Impact of artisanal and clandestine gold mining on the distribution of the Monogeneans gill parasite of Clarias gariepinus in the Bagoué river (Côte d’Ivoire)

Abstract

A study of the spatial distribution of Monogeneans on the gills of 272 specimens of Clarias gariepinus collected in the Bagoué River was conducted from August 2020 to July 2021. This study compared the distribution and microhabitat of parasites between the upstream reference zone, not impacted by gold panning (zone I) and the downstream zone heavily impacted (zone II) of the Bagoué River. Branchial analysis identified eight species of Monogeneans parasite in reference zone and five species in impacted zone. Results showed that the prevalence and mean intensity were relatively higher in reference zone than in impacted zone. In reference zone, the preferred habitats of Monogeneans were the gill arches I and II with an affinity for the dorsal segments. In contrast, in impacted zone, they preferred gill arches II and III with an affinity for medial segments. This study demonstrates that artisanal gold mining influenced the diversity and repartition of monogeneans gill parasite of C. gariepinus.

Key words: Monogeneans, pollution, gold panning, Clarias, distribution, Bagoué River