Body condition and energy density of juvenile streaked Prochilod prochilodus lineatus (Valenciennes, 1837) in a neotropical floodplain

Abstract

Variations in energetic density (ED) and the relative condition factor (Kn) of juveniles of Prochilodus lineatus were investigated to identify whether these two variables respond similarly to environmental factors. We hypothesized that fluviometric levels in different sub-basins of the Upper Paraná River floodplain positively influence the ED and Kn of juvenile fish. Temporally, the values of ED and Kn were linked more directly to the dynamics of the flood pulses on the plain. Spatially, the lowest values of ED and Kn were observed in the environment that was directly affected by the operation of dams, the sub-basin Paraná. Although the energy density and condition factor did not show similar results for juveniles in some of the analyses, the evaluation of both parameters provided a complementary tool and additional information that enabled a more accurate investigation of the temporal and spatial dynamic processes in this Neotropical floodplain. We conclude that water level variations in different sub-basins of the Upper Paraná River floodplain considerably affect the relative condition factor and energy status of P. lineatus. We suggest that the impacts of this modification should be mitigated or avoided in order to maintain fish stocks and promote ecosystem integrity.