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 off. virescens and Cyprinus carpio.

Effects of nitrate concentration on larval development of the giant river prawn, Macrobrachium rosenbergii

The effect of nitrate concentration on giant river prawn, Macrobrachium rosenbergii, larvae was investigated. Survival rate, weight gain, and larval development were evaluated for different concentrations of nitrate in three experiments. The experiments were divided i n to two phases. In the first phase, larvae from stages I through VIII were analysed, while in the second phase larvae from stage VIII through post-larvae metamorphosis were analysed. Oxygen consumption was also determined for zoea I, II, and VIII exposed to 0, 700, and 1,000 mg/L of nitrate-N. No effect was observed for concentrations up to 180 mg/L NO3-N (experiments I and II), and nitrate levels as 1,000 mg/L NO3-N did not affect survival in the first phase of the third experiment. On the other hand, larval stage index (LSI) and weight gain decreased as nitrate-N concentration increased from 0 to 1,000 mg/L. In the second phase, survival and metamorphosis rate decreased as nitrate concentration increased, according to a linear model. The effect of nitrate levels on weight gain followed a curvilinear pattern. Larval respiration decreased in the water where nitrate was added, but only during stage II. The results demonstrated that nitrate presents extremely low toxicity for giant river prawn larvae, and data were related to the levels of nitrate that usually occur in larviculture systems also discussed. Therefore, nitrate is not a limiting factor for giant river prawn larviculture. © 2003 by The Haworth Press, Inc. All rights reserved.

Investigation of the Genotoxic Potential of the Waters of a River Receiving Tannery Effluents by Means of the in vitro Comet Assay

The comet assay has been described as an efficient tool for the detection of changes in the DNA molecule of cells exposed to contaminating agents in vivo and in vitro. The possible environmental contamination due to the persistence of chromium residues from tannery effluents was determined in the waters of the Córrego dos Bagres stream, Municipal district of Franca/SP, by the comet assay on CHO-K1 cells. Water samples were collected during the four seasons of the year 2001 at three distinct stations along the river. The data suggest that the comet test showed good sensitivity for the environmental monitoring of these waters and indicated that this test can be efficient for the determination of the quality of waters contaminated with effluents containing heavy metal residues such as chromium.

Reproductive biology of the shrimp Rimapenaeus constrictus (Decapoda, Penaeidae) in the ubatuba region of Brazil

Sexual maturity, temporal reproductive pattern, and recruitment of juveniles were examined for the shrimp Rimapenaeus constrictus at three different bays in the Ubatuba region (Mar Virado, Ubatuba, and Ubatumirim), State of São Paulo (23°S 45°W). Monthly samples were taken from January 1998 to December 1999. The presence or absence of mating plugs (associated with mating and insemination) and ovarian maturity were used to examine breeding in adult females. The whole sample comprised 3863 females and 1468 males. Estimates of size (carapace length) at the onset of sexual maturity were 7.0 mm and 7.8 mm for males and females, respectively. Higher percentage of females bearing ripe gonads was observed during spring and summer over the course of the study, contrasting to the low proportion in fall 1998 and winter 1999. Juvenile shrimps were sampled year-round. These results suggest a continuous reproductive pattern for R. constrictus. Mating, spawning, and juvenile recruitment took place mostly in shallow waters up to 20-m depths in the study region. Warm to mild temperatures may favour the spawning pattern observed in this species. The classical paradigm of continuous reproduction at lower latitudes, with increased seasonality of breeding period at higher latitudes, seems to apply to this species.

Aplicação do Índice Relaçáo Declividade-Extensão - RDE Na Bacia do Rio do Peixe (SP) para Detecção de Deformações Neotectô nicas

This paper presents the identification of tectonic deformation through the application of the stream-gradient index (slope x length) method in the Rio do Peixe hydrographic basin, located in western State of Sã o Paulo. The main principle used is that river valleys are the best tools for this type of analysis because of their fast adjustment to even the most gentle crustal deformations. This type of analysis for structural studies is extremely useful in the western region of the State of São Paulo, where deep chemical weathering results in a thick regolith and scarce outcrops. The stream length index is the ratio of the altimetric amplitude of each drainage and the natural logarithm of its length. The value obtained is plotted on maps at the median point of each drainage, allowing the drawings of lines with the same values (isodefs). Three anomalies (A, B and C) were identified along the Rio do Peixe valley representing uplift sectors indicated by the formation and distribution of Upper Quaternary deposits in terraces and modern fluvial plains and alluvial fans. In correlation with known tectonic data for this region it is possible to attribute the A and B anomalies to the Ribeirão Preto and Presidente Prudente crustal sutures, respectively. The smaller C anomaly needs further field investigation, but it could be associated with the Três Lagoas crustal suture. It must be emphasised that these sutures are inherited from the Precambrian Basement which had a strong influence on the Phanerozoic evolution in the whole sedimentary and volcanic stratigraphic pile of the Paraná Basin and on the dominant structural lineaments directions developed therein .The A, Band C anomalies are suggestive of renewed uplift as a result of neotectonic action in modern times.

