Long Rainy Season to impoverished one in the Long Dry Season. However, these variations were not significantly different.Temperature, dissolved oxygen, pH, water depth and percentage of fine and coarse sand in that order were the major significant variables structuring the macroinvertebrates assemblages in the Grand-Lahou lagoon.

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