Damming Amazon Rivers: Environmental impacts of hydroelectric dams on Brazil’s Madeira River according to local fishers’ perception

Abstract

This study aimed to investigate the environmental impacts generated by the hydroelectric complex in the Madeira River, Brazilian Amazon, based on the perceptions of local fishers and fishery database, it focus attention on three main impacts: (i) on local fishery stocks; (ii) in fish fauna and (iii) on the aquatic ecosystems. The local fishers were selected through the ''snowball'' approach for the application of semi-structured interviews. All the local fishers confirmed having perceived a decline in fishery productivity following the impounding of the Madeira River. Changes in the condition of the fish were also perceived by the local fishers, including exophthalmia (82%), a reduction in the weight or length of the fish (25%), and irregular breeding patterns (14%). In the case of impacts on the river, changes in the hydrological cycle were the process remembered most frequently (75%). The results elucidated a range of environmental impacts caused by the hydroelectric dams of the Madeira River.

Hydroelectric Dams From Madeira River Seasonally Impacts the Fisheries Production in the Guaporé Basin (Rondônia, Brazil)

“…However, migrating species, such as large catfish of the genus Pseudoplatystoma and include cachara and caparari, are the most affected by the anthropization of aquatic environments (Santos et al, 2020). Nevertheless, in the present study these species showed high production in the post-damming period during the low water phase.…”

Hydropeaking Operations of Two Run-of-River Mega-Dams Alter Downstream Hydrology of the Largest Amazon Tributary

“…But results from a recent ethnobiological study suggest that it is possible that the increased hydropeaking reported here is leading to important socio-ecological consequences downstream of the Madeira dams. Local fishers perceive changes to natural flow regimes as the most negative impact of the Madeira dams (Santos et al, 2020). More specifically, fishers contend that sudden variations in river levels (locally known as "repiquetes") are the most relevant hydrologic impact of the Madeira dams.…”

“…More specifically, fishers contend that sudden variations in river levels (locally known as "repiquetes") are the most relevant hydrologic impact of the Madeira dams. Some fishers argue that the increased irregularity and unpredictability of the flow regime caused by hydropeaking negatively affect fish catches; according to them, catches increase when river levels begin to fall, and then decrease when the dam releases water (Santos et al, 2020).…”

‘Taking Fishers’ Knowledge to the Lab’: An Interdisciplinary Approach to Understand Fish Trophic Relationships in the Brazilian Amazon

“…Such information from fishers' LEK, which can be mixed or incorporated into conventional research data, can be an important source for creating new ecological hypotheses (Silvano and Valbo-Jørgensen, 2008;Turvey et al, 2010). Among its many applications, fishers' LEK can contribute to identify environmental changes and assess impacts from development projects on fisheries resources (Hallwass et al, 2013;Baird et al, 2020;Runde et al, 2020;Santos et al, 2020), to calculate fish trophic level and to indicate patterns of mercury bioaccumulation in fish (Silvano and Begossi, 2016), besides providing needed data on the abundance patterns, occurrence and distribution of threatened species (Bender et al, 2014;Zapelini et al, 2017;Lopes et al, 2018;Freitas et al, 2020;Hallwass et al, 2020b;Ribeiro et al, 2021).…”