Composição e alimentação da ictiofauna da área de influência da Usina Hidrelétrica de Funil, localizada no rio Grande, região sul do estado de Minas Gerais
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Data
2008-05-21
Autores
Souza-Hojo, Débora Matioli [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O presente estudo foi desenvolvido no curso superior do rio Grande, bacia do alto rio Paraná, na área de influência da Usina Hidrelétrica de Funil, localizada na região sul de Minas Gerais, com o objetivo principal de verificar a composição e alimentação da ictiofauna. Para isto, foram analisados os seguintes parâmetros: distribuição de classes de comprimento, diversidade ( e ) entre os pontos de coleta, relação peso- comprimento e fator de condição, alimentação e elaboração do espectro alimentar por ponto. As coletas ocorreram no período de julho de 2005 a julho de 2006, com freqüência trimestral, sendo amostrados 19 pontos, distribuídos a jusante e a montante da hidrelétrica, incluindo lagoas marginais sazonalmente alagadas e tributários de montante. Os petrechos de pesca utilizados consistiram de rede de espera e tarrafas de malhas variadas, anzol, rede de arrasto e peneira. Foram capturados 4.035 exemplares pertencentes a 32 espécies, abrangendo 5 ordens e 11 famílias. A distribuição das classes de comprimento revelou o predomínio de espécies de pequeno e médio porte. Em r elação à diversidade , os pontos de coleta mais representativos em número de espécies foram os de jusante e montante-reservatório e, em relação à diversidade , a combinação jusante versus montante-reservatório dentre as demais, foi a que apresentou maiores valores para os índices de similaridade. As variações na condição corporal apresentadas pelas espécies for am associadas, principalmente, com a atividade alimentar. Foram analisados 757 estômagos provenientes de 26 espécies, correspondendo a 81,25% do total de espécies capturadas. De forma geral, os itens mais consumidos pelos peixes foram vegetal superior, insetos terrestres (com predominância das ordens Hymenoptera e Coleoptera), sedimento e, em especial,...
This study was taken at the superior course of Grande river, upper Paraná river basin, at Funil Hydroelectric Power Plant area, in southern region of Minas Gerais state, with the main aim of analyzing the composition e feeding habits of the ictiofauna. Due to this, some parameters were analyzed: size classes distribution, diversity (a e ß) between sampling sites, weight/size r elation and condition factor, feeding habits and food spectrum registered per species for each sampling site. Collections were conducted from july 2005 to july 2006, in a quarterly frequency. Nineteen sites were sampled, distributed upstream and downstream from the power plant, including seasonal floodplain lakes and upstream tributaries. To captur e fishes, several sizes of gillnets and casting nets, fishhook, trawling net and sieve, were used. 4.035 individuals of 32 species, in 5 orders and 11 families, were captured. Size class distribution showed a small/medium size predominance. The most representative sites in number of species for a diversity, and the two most similar sites for ß diversity, were downstream and reservoir. Variations in corporal conditions were associated basically with feeding activity. 757 stomachs from 26 species were analyzed, corresponding 81,25% of the total captured species. In general, most consumed items were upper vegetal, terrestrials insects (mainly of Hymenoptera and Coleoptera orders), sediment and immature fases insects. The last ones mainly among fishes collected at the floodplain lakes. Throughout food spectrum analysis for each species and sites, herbivory, piscivory, omnivory and ileophagous diet were determined. Although, most species analyzed were classified as omnivorous, revealing a generalistic behaviour and feeding plasticity.
This study was taken at the superior course of Grande river, upper Paraná river basin, at Funil Hydroelectric Power Plant area, in southern region of Minas Gerais state, with the main aim of analyzing the composition e feeding habits of the ictiofauna. Due to this, some parameters were analyzed: size classes distribution, diversity (a e ß) between sampling sites, weight/size r elation and condition factor, feeding habits and food spectrum registered per species for each sampling site. Collections were conducted from july 2005 to july 2006, in a quarterly frequency. Nineteen sites were sampled, distributed upstream and downstream from the power plant, including seasonal floodplain lakes and upstream tributaries. To captur e fishes, several sizes of gillnets and casting nets, fishhook, trawling net and sieve, were used. 4.035 individuals of 32 species, in 5 orders and 11 families, were captured. Size class distribution showed a small/medium size predominance. The most representative sites in number of species for a diversity, and the two most similar sites for ß diversity, were downstream and reservoir. Variations in corporal conditions were associated basically with feeding activity. 757 stomachs from 26 species were analyzed, corresponding 81,25% of the total captured species. In general, most consumed items were upper vegetal, terrestrials insects (mainly of Hymenoptera and Coleoptera orders), sediment and immature fases insects. The last ones mainly among fishes collected at the floodplain lakes. Throughout food spectrum analysis for each species and sites, herbivory, piscivory, omnivory and ileophagous diet were determined. Although, most species analyzed were classified as omnivorous, revealing a generalistic behaviour and feeding plasticity.
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Palavras-chave
Usinas hidrelétricas, Ictiofauna
Como citar
SOUZA-HOJO, Débora Matioli. Composição e alimentação da ictiofauna da área de influência da Usina Hidrelétrica de Funil, localizada no rio Grande, região sul do estado de Minas Gerais. 2008. vii, 98 f. Dissertação (mestrado) - Universidade Estadual Paulista, Centro de Aqüicultura, 2008.