Habitat Quality and Fish-Based Biotic Integrity Indices of River Kathita and Associated Dams: Implications for Ecosystem Management and Biodiversity Conservation

Anthropogenic activities are increasingly threatening rivers worldwide by altering their biogeochemical processes and compromising their ecological integrity, necessitating robust assessment methods. This study documented biotic integrity, based on fish population dynamics and habitat type in River Kathita and its associated dams, from March to August 2020 at 11 sampling sites. In-situ physicochemical parameters were determined using a YSI multiparameter meter, and nutrients were determined using standard methods. Habitat quality was determined based on 9 metrics of Habitat Quality Index. Fish populations were sampled using electrofishing supplemented by gill nets, traps, and long lines where applicable. The collected fish were subsequently identified to species and classified into the following ecological guilds: native, exotic, tolerant, intolerant, and rheophilic. A total of 1,133 individuals and 20 species of fish were sampled and determined for the project. The habitat quality index means score ranges from S1 (21.00 ± 0.73) to S3 (12.17 ± 0.31). The fish-based Index of Biotic Integrity (FIBI) scores from all sites indicate degraded conditions, with FIBI means ranging from S1 (35.33 ±2.72) to S3 (27.00 ±1.13). The results of the HQI and FIBI demonstrated that upper Tana River system and its tributaries are ecologically degraded. These results provide baseline data for continued monitoring and help develop targeted strategies for sustainable ecosystem management and biodiversity conservation