Composition and spatial distribuition of fish species in Rio de Contas Streams, Bahia State, Brazil

• Grant number: 12/05850-0
• Support type: Regular Research Grants
• Duration: June 01, 2012 - May 31, 2014
• Field of knowledge: Biological Sciences - Zoology - Applied Zoology
• Principal researcher: Roberto Goitein
• Grantee: Roberto Goitein
• Home Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

The purpose of this study is to know the fish fauna composition of small streams, which compose the Contas river basin and to verify the existence of a spatial distribution pattern of these species at these distinct water courses. Four trimestral collecting excursions will be performed using mainly electrical fishing devices, at the tree basin compartments, as follows: a) Contas river above the confluence with the Gavião river; b) Gavião river drainage; c) Gongogi river drainage, in this way obtaining information about the higher altitude fish fauna, also those living at the depression of the Contas river and those living at the domain of the Atlantic forest, respectively. In addition, each sampling site is going to be characterized by the observation of its physiographic structure, by observing its physical-chemical parameters and also the external aspects, such as the surrounding vegetation. Morphological measurements to be obtained will permit the calculation of a set of ecomorphological indexes with which to classify the species in relation to feeding habits or to the resources to be potentially exploited by them. For each sampling place some ecological descriptors will be calculated, as follows: species richness and diversity. The sampling points will be ordinated in relation to the species composition by using the Non-metric Multidimensional Scaling (NMDS) from a similarity Jaccard matrix. In order to ordinate the sampling points, according to abiotic features presented by these points, the same analysis will be used, but in this case using a Bray Curtis distance matrix. Finally, a Canonical Correlation Analysis (CCA) will be employed in order to verify the existence of correlation between the species composition and the abiotic variables for each sampling place. The verification of the compartment structuration hypothesis in function of such possible distinctions within the basin will be analyzed by using the similarity analysis (ANOSIM), establishing a start point calculated by the Jaccard Index distance matrix for the qualitative approach and with a distance matrix calculated by the Morisita-Horn Index for the quantitative approach. (AU)