Avaliação temporal e espacial da comunidade de peixes no canal de fuga da usina hidrelétrica de Três Marias, Rio São Francisco MG

• Ano de defesa: 2011
• Autor(a) principal: Fontes, Raquel Coelho Loures
• Orientador(a): Pompeu, Paulo dos Santos
• Banca de defesa: Madureira, Lauro A. Saint-Pastous, Godinho, Alexandre Lima
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: UNIVERSIDADE FEDERAL DE LAVRAS
• Programa de Pós-Graduação: DBI - Programa de Pós-graduação
• País: BRASIL
• Palavras-chave em Português: Ecossonda; Hidroacústica; Peixe; Jusante; Operação de usina; Echosounder; Hydroacoustic; Fishes; Downstream; Hydropower plant operation
• Área do conhecimento CNPq: CNPQ_NÃO_INFORMADO
• Link de acesso: https://repositorio.ufla.br/handle/1/3209

Hydroelectric power dams cause several environment changes and impacts on the fish communities. Fish, for example, when in the tailwater, can access the draft tube or reach the turbines and be killed. Knowledge of the fish community immediately downstream from dams may help reduce the impacts generated by its operation. This work aimed to study the temporal and spatial variations in the fish community in the Três Marias Hydropower Plant tailwater. The hydroacoustic technique was selected to achieve the main goals, and results were corroborated by the capture of fish with gillnets. Furthermore, we studied the relationship between body size and target strength of Brazilian freshwater fish species. The models of that relationship, presented and validated in this work, can be useful for future studies that aim to estimate fish density and abundance using hydroacoustic, in Neotropical rivers. The results indicated that fish abundance in tailwater was significantly higher in the rainy season (November to March). The species composition also differs between the two seasons. Despite Characiformes be the richest group, Siluriformes were the most abundant. This may explain the greater number of fish detected by the echosounder at night. The evaluation of the information obtained in this work can support management actions, like scheduling operation procedures such as drainage machine during periods of lower abundance in the tailwater (April to October), and reduce the number of turbine's departures from November to March. Furthermore, the density maps together with the area bathymetry may eventually provide information on the best locations for the installation of a fish passage near the dam, if needed in the future. Hydroacoustic can be a useful technique for sampling fish downstream of dams since the interference by bubbles and flow rate is not high enough to prevent detection of the echoes. However, the use of alternative techniques for collecting biological data and identification of fish can corroborate the information obtained by hydroacoustic.