Population structure and natural diet of Astyanax cf. paranae Eigenmann 1914 a typical species of neotropical headwaters streams

This work describes the habits of individuals of the species Astyanax cf. paranaethat inhabitRibeirão do Ferro,a bedside stream. Overall,92 specimens were analyzed (53 females and 39 males),and the size ranged from class 4.7-5.7 cm to class 10.7-11.7 cm. The females consisted in thelarger portion of the samples,except for classes of 4.7-5.7 and 5.7-6.7 cm. The condition factor between males and females (t = 2.1545; p < 0.05) shows distinguished values,with females having higher averages. Fragments of allochthonous insects and plant matter make up the basis of the species' diet. The study showed that the population of A. cf. paranaeis predominantly females and have the highest standard for length and weight,which may favor biological diversity and increased larvae and juveniles,maximizing the chance of individuals reaching adulthood. The species prefers an environment with predominance of rocks and logs,which favors shelters. Its diet comes mostly from the riparian forest,with a high dependence on the allochthonous items, thus, these vegetations are very important for maintaining populations of the species.

A multiple hypothesis approach to explain species richness patterns in neotropical stream-dweller fish communities.

Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hypotheses can be useful to explain for these purposes. Therefore, we used a selection model approach to assess the predictive capacity of such hypotheses, and to determine which of them (combined or not) would be the most appropriate to explain the fish species distribution in small Brazilian streams. We perform the Akaike's information criteria for models selections and the eigenvector analysis to control the special autocorrelation. The spatial structure was equal to 0.453, Moran's I, and require 11 spatial filters. All models were significant and had adjustments ranging from 0.370 to 0.416 with strong spatial component (ranging from 0.226 to 0.369) and low adjustments for environmental data (ranging from 0.001 to 0.119) We obtained two groups of hypothesis are able to explain the richness pattern (1) water-energy, temporal productivity-heterogeneity (AIC = 4498.800) and (2) water-energy, temporal productivity-heterogeneity and area (AIC = 4500.400). We conclude that the fish richness patterns in small Brazilian streams are better explained by a combination of Water-Energy + Productivity + Temporal Heterogeneity hypotheses and not by just one.

Composição ictiofaunística do Rio Turvo, Pilar do Sul, São Paulo, Brasil / Icthyofaunistic composition of the Rio Turvo, Pilar do Sul, São Paulo, Brazil

Objetivo ­ Realizar um inventário das espécies de peixes do rio Pilar do Sul, considerando ainda aspectos da sua comunidade como riqueza e diversidade de espécies. Métodos ­ Peixes foram coletados durante as épocas chuvosa e seca de 2004, em doze locais de amostragem situados nos trechos alto, médio e inferior do rio. Resultados ­ A assembleia de peixes se mostrou rica em espécies, com 18 espécies registradas, pertencentes a 13 gêneros, 7 famílias e às ordens Characiformes (15 spp.); Siluriformes (3 spp.). A fauna de peixes foi composta por espécies de pequeno porte (<200 mm CP) e por indivíduos de espécies que atingem porte médio (até 400 mm CP) e grande (mais de 400 mm CP). Conclusões ­ O rio Turvo, assim como outros ambientes lóticos de transição entre riachos e grandes rios na drenagem do Alto Rio Paranapanema são considerados importantes para a conservação da ictiofauna porque apresentam habitats disponíveis para populações persistentes de espécies de pequeno porte e para indivíduos ou cardumes não persistentes de espécies de médio e grande porte, que podem ocupar outros habitats (por exemplo, as lagoas marginais, as planícies de inundação e as calhas principais de grandes rios). Esta importância para conservação também é ressaltada quando se leva em consideração os inúmeros impactos levantados pelo presente estudo como extração de areia, assoreamento, degradação da vegetação ripária e lançamento de esgoto

Objective ­ To perform the inventory the fish species of turvo river, further considering aspects your community of richness species diversity. Methods ­ Fish were collected during the rainy and dry seasons in 2004 in 12 sampling sites located in the upper, middle and lower stretches of the river. Results ­ The fish assemblage was rich, with 18 recorded species belonging to 13 genera, 7 families and the orders Characiformes (15 spp.) and Siluriformes (3 spp.). The fish fauna was composed of small-sized species (<200 mm SL) and individuals of species that reach medium (up to 400 mm SL) and large (more than 400 mm SL) sizes. Conclusions ­ Turvo river is similar to other lotic environments that provide a transition between streams and large rivers in the catchment of the Upper Paranapanema River. They are considered important for the conservation of the ichthyofauna because of their habitats that are available for persistent populations of small species and non-persistent individuals or schools of medium and large species, which can occupy other habitats (e.g. marginal lakes, flood plains and main river channels). This importance for conservation is also highlighted when one takes into account the numerous impacts raised by this study, such as sand mining, siltation, degradation of riparian vegetation and discharge of waste.

