Water Hyacinth Infestation and Its Effect on Fish Production in River Benue, Benue State

Water hyacinth (Eichhornia crassipes) invasion poses severe ecological and economic consequences for freshwater fisheries in tropical Africa, including Nigeria's inland water bodies. This study assesses the spatial extent of water hyacinth infestation in the River Benue within Benue State, North Central Nigeria, and evaluates its effects on fish production, dissolved oxygen levels, and artisanal fishing operations. Satellite imagery from Sentinel-2 acquired between 2021 and 2024 is classified using maximum likelihood algorithms to quantify infestation area at biannual intervals. Field surveys at six river sections between Makurdi and Gboko document canopy density, mat depth, and associated hydrological impacts. Dissolved oxygen profiles beneath dense mats are measured using multiparameter probes, and the oxygen deficit zone is related to observed fish mortality events recorded by local fishing communities. Artisanal fishers are interviewed to document changes in catch composition, species availability, and gear loss attributable to weed infestation. Daily catch records maintained by three fishing cooperative societies provide quantitative data on production trends over four years. Findings are expected to correlate increased infestation cover with significant reductions in catch-per-unit-effort for demersal species and partial displacement of fishing effort to uninfested river sections. Recommendations include coordinated mechanical control, biocontrol using Neochetina weevils, and community-based weed surveillance programmes. Keywords: water hyacinth, River Benue, freshwater fisheries, invasive species, dissolved oxygen