The role of riverine forests for food supply for the omnivorous fish Brycon opalinus Cuvier, 1819 (Characidae) in the Serra do Mar, Southeast Brazil

Lm Gomiero,Fms Braga,Ag Manzatto

doi:10.1590/s1519-69842008000200013

Lm Gomiero, Fms Braga + Show 1 more

Open Access

https://doi.org/10.1590/s1519-69842008000200013

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Abstract

The purpose of this study was to characterize the diet of the fish Brycon opalinus (Characidae) seasonally and locally, allowing for the determination of its food items and trophic relations with the aquatic and terrestrial environments. The study area encompasses three rivers (Paraibuna, Ipiranga and Grande) in the basin of the Paraibuna, southeast Brazil. Twelve monthly collections were made from January to December 2004. The degree of stomachic repletion and of accumulated visceral fat was analyzed, as was the intestinal length in each class of total length. The frequency of occurrence and the degree of food preference (DFP) of the food items of Brycon opalinus were determined by separating the vegetal and animal items, autochthonous and allochthonous, by insect order and vegetal family consumed. The frequency of occurrence of items of animal origin was found to be equivalent to that of vegetal origin, thus characterizing the omnivorism of Brycon opalinus feeding.

Highlights

The riparian zone occurs at the interface between aquatic and terrestrial ecosystems and regulates the transfer of energy between these systems, as well as insolation in the aquatic system (Pusey and Arthington, 2003)
The frequency of occurrence of the food items was determined based on an analysis of the 256 stomachic and intestinal contents of Brycon opalinus
For Brycon cephalus (Günther, 1869) in Amazonia, replete stomachs were found to be frequent during the different seasons of the year and accumulated fat was the norm throughout the year except during reproduction

Summary

Introduction

The riparian zone occurs at the interface between aquatic and terrestrial ecosystems and regulates the transfer of energy between these systems, as well as insolation in the aquatic system (Pusey and Arthington, 2003). These sites shelter a wide diversity and density of invertebrates when compared to the adjacent forests and comprise some of the earth’s most productive ecosystems. The terrestrial matter carried into the water supplies an important food resource for fishes; the riparian integrity is extremely important for the survival of these species (Pusey and Arthington, 2003; Melo et al, 2004). Anthropic activities have put freshwater fishes, from the smallest streams to the largest rivers, under profound and

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