Efeitos da piscicultura em canais de igarapés sobre a ictiofauna na Amazônia Central

Abstract

The cultivation of fish in channels of igarapés is very common in the rural area of the Amazon region and this work sought to investigate the effects of this creation on the aquatic environments and the ichthyofauna This research was divided in three chapters, where the first describes a theoretical reference about this type of activity and its importance for small fish farmers and their possible consequences that may appear in the environment with the implementation of the crop. In the second chapter, the changes nurseries about fish communities, water quality and substrates were discussed. And in the third chapter we tried to evaluate qualitatively and quantitatively the changes caused by the installation of fish farms in igarapé channels on trophic structure of natural fish communities. The study sites were determined in the municipalities of Novo Airão and Presidente Figueiredo. We selected for each area four igarapés with fish farming and eight igarapés without fish farm. We performed sampling with fish samples, characterization of the igarapés and analysis of the physical and chemical variables of the water and the geoenvironmental characteristics of the igarapés. After sorting and identification of species, these were classified into trophic categories. To analyze the data, we performed indices of diversity, dominance, equitability, principal component analysis (PCA) among the points sampled. Data analyzes were performed between geoenvironmental characteristics, physical and chemical variables of water and trophic categories. Later, we synthesized the data obtained in a Multivariate Permutational Variance Analysis (PERMANOVA), in order to verify the possible effects of the composition of species under the conditions sampled and the environmental variables analyzed. A total of 2302 fish belonging to six (6) orders were collected. The results showed that the data were not sufficient to affirm that the piscicultures of igarapé channels are carrying out some kind of disturbance or environmental alteration in the igarapés studied. The collection sites presented specific and different richness and abundance, trophic categories with no apparent alteration, environmental and limnological characteristics with variations, but these may be associated to the natural conditions of the igarapés.