Fishers' Knowledge Indicates Extensive Socioecological Impacts Downstream of Proposed Dams in a Tropical River

Brazil's hydroelectricity sector is rapidly expanding, and several dams are planned in Amazonian rivers. The impacts on the fisheries downstream of the dams have largely been overlooked by official impact assessments. Here, we gather fishery baseline data from interviews with 171 fishers in 16 communities along a similar to 275-km stretch of the Tapajos River, located downstream of a proposed dam. The results indicate that fishing constitutes a key source of food and income for fishers and their communities and that the impact of the dam on the fisheries will potentially extend much further than the officially recognized affected area. By ignoring the effects of the dams on downstream communities, impact assessments have severely underestimated the number of people who would be affected by the dams. Therefore, a thorough evaluation of downstream fishers needs to be conducted prior to river impoundment and be considered by development plans.