Impactos de piscicultiras em tanques-rede sobre a ictiofauna da represa de Chavantes: dieta, bromatologia e parasitologia
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Data
2011-10-21
Autores
Ramos, Igor Paiva [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Atualmente a implantação de sistemas de pisciculturas em tanques-rede nas represas brasileiras é mais uma forma de impactos negativos sobre a biota e a qualidade da água. Esta atividade atua como fonte de energia secundária ao ecossistema aquático, na forma de sobra de rações e efluentes, que atraem à biota adjacente, causando alterações na estrutura da comunidade local. O objetivo do presente trabalho foi avaliar a influência de pisciculturas em tanques-rede sobre espécies de peixes atraídas para estas áreas, enfocando aspectos biológicos, (dieta, bromatologia e parasitologia) em uma grande represa do médio rio Paranapanema. Para tanto, utilizou-se cinco espécies de peixes (Astyanax altiparanae, Galeocharax knerii, Iheringichthys labrosus, Pimelodus maculatus e Plagioscion squamosissimus). Exemplares destas espécies foram capturados com auxílio de redes de espera, em áreas próximas as pisciculturas em tanques-rede (TR) e em áreas sem a influência deste tipo de atividade (CT). Foi caracterizada a dieta para as cinco espécies selecionadas, composição bromatológica das espécies G. knerii e P. maculatus e avaliada a taxa de infecção de metacercárias de Austrodiplostomum compactum em P. squamosissimus, sendo todas as análises comparativas entre as áreas TR e CT. Os resultados demonstram que houve grandes alterações na dieta das espécies generalistas tróficas (A. altiparanae, P. maculatus e I. labrosus) com consequente aumento nos valores de fator de condição de tais espécies nas áreas TR. Espécies especialistas tróficas como peixes carnívoros G. knerii e P. squamosissimus apresentaram pequenas diferenças entre as áreas TR e CT referente à dieta, não apresentando alterações para demais análises. Quanto à análise bromatológica, foram observados valores significantemente superiores (p < 0,05) para extrato etéreo (lipídeos totais)...
Currently, the deployment of fish farming in cages in Brazilian reservoirs is a source of negative impacts on water quality and biota. This activity acts as a secondary source of energy to the aquatic ecosystem, such as ration wastes that attract adjacent biota, causing changes in the structure of local community. The aim of this study was to evaluate the influence of fish farming in cages on fish species attracted to these areas, focusing on biological features (diet, bromatology and parasitology) in a large dam in the middle Paranapanema River. To this aim, it was used five fish species (Astyanax altiparanae, Galeocharax knerii, Iheringichthys labrosus, Pimelodus maculatus and Plagioscion squamosissimus). The specimens were captured with gill nets in areas around the cages (CF) and in areas without the influence of this type of activity (CT). It was characterized the diet for the five selected species, bromatological composition of the species G. knerii and P. maculatus, and the infection rate of metacercariae of Austrodiplostomum compactum in P. squamosissimus was assessed, being all comparative analysis between the CF and CT areas. The results show that there were significant changes in the diet of trophic generalist species (A. altiparanae, P. maculatus and I. labrosus) with consequent increase in condition factor values in the TR areas. Trophic specialist species, such as the carnivorous fish G. knerii and P. squamosissimus, showed small differences between CF and CT areas regarding diet, with no significant changes for other analyses performed. Concerning bromatological analysis, significantly higher values were observed (p <0.05) for lipids (total lipids) in the tank area, while gross protein and water showed higher values in the control area, and contents of ash did not differ (p> 0.05) for P. maculatus. There were no differences (p> 0.05) between... (Complete abstract click electronic access below)
Currently, the deployment of fish farming in cages in Brazilian reservoirs is a source of negative impacts on water quality and biota. This activity acts as a secondary source of energy to the aquatic ecosystem, such as ration wastes that attract adjacent biota, causing changes in the structure of local community. The aim of this study was to evaluate the influence of fish farming in cages on fish species attracted to these areas, focusing on biological features (diet, bromatology and parasitology) in a large dam in the middle Paranapanema River. To this aim, it was used five fish species (Astyanax altiparanae, Galeocharax knerii, Iheringichthys labrosus, Pimelodus maculatus and Plagioscion squamosissimus). The specimens were captured with gill nets in areas around the cages (CF) and in areas without the influence of this type of activity (CT). It was characterized the diet for the five selected species, bromatological composition of the species G. knerii and P. maculatus, and the infection rate of metacercariae of Austrodiplostomum compactum in P. squamosissimus was assessed, being all comparative analysis between the CF and CT areas. The results show that there were significant changes in the diet of trophic generalist species (A. altiparanae, P. maculatus and I. labrosus) with consequent increase in condition factor values in the TR areas. Trophic specialist species, such as the carnivorous fish G. knerii and P. squamosissimus, showed small differences between CF and CT areas regarding diet, with no significant changes for other analyses performed. Concerning bromatological analysis, significantly higher values were observed (p <0.05) for lipids (total lipids) in the tank area, while gross protein and water showed higher values in the control area, and contents of ash did not differ (p> 0.05) for P. maculatus. There were no differences (p> 0.05) between... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Ictiologia, Peixe - Criação, Alimentos - Analise, Paranapanema, Rio, Bacia (SP e PR), Cage farms, Ichthyofauna, Bromatology
Como citar
RAMOS, Igor Paiva. Impactos de piscicultiras em tanques-rede sobre a ictiofauna da represa de Chavantes: dieta, bromatologia e parasitologia. 2011. 68 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2011.