Fish fauna of Floresta Nacional de Ipanema, Sao Paulo State, Brazil

The Floresta Nacional de Ipanema is located on the southeast of the state of São Paulo, Brazil, and belongs to the cities of Araçoiaba da Serra, Iperó and Capela do Alto. It extends over an area of 5,069 ha surrounded by several streams, small lakes, the Ipanema river and the Hedberg dam. The fish species in this area were sampled between 1993 and 2012 in several isolated studies, with the use of gill nets and sieves. Fifty species of fish were registered, 43 native and 7 non-native (Cyprinus carpio, Piaractus mesopotamicus, Brycon cephalus, Triportheus nematurus, Clarias gariepinus, Tilapia rendalli and Poecilia vivipara), distributed in seven Orders, 21 Families and 41 Genera. The present study aimed at cataloguing the fish species in the Ipanema National Forest. Handling and preservation actions will be based on the information obtained.

A Floresta Nacional de Ipanema está localizada no sudoeste do estado de São Paulo, Brasil e pertence às cidades de Araçoiaba da Serra, Iperó e Capela do Alto. Estende-se por uma área de 5, 069 ha, onde ocorrem diversos riachos, pequenos lagos, o rio Ipanema e a represa de Hedberg. As espécies de peixes dessa unidade de conservação foram amostradas entre 1993 e 2012 em vários estudos realizados, com o uso de redes de espera e peneiras. Foram registradas 50 espécies de peixes, 43 nativas e 7 não-nativas (Cyprinus carpio, Piaractus mesopotamicus, Brycon cephalus, Triportheus nematurus, Clarias gariepinus, Tilapia rendalli e Poecilia vivipara), distribuídas em sete ordens, 21 famílias e 41 gêneros. O estudo teve como objetivo catalogar as espécies de peixes da Floresta Nacional de Ipanema. Ações de manejo e preservação deverão ser baseadas nas informações obtidas.

Utilização de macroinvertebrados bentônicos no biomonitoramento de atividades antrópicas na bacia de drenagem do Reservatório de Itupararanga, Votorantim - SP, Brasil / Using benthic macroinvertebrates for biomonitoring the anthropic activity in the drainage basin of Itupararanga reservoir, Votorantim - SP, Brazil

Objetivo - A Represa de Itupararanga é a principal fonte de abastecimento de água da região de Sorocaba, banhando os municípios de Ibiúna, Piedade, São Roque, Cotia, Vargem Grande Paulista, Mairinque, Alumínio e Votorantim, no Estado de São Paulo. O trabalho tem como objetivo avaliar a diversidade de macroinvertebrados bentônicos abordando as relações de parâmetros bióticos e abióticos em diferentes pontos da bacia de drenagem da Represa de Itupararanga. Métodos - Realizou-se quatro coletas no período de setembro de 2008 a abril de 2009, cada uma com 5 pontos amostrais, dos quais dois foram lagoas marginais à represa, um riacho, um ponto na Represa de Itupararanga e um ponto na Cachoeira da Chave. Os macroinvertebrados bentônicos foram coletados com ajuda do aparelho amostral "Surber" sendo triados e identificados no Laboratório de Ciências Biológicas da Universidade Paulista, campus Sorocaba. Resultados - No inventárioforam encontradas 22 taxas, sendo 5 famílias de Diptera, 1 família de Megaloptera, 5 famílias de Odonata, 3 famílias de Coleoptera, 5 famílias de Hemiptera e 3 famílias de Ephemeroptera. Houve predominância de Chironomidae (Diptera) com 68,6% dos organismos, seguidos de Pleidae (Hemiptera) com 7,14% dos organismos e Libellulidae (Odonata) com 4,48% dos organismos coletados. Os pontos com valores mais altos no índice de diversidade de Shannon-Wiener foram as lagoas marginais que coincidiram com valores mais baixos de condutividade e sólidos totais dissolvidos. Conclusão - Analisando a bacia através do índice biótico BMWP, concluiu-se que encontra-se em estado aceitável, com algumas evidências de contaminação.

