Lack of Information Hides the Impact of Human Activities in Estuarine Fish From Southern of Brazil

Abstract

Brazilian coast are sites of significant chemical discharge impacting the estuaries, natural "nursery" of aquatic organisms. In order to investigate the human impact in Lagoa dos Patos-South of Brazil-gills and liver of croakers Micropogonias furnieri were used as morphological biomarkers. Forty individuals from reference and polluted sites were caught in winter and summer of 2003. The individuals were measured, weighted and liver and gills samples were processed for light and transmission and scanning electron microscopy. Individuals from the polluted area (winter) showed strong morphological evidences of chemical exposure. The observed ultrastructure lesions and alterations confirmed the worst conditions of individuals from polluted site mainly in winter. The sediment remobilization due to rainfall may be the cause of chemical bioavailability. Further chemical studies are necessary in Lagoa dos Patos as the risk of exposure to biota and human populations was demonstrated.