Available online Aug 21, 2025.

[ Original ] Volume 31, Issue 4, 2025, Pages 795-803

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Abstract

Freshwater biodiversity in Nigerian tropical rivers faces increasing threats from environmental changes and human activities, yet detailed knowledge of fish community dynamics remains limited. This study aimed to characterize species composition, monthly abundance fluctuations, and ecological drivers of fish communities in the Great Kwa River, Cross River State, Nigeria, from January to December 2024. Fish were sampled monthly using standardized nets at two stations, and environmental parameters were concurrently measured. Data were analyzed for species relative abundance, diversity indices, dominance patterns, and relationships with environmental variables using Canonical Correspondence Analysis (CCA). Results showed that Chrysichthys nigrodigitatus and Ethmalosa fimbriata dominated the community, comprising 40.5% and 23.8% of total abundance, respectively. Species richness ranged from 13 to 18 species monthly, with evenness peaking at 0.80 in May. Abundance and dominance of key species peaked during the wet season months (May and July). CCA revealed strong positive associations between dominant species and higher water temperatures and lower transparency typical of the wet season. The study highlights significant seasonal dynamics driven by environmental factors and emphasizes the need for adaptive management strategies to conserve biodiversity and sustain fisheries in tropical river ecosystems.

 

Keywords

Freshwater biodiversity, Fish community dynamics, Tropical river, Species dominance, Great Kwa River, Nigeria,

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