Influência de processos locais e regionais nas assembléias de peixes em reservatórios do Estado do Paraná, Brasil

Abstract

The aim of this study was to identify the main processes (local and/or regional) that influence in the composition and structure of fish assemblages in reservoirs located in the state of Paraná. Six reservoirs were sampled (Capivari, Guaricana, Alagados, Fiú, Mourão and Rio dos Patos). The samples were quarterly taken from July/95 to February/97 and March/98 to February/99 using gillnets and trammel nets of different mesh sizes set for 24 hours. The abundance was indexed by the catch per effort in number (No. ind./ 1000m2 net* 24 hs). All fishes collected were identified, measured and weighted. Some abiotic variables (local process) were measured during the samples. The detrended correspondence analysis (DCA) and the principal components analysis (PCA) were applied to summarize abundance data and abiotic variables, respectively. The scores of the axis retained for interpretation in both analyses were used to assess the relation between abiotic variables (local and regional) and fish assemblage structure. The regional processes appeared to exert strong influence on the composition and, consequently, on the structure in the reservoirs of fish assemblage.