Estrutura e composição da ictiofauna de riachos da bacia do Rio Grande no estado de São Paulo, sudeste do Brasil
Keywords:Upper Rio Paraná basin, Rio Grande, Rio Turvo, Rio Pardo, Rio Sapucaí, stream fishes, diversity, southeastern Brazil
AbstractEach stream stretch had its midpoint located with a GPS satellite receiver and had its fish fauna sampled via a standardized environmental data and fish collection methodology (primarily utilizing electrofishing) with the aim of providing the following information about each stream: 1) the taxonomic composition of the fish fauna and the contribution of each species in that stream in terms of both number of individuals and biomass; 2) a photographic documentation of the live coloration of representative specimens of each collected species; and 3) the description of each sampled environment, with colored photographic illustrations and details of the main biotic and abiotic parameters. Overall 3,070 fishes were collected, belonging to six orders, 18 families, 44 genera, and 64 species, with a total biomass of 14.3 kg. Of the collected species, approximately 50% were Characiformes, 26.5% Siluriformes, 11% Perciformes, 6% Gymnotiformes, 5% Cyprinodontiformes, and 1.5% Synbranchiformes. The most abundant species in terms of total number of individuals were Astyanax altiparanae (17.4%) and Hypostomus ancistroides (9%); the species with the largest biomasses were Astyanax altiparanae (35%) and Geophagus brasiliensis (9%). In terms of abundance and biomass collected for each family, the Characidae was clearly the predominant family followed by the Loricariidae, and Cichlidae. Among the sampled stream stretches, locality SG6 with 26 species and locality PG4 with three species yielded the highest and lowest richness in terms of species numbers, respectively. This coincides with the values obtained for the Shannon-Wiener index of specific diversity (H' = 1.08 and 0.26, respectively). The median species richness for all streams stretches was 12. In the species richness estimate by extrapolation for all 18 sampled stream stretches, a value of 93 species was obtained (with a standard error of three) indicating the need for an additional moderate sampling effort to reach the asymptote of the curve. Of the 64 collected species, four (approximately 6% of the total) are clearly new to science and seven other species (approximately 11% of the total) are of indefinite taxonomic status and require further analysis. Two of the captured species are certainly introduced (approximately 3% of the total). Analysis of the trophic and spatial structure of the studied fish fauna indicates that the 10 numerically dominant species in the sampled streams can be grouped, based on published data, into five guilds that are in decreasing order of numeric importance: nektonic omnivores; benthic invertivores; periphytovores; algivores and benthic omnivores. An identification key for all the species of fish collected during this study is provided.
How to Cite
Castro, R. M. C., Casatti, L., Santos, H. F., Melo, A. L. A., Martins, L. S. F., Ferreira, K. M., Gibran, F. Z., Benine, R. C., Carvalho, M., Ribeiro, A. C., Abreu, T. X., Bockmann, F. A., Pelição, G. Z., Stopiglia, R., & Langeani, F. (2004). Estrutura e composição da ictiofauna de riachos da bacia do Rio Grande no estado de São Paulo, sudeste do Brasil. Biota Neotropica, 4(1). Retrieved from //www.biotaneotropica.org.br/BN/article/view/1111