A barrier to upstream migration in the fish passage of Itaipu Dam (Canal da Piracema), Paraná River basin

Abstract

The majority of the fish passages built in the Neotropical region are characterised by low efficiency and high selectivity; in many cases, the benefits to fish populations are uncertain. Studies conducted in the Canal da Piracema at Itaipu dam on the Parana River indicate that the system component designated as the Discharge channel in the Bela Vista River (herein named Canal de deságue no rio Bela Vista or CABV), a 200 m long technical section, was the main barrier to the upstream migration. The aim of this study was to evaluate the degree of restriction imposed by the CABV on upstream movements of Prochilodus lineatus and Leporinus elongatus, Characiformes. Fish were tagged with passive integrated transponders (PIT tags) and released both downstream and upstream of this critical section. Individuals of both species released downstream of the CABV took much more time to reach the upper end of the system (43.6 days vs. 15.9 days), and passed in much lower proportions (18% vs. 60.8%) than those tagged upstream of this component. Although more work is needed to differentiate between fishway effects and natural variation in migratory motivation, the results clearly demonstrate passage problems at the CABV.A maioria dos sistemas para transposição de peixes implantados na região Neotropical caracteriza-se por baixa eficiência e seletividade, em muitos casos com benefícios questionáveis para as populações de peixes. Estudos conduzidos no Canal da Piracema, localizado na barragem de Itaipu, rio Paraná, apontaram como principal barreira à migração ascendente o componente do sistema denominado Canal de deságue no rio Bela Vista (CABV), uma seção de escada com 200 m de extensão. Este estudo teve por objetivo avaliar o grau de restrição imposto pelo CABV aos movimentos ascendentes de Prochilodus lineatus e Leporinus elongatus, Characiformes. Os peixes foram marcados com Passive Integrated Transponders (PIT-tags) e soltos a jusante e a montante do CABV. Indivíduos de ambas as espécies de jusante do CABV levaram muito mais tempo para atingirem a extremidade superior do sistema (43,6 dias vs. 15,9 dias) e passaram em muito menor proporção (18% vs. 60,8%) do que os marcados a montante desse componente. Embora sejam necessários outros trabalhos para a distinção entre os efeitos do sistema de transposição de peixes e a variação natural da motivação migratória, os resultados demonstram claramente que existem problemas na passagem pelo CABV.

Factors Influencing Movements of Two Migratory Fishes within the Tailrace of a Large Neotropical Dam and their Implications for Hydropower Impacts

“…In recent years, telemetry has become a powerful tool to understand how fish respond to dams and attempts to manage fish passage in Brazil. Most studies have been directed towards solving one of the biggest concerns in fish conservation, the efficacy of fish passage for migratory species (Pompeu and Martinez, ; Agostinho et al , ; Fontes Júnior et al , ; Wagner et al , ). Other studies have addressed the migratory behaviours of selected Neotropical species (Godinho and Kynard, ; Godinho et al , ; Hahn et al , ).…”

Predicted impacts of proposed hydroelectric facilities on fish migration routes upstream from the Pantanal wetland (Brazil)

“…Both observations come from the Paraná River Basin, which borders the PHB to the southeast and is part of the larger Paraguay-Paraná Basin. A fish ladder on the Itaipu Dam, in the Paraná Basin, has a 150 m channel with an average slope of 6.25% (Fontes Júnior, Castro-Santos,Makrakis, Gomes, & Latini, 2012). The average rate of success for passing this section of the fish ladder was reported to be 88% across all migratory species(Makrakis, Miranda, Gomes, Makrakis, & Júnior, 2011).…”

Hydropower Development and Fishways: A Need for Connectivity in Rivers of the Upper Paraná Basin

“…For the most part, fishways with scientific information are a result of partnerships with the hydropower companies and universities which utilize these fishways as a subject of study [44]. This is the case of the fish ladder at Engenheiro Sérgio Motta Hydropower Plant (Porto Primavera, SP), which is the subject of the highest number of published scientific articles [34,38,39,[73][74][75], followed by Itaipu Binacional-Canal da Piracema [41,[80][81][82], Canoas I and II [48,66], but it is also the reality of other fishways in the Tocantins River, Amazon Basin [101][102][103]. Many fishways in South America that have been evaluated are deemed selective or inefficient [41,80,104,105], and despite efficiency problems being commonplace, only two fishways have been modified or reconstructed in an aim to improve their efficiency, as were the cases of the Cachoeira das Emas [71,91] and the Gavião-Peixoto fish ladders [43,95].…”

“…The morphology, physiology, behavior, swimming capacity, and life history of Neotropical species, however, differ from those of temperate regions [14,[37][38][39][40], for which these fish ladders were originally designed. Thus, the non-specificity of fishway projects undertaken in South America have furthered the installation of low-efficiency systems, which have prompted an overall distrust of their functionality [41][42][43]. To make matters worse, few hydroelectric enterprises perform adequate evaluations of attraction and efficiency, as well as the necessary monitoring [44].…”