Fish Species Composition and Diversity Assessment in the Roseries Reservoir, Sudan

This study aimed to investigate fish diversity and species structure in the Roseries reservoir on the Blue Nile (Sudan). A total of 1,185 fish specimens were collected using gill nets mesh size between (2-8 cm), through monthly sampling at four sites: Awal Bab, El-Regiba, Kerma, and Wad El-Mahi, over a period of one year, from November 2021 to November 2022. 26 species were identified across 19 genera and 13 families, with Mochokidae being the most dominant family, followed by Cyprinidae and Alestidae. The comparisons of diversity indices indicated the highest similarity between Kerma and El-Regiba (H' = 0.333). The Index of Relative Importance (IRI) also highlighted significant variations among species. In Awal Bab, Labeo senegalensis had the highest IRI at 32.36, and Synodontis schall was dominant in Wad El-Mahi with an IRI of 78.66. This study indicated that S. schall had the highest IRI across all sites at 41.426. Species richness was lower in El-Regiba and Kerma compared to Awal Bab and Wad El-Mahi. This research generates essential baseline information to support science-based fisheries management and ecosystem conservation efforts in the Roseries reservoir.