Ecological attributes of fish fauna in the Taquaruçu Reservoir,

Paranapanema River (Upper Paraná, Brazil): composition and spatial distribution

BRITTO¹, S.G. de C. & CARVALHO², E. D.

¹ Environmental Board, Duke Energy International, Brazil. Rodovia Chavantes / Ribeirão Claro, Km 10. Chavantes, SP. CEP 18.970-000.

e-mail: sgbritto@duke-energy.com

² Fish Biology and Ecology Laboratory, Department of Morphology, Institute of Biosciences, UNESP – Campus at Botucatu, SP. Caixa Postal 510. CEP 18618-000 – Botucatu – SP.

e-mail: carvalho@ibb.unesp.br

 ABSTRACT: Construction of dams leads to several environmental alterations on flora and fauna specially on fish. This study determines the composition and spatial organization of fish fauna, in the longitudinal limnological gradient of the Taquaruçu Reservoir, Paranapanema River Basin. Twenty-nine collections were carried out every three months with gill nets in three zones of the gradient. A total of 73 species of fish were captured, among native, transposed and exotic ones. There were differences in the distribution, along the limnological gradient especially between fluvial and lacustrine zones. Greater values of some ecological attributes (species richness, diversity index, abundance and constancy of species) and trophic groups of ichthyofauna were obtained in the fluvial zone. In general, piscivorous and carnivorous are dominant in this reservoir. Different icththyofaunas were found among the zones, and those most influenced by the damming were similar. Comparing our results with other studies on the Paranapanema and Upper Paraná River Basin, it is noted that the ichthyofauna structure along the limnological gradient is a predictive condition of reservoir formation in this basin. Also, the addition of nonnative species is a differential factor in the reorganization of Taquaruçu reservoir, in relation to other reservoirs of the upper stretch of the Paranapanema River basin.

Key-words: Reservoirs, ichthyofauna, ecology, fish, nonnative species.