International Journal of Biology Reports

fa Assessment of Fish Composition and Ecological Indices in the Southern Huwaiza Marsh, Iraq عمومى General پژوهشي Research This study aimed to assess fish species composition, dominance, and key ecological indices (diversity, evenness, richness, and similarity) in the southern part of Huwaiza Marsh, Iraq. Sampling was conducted at Al-Safya site, which is connected to Al-Suwaib River and Shatt Al-Arab River, during the dry season (June–August) and wet season (February–May). Fish were collected using fixed gill nets (2.5–10 cm mesh size) and electrofishing. During the dry season, 10 species from five families were recorded, with native species representing 80% and alien species 20% of the total. Seven commercial species accounted for 70% of the catch. In the wet season, 11 species were recorded, with 72.7% native and 27.3% alien species; six commercial species made up 54.5% of the total. Cyprinidae was the dominant family in both seasons. Ecological indices showed seasonal fluctuations. During the dry season, the Shannon diversity index (H) averaged 1.81, richness (D) 1.57, and evenness (J) 0.89. In the wet season, H averaged 1.39, D 1.30, and J 0.67. Higher diversity and evenness were observed in the dry season compared to the wet season. These results highlight seasonal variations in the fish community structure and provide baseline data for future conservation and management of the Huwaiza Marsh ecosystem.   Fish composition, Ecological indices, Seasonal variation, Huwaiza Marsh, Iraq 37 49 http://injbir.com/browse.php?a_code=A-10-1-38&slc_lang=fa&sid=1 N.S. Salman 1003194753284600602 1003194753284600602 Yes Al-Warka University College S.S. Hassan 1003194753284600603 1003194753284600603 No Al-Maqal University, Basra, Iraq M.M. Taher 1003194753284600604 1003194753284600604 No Department of Fisheries, University of Basra, Iraq