Spatio-Temporal Variations in Water Quality and Fish Assemblages in Odoponyi Seasonal Stream as a response to disturbance from Selected Agricultural Landscapes in Tororo, Uganda

Abstract

This study investigated the Spatio-Temporal Variations in Water Quality and Fish Assemblages in Odoponyi Seasonal Stream as a response to disturbance from Selected Agricultural Landscapes. Six sampling campaigns were launched at three different landscape sampling sites (grazing, rice plantation and sugarcane plantation) for 12 months from January to December of 2022. There was a general trend of increase in Dissolved Oxygen from upstream to downstream in sites in the catchment during both dry (from 7.13±1.9 to 8.9±2.1ppm) and wet seasons (from 11.2±2 to 12.3±01ppm). Plantation landscape of sugarcane registered the highest concentrations of nitrates during both dry and wet seasons (8±0.9 Mg/l and 11±1Mg/l) respectively. There was higher water transparency during dry season than wet season. A total of 568 fish individuals belonging to 7 species including Clarias leocephalus, Pamiphals promelas, Notemigonus crysoleucus, Anchoa mitchili, Poecilia reticulata, Barbodes binotatus and Pseudorasbora parva were captured using hand line and seine nets. Fish species diversity, richness and abundancy were higher during the wet season than dry season. Sugarcane plantation landscape registered the highest fish catch during both dry and wet season while grazing landscape registered the lowest catch at all times. This study recorded presence of a rare migratory fish species Notemigonus cryseleucus in wet season. We concluded that Odoponyi stream has migratory fish species that require protection especially during wet season. We recommended that land users in the catchment should leave a buffer strip of about 10m from the stream bank to reduce on the effect of erosion deposition directly into the stream.