African Aquatic Resource Management (Fisheries/Aquatic/Environmental): a comparative evidence study of ENT pathways, implementation constraints, and policy implications in Africa

Excess nutrient transport from fertilised fields to inland fisheries remains poorly differentiated across African aquatic resource systems, where eutrophication, siltation and seasonal hypoxia constrain both capture fisheries and pond aquaculture despite contrasting hydrologies. This methodological proposal reframes ENT pathways as three transport mechanisms—surface wash, subsurface leaching and channel-coupled delivery—whose relative importance varies with landscape and governance context. It develops a transferable geographic information systems procedure centred on a composite spatial index combining Slope, Drainage density, Rainfall intensity, Land cover, Soil permeability, Elevation and Distance to channels, illustrated for South Africa with comparative extension to other African basins. Figure 1 delineates the administrative units of South Africa that structure the analysis, Figure 2 is designed to integrate regional distribution, kernel-density hotspots, service coverage buffers and settlement connectivity, and Figure 3 presents the proposed criterion weights with uncertainty. The contribution is bounded to a reproducible prioritisation logic rather than a completed susceptibility map, offering fisheries and agricultural agencies a transparent basis for targeting buffer restoration, fertiliser management and co-management agreements.