GIS-Based Aquaculture Spatial Suitability in Western Amazonian Hydroelectric Reservoirs

Abstract

This study applies a GIS-based approach to evaluate the spatial suitability of net-cage aquaculture and analyse key water quality parameters in four hydroelectric reservoirs located in the Jamari River basin, Western Brazilian Amazon. The assessment includes one large hydropower reservoir (HPP Samuel) and three small hydropower reservoirs (SHDs): SC Monte Negro, Jamari and Canaã. The methodology followed five stages: (1) temporal analysis of Total Water Surface Area (TWSA); (2) identification of vegetation-free areas; (3) evaluation of depth suitability; (4) compilation of historical water level data and limnological parameters (chlorophyll-a, BOD, total phosphorus, dissolved oxygen); and (5) mapping and estimation of Potential Aquaculture Sites (PAS). Due to excessive seasonal variation (> 70% fluctuation in TWSA), the Samuel HPP reservoir was excluded from the final suitability mapping. In contrast, the SHD reservoirs exhibited environmental stability and fulfilled legal requirements for net-cage installation. Together, they offer an estimated production potential of up to 466 t per year using native species such as Colossoma macropomum. Most water quality parameters complied with Brazilian environmental standards (CONAMA Resolution no. 357/2005). This spatial and limnological assessment provides a technical foundation for implementing sustainable aquaculture systems in Amazonian hydroelectric reservoirs. Further studies should incorporate ecological carrying capacity modelling and environmental impact projections to support long-term sustainable aquaculture practices in these freshwater ecosystems.