Objective - The Itupararanga reservoir is the main supply source of potable water for the Sorocaba region, in the state of São Paulo, Brazil, and it supplies the municipalities of Ibiúna, Piedade, São Roque, Cotia, Vargem Grande Paulista, Mairinque, Alumínio and Votorantim. The purpose of this study was to analyze the diversity of benthic macroinvertebrates, including the relationships between biotic and abiotic parameters, at different points around the drainage basin of the Itupararanga reservoir. Methods - Four sets of samples were taken over the period between September 2008 and April 2009, with each set consisting of following 5 sampling points: two from the lakes adjacent to the reservoir, one from a nearby stream, one from a point in the Itupararanga reservoir and one from the local Chave Waterfall. The benthic macroinvertebrates were collected with the aid of a "Surber" sampling apparatus, and they were subsequently triaged and identified in the Laboratory of Biological Sciences of Sorocaba, campus of the University Paulista. Results - We found 22 taxa were found in the species inventory present in the samples, including 5 families of Diptera, 1 family of Megaloptera, 5 families of Odonata, 3 families of Coleoptera,5 families of Hemiptera and 3 families of Ephemeroptera. There was a predominance of Chironomidae (Diptera), accounting for 68.6% ofthe organisms, followed by Pleidae (Hemiptera) and Libellulidae (Odonata), which accounted for 7.14% and 4.48% of the organisms collected, respectively. The sampling locations with the highest values in the Shannon-Wiener diversity index were the adjacent lakes, which were also the locations with the lowest values for conductivity and total dissolved solids. Conclusion - Upon analyzing the basin with the BMWP biotic index, we concluded that its overall condition is acceptable, although there is some evidence of contamination.

Spatial and temporal patterns and their influence on fish community at Itupararanga Reservoir, Brazil.

The Itupararanga Reservoir is located at the Sorocaba River Basin, São Paulo State, Brazil. Five cities use the waters of this reservoir for human consumption. Despite this intensive use of the water resource, no study has been undertaken on the ichthyofauna of this reservoir. Collections were performed in nine sampling stations, where each three were located in the riverine, transitional and lacustrine zones. Fish specimens were collected using eight monofilament gillnets of 10 m length each, with varied mesh sizes, in the rainy and dry seasons, which corresponded to our spatial scale of analysis. Overall, 14 species of fish were identified, with the highest contribution from Characidae and Curimatidae. The most abundant species were: the "lambari", Astyanax fasciatus, the "saguiru", Cyphocharax modestus, the "lambari bocarra", Oligosarcus paranaensis, and the "mandi", Iheringichthys labrosus. Diversity tended to be higher during the dry season, although the difference was not statistically significant. Cluster analysis identified four season sampling groups differentiated by within-season distribution of species. Mantel's test showed that this distribution was little affected by environmental factors, suggesting that biotic factors were more important in determining the species distribution within the reservoir.

The fish fauna in tropical rivers: the case of the Sorocaba River basin, São Paulo, Brazil

A survey was carried out on the fish species in the Sorocaba River basin, the main tributary of the left margin of the Tietê River, located in the State of São Paulo, Brazil. The species were collected with gill nets. After identification of the specimens, their relative abundance, weight and standard length were determined. Up to the present moment there are not any studies that focus this subject in this hydrographic basin. Fifty-three species, distributed in eighteen families and six orders were collected. Characiformes were represented by twenty-eight species, Siluriformes by seventeen species, the Gymnotiformes by three species, Perciformes and Cyprinodontiformes by two species, and the Synbranchiformes by one species. Among the collected species there were two exotic. The most abundant species were Astyanax fasciatus and Hypostomus ancistroides. In relation to total weight the most representative species were Hoplias malabaricus and Hypostomus ancistroides. Cyprinus carpio, Prochilodus lineatus, Schizodon nasutus and Hoplias malabaricus were the most representative species in relation to average weight. Largest standard length were recorded for Sternopygus.

The fish fauna in tropical rivers: the case of the Sorocaba River basin, São Paulo, Brazil.

A survey was carried out on the fish species in the Sorocaba River basin, the main tributary of the left margin of the Tietê River, located in the State of São Paulo, Brazil. The species were collected with gill nets. After identification of the specimens, their relative abundance, weight and standard length were determined. Up to the present moment there are not any studies that focus this subject in this hydrographic basin. Fifty-three species, distributed in eighteen families and six orders were collected. Characiformes were represented by twenty-eight species, Siluriformes by seventeen species, the Gymnotiformes by three species, Perciformes and Cyprinodontiformes by two species, and the Synbranchiformes by one species. Among the collected species there were two exotic. The most abundant species were Astyanax fasciatus and Hypostomus ancistroides. In relation to total weight the most representative species were Hoplias malabaricus and Hypostomus ancistroides. Cyprinus carpio, Prochilodus lineatus, Schizodon nasutus and Hoplias malabaricus were the most representative species in relation to average weight. Largest standard length were recorded for Sternopygus macrurus, Steindachnerina insculpta, Eigenmannia aff. virescens and Cyprinus carpio.