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Keywords:

  • freshwater;
  • diversity;
  • fish;
  • non-native species;
  • conservation

Abstract

  • 1.
    Lake Encantada, in the basin of the Almada River (Bahia State), has an area of 650.5 ha and a perimeter of 13.3 km. In 1993, an area of 11 800 ha around the lake was designated an Environmental Protection Area (Class V category). The main goal of this study was to identify fish species in the lake and to determine possible threats to their conservation.
  • 2.
    Fish samples were obtained with gillnets between May 2002 and February 2004, and used to calculate indices of species diversity Shannon (H′), richness (d) and evenness (J′).
  • 3.
    Eleven fish species comprising nine families were collected during the sampling period. Three introduced species occurred in the lake: Prochilodus argenteus, endemic to the São Francisco river basin, and two African species, Oreochromis niloticus and Clarias gariepinus. In overall ranking, Prochilodus argenteus was first in number of individuals (46%) and weight (59%), followed by Genidens genidens in numbers (31%), and Clarias gariepinus in weight (15%).
  • 4.
    The occurrence and dominance of introduced species is discussed as well as their possible impacts on the trophic structure of this ecosystem.

Copyright © 2007 John Wiley & Sons, Ltd.