A utilização das descargas dos órgãos elétricos de Apteronotus hasemani e Apteronotus bonapartii (Apteronotidae Gymnotiformes) como bioindicadores em ambientes aquáticos

Abstract

Electric fishes are well known for their conspicuous ability to generate and to detect electric fields, called electrogenisis and electroreception. The integrated electrogenic and electrosensory system of the Neotropical Gymnotiform fishes serves two purposes:communication, and active electrolocation. In this dissertation I suggest an alternative for environmental monitoring using information about biophysical characters of the electric organ discharges (E.O.D.) of the Amazonian electric knifefishes: Apteronotus hasemani and Apteronotus bonapartii. The principle is established on the time characterization of the electric signal emitted by the fish and is based in the fact that the E.O.D frequency and waveform, vary as a function of physico-chemical characteristics in aquatic environment. In the first chapter I describe the way that we follow to select the species. In the second chapter I establish the normal pattern discharges, based on the E.O.D temporal stability of both species. In chapter 3, this study evaluates the effects of pH, a variable that naturally change in Amazon environments and can cause directly influence on the electric activity of those species. In chapter 4 I test the effect of a secondary product associated to petroleum exploration, água de formação, in A. hasemani E.O.D. Because E.O.D plays a role in social interactions, changes induced by these chemicals could influence fish behavior and survival. These results will be used to contribute in development of a real time biomonitoring system to aquatic environments.