Composition of functional ecological guilds of the fish fauna of the internal sector of the Amazon Estuary, Pará, Brazil.

Keila R.M Mourão,Flávia Lucena-Frédou,Valdimere Ferreira

doi:10.1590/0001-3765201420130503

Abstract

The present study describes the spatial and temporal structure of the estuarine fish community in the internal sector of the Amazon Estuary. Samples were obtained in the main channels and tidal creeks of Guajará and Marajó Bays and Guamá River. A total of 41,516 fish specimens were collected, representing 136 taxa, 38 families and 12 orders. In the dry season, the mean salinity of the main channel increased along a limnic-marine gradient, between the Guamá River and the Marajó Bay. Species richness was lowest in the mouth of the Guamá River and in the right margin of the Guajará Bay. Fish species composition and environmental guilds differed markedly among areas: Migrants and Freshwater Stragglers were dominant in the Guamá River and the Guajará Bay, while Estuarine, Marine Stragglers and Migrants predominated in the Marajó Bay. However, the trophic guilds were still relatively well balanced, in functional terms. Piscivores and Zoobenthivores were the dominant feeding functional groups in all the studied areas. In this study, the assessment of the community and the use of the guild approach were efficient to describe the structure and functioning of the assemblages of estuarine fish also helping to assess the anthropogenic pressures in the area.

Highlights

In recent studies, the concept of ecological “guilds” has been used to organize information on the function, hierarchical structure, and connectivity of ecological systems, primarily by simplifying relatively complex ecological interactions (Elliott et al 2007, Noble et al 2007, Franco et al 2008a)
Species richness was lowest in the mouth of the Guamá River
The results of the bootstrap analysis suggest that sampling was relatively reliable in all three study areas, with around ninetypercent of the estimated number of species being recorded in all three cases

Summary

Introduction

The concept of ecological “guilds” has been used to organize information on the function, hierarchical structure, and connectivity of ecological systems, primarily by simplifying relatively complex ecological interactions (Elliott et al 2007, Noble et al 2007, Franco et al 2008a). The high socio-economic value of their goods, especially as a source of income and food is well documented (Lambert and Turpie 2003, Glaser and Diele 2004, Ortiz and Wolff 2004, Isaac et al 2009). This environment plays an essential as a feeding and breeding ground, providing appropriate habitats for different stages of the fish life cycle, in addition to functioning as a migratory routes for both anadromous and catadromous species (Yañez-Arancibia 1986, Elliott et al 2007, Martinho et al 2007). Seasonal changes in the composition of the community indicate an influx of freshwater species during the rainy season, while marine species predominate during the dry season, reflecting changes in salinity levels (Camargo and Isaac 2001)

Methods

Results

Conclusion