The ichtlyogical fauna of the Amazonian River Systems offers high flexibility, which in your
time trophic, is associated with the dynamics of these systems. However, with the
construction of hydroelectric power stations, this dynamic has been threatened. The objective
of this study was to characterize and verify possible differences in the diet of four fish species
from the downstream, upstream/reservoir and upstream/transition stretches of the Curuá-Una
Hydroelectric Plant, as well as to estimate the weight-length and factor condition. For this, the
collections were carried out in the months of november 2016 and march and november of
2017, with gill nets, with different mesh sizes. The species selected for this study were:
Serrasalmus rhombeus, Hemiodus microlepis, Auchenipterus nuchalis and Curimata knerii
and from these biometric data of length and weight were obtained and the stomach was
collected for analysis. The analysis of the diet was carried out using the frequency of
occurrence and volumetric methods, combined with the Index of Food Importance-IAi. The
weight-length ratio estimated for the different species was allometric type positive (S.
rhombeus), allometric negative (H. microlepis and C. knerii) and isometric (A. nuchalis). The
diet of the above species did not present significant differences (PERMANOVA) (F = 0,523;
p> 0,05), remaining piscivora (S. rhombeus), detritivorous (H. microlepis and C. knerii) and
insectivorous (A. nuchalis), independent of the studied sections. On the other hand, the
condition factor was significantly different (Kruskal - Wallis) for S. rhombeus species (Hc:
2,08; p <0,05), H. microlepis (Hc: 47; p <0,05 ), and C. knerii (Hc: 23,84; p <0,05), among
the different stretches, however, for A. nuchalis (Hc: 0,46; p> 0,05), no differences , it was
possible to conclude that the trophic ecology of the four species was the same along the
stretches in the area of influence of the Curuá-Una UHE and the growth is within the limits
established by Froese (2006), while the condition factor varied differently between the
stretches for each species.
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