GPR survey in the Taquari River, Pantanal Wetland, west-central Brazil

A pioneer GPR - Ground Penetrating Radar - survey was carried out in the Pantanal of Mato Grosso State, westcentral region of Brazil. Fieldwork acquisitions were carried out in February/2001 and August/2002 in order to understand avulsion processes that are occurring within the Taquari alluvial megafan. The main subjects were to map channel, crevasses and floodplain morphology, as well as active sedimentary bedforms. Many GPR profiles were surveyed in the medium and lower Taquari River course. Subaqueous megaripples and exposed sand bars inside the Taquari channel were identified in the medium fan area. Similar features were observed in the lower fan channels, where there are also many crevasses in the marginal levees. During the flooding seasons the flow splays out in the floodplain where new distributary channels are being formed. As shown by GPR data, in the lower fan the Taquari channel is topographically higher than the adjacent floodplain, situation in which avulsion is a natural process of river course shifting. The lack of information about river morphology and dynamics is a major strain to better understand the sediment transport and the avulsion processes in the Taquari megafan. In this context, the GPR data obtained in wet and dry seasons, integrated to sedimentological information, have been very important to characterize the fluvial dynamics and the avulsion phenomena.

Reproductive ecology of the freshwater red alga Batrachospermum delicatulum (Batrachospermales, Rhodophyta) in three tropical streams

Batrachospermum delicatulum specimens from three stream segments were analyzed from a tropical region in south-eastern Brazil (20°18′- 20°49′S, 49°13′-49°46′W). Physical and chemical parameters and the spatial placement of thalli were investigated along with the reproductive characteristics of the gametophytic phase. Sequence data of the cox 2-3 spacer region was also utilized to evaluate genetic variation in individuals within and among stream segments. Gametophyte occurred under relatively diverse environmental conditions, whereas thalli abundance was weakly or not correlated to environmental variables within the stream segments. All specimens examined were dioecious. The ratio of male/female plants was relatively low (0.5 to 1.3) and male plants tended to occur as clumps (two or three plants together). High reproductive success was observed, as indicated by the occurrence of 100% fertilized (carposporophytic) female plants. This is similar to previous reports for this and other dioecious species, which is remarkable considering the relatively low proportion of male/female plants. Results support the two hypotheses to explain the high reproductive success in dioecious species. The occurrence of male plants in clumps was evidence for a strict spatial relationship (i.e. male plants located in upstream position of female plants in order to release spermatia, which would be carried by eddies through female plants). In contrast, the occurrence of male and female plants adjacent to each other allowed outcrossing among neighboring plants with intermingled male and female branches, which seemed more applicable to some situations (low turbulence habitats). The cox 2-3 spacer region from the 18 individuals sequenced was 376 bp and the DNA sequence was identical with no base pair substitutions. Likewise, a previous study of another Batrachospermum species showed that the same haplotypes were present in all stream segments from the same drainage basin, even though the stream segments were a considerable distance apart. Short distance dispersal either by small birds or waterway connectivity might explain these findings.

Localization of rDNA sites in holocentric chromosomes of three species of triatomines (Heteroptera, Triatominae).

Chromatin organization in the holocentric chromosomes of three triatomines species was cytologically studied by fluorescent in situ hybridization with a 45S rDNA probe of Drosophila melanogaster to localize ribosomal genes. In Triatoma tibiamaculata, metaphases I showed telomeric highlights in a single, larger bivalent. In T. protacta, hybridization was detected in one of the telomeres of an autosomal chromosome. In T. platensis, there were highlights in a single, smaller chromosome (X chromosome). The results obtained did not agree with the expected localization of rDNA genes in the sex chromosomes of triatomines, as demonstrated by silver impregnation, and suggest that the chromosome reorganization that occurred in this group during evolution may be a more important mechanism involved in rDNA distribution.

Comparative morphology of the ileum of three species of Cephalotes (formicidae, myrmicinae)

The histology (H.E.), histochemistry (carbohydrates, proteins, collagen, and calcium), enzyme profile (ATPase and Acid phosphatase), and ultramorphology of the ileum of Cephalotes atratus, C. clypeatus and C. pusillus were studied in order to obtain some information about the similarities of these species. The relationship among these three species, as well as the results obtained for the wall, and the contents of this portion of the digestive tract were discussed. In C. clypeatus the ileum is somewhat smaller than that of C. atratus, despite the similarities in body size. The ATPase results showed 2 different regions: the anterior region responsible for absorbing material from the haemolymph and the posterior region for absorbtion from the ileum lumen. Other histochemical analyses failed to show any differences.

Cytogenetical analyses in three Astyanax scabripinnis populations (Pisces, Characidae) from Minas Gerais State, Brazil

Cytogenetical data in 3 populations of characid fish assigned to the complex of Astyanax scabripinnis from São Francisco river basin and Grande river basin, Minas Gerais State, Brazil, are presented for the first time. The same diploid number, 2n=50, was detected in the 3 populations, which has conspicuous differences involving karyotype morphology: 8M, 20SM, 6ST and 16A (Cambeba stream), 6M, 28SM, 6ST and 10A (Machado headwater), 6M, 24SM, 8ST and 12A (Pedra Branca stream). Differences involving amount and/or locations of heterochromatin blocks, number and position of nucleolar organizer regions (NORs) and CMA3 positive signals were also observed. Some aspects related to the chromosome diversification of Astyanax scabripinnis are discussed. © 2007 The Japan Mendel Society.

Economic Survey of Latin America and the Caribbean 2013: Three decades of uneven and unstable growth

Includes bibliography

Hemoglobin polymorphism and hematological profile of Geoffroy's side-necked turtle (Phrynops geoffroanus, Testudines) in the northwestern region of São Paulo State, Brazil

Complete blood counts and hemoglobin isoform data were gathered from 36 specimens of the turtle species Phrynops geoffroanus from the northwestern region of São Paulo State, Brazil. They were collected in an urban area. The hemoglobin profiles were obtained after red blood cell lysis and by electrophoretic migration in alkaline pH, acid pH, and neutral pH buffer. The hemoglobin components were confirmed using high-performance liquid chromatography (HPLC). Erythrogram analysis included hematocrit, total hemoglobin concentration, total red blood cell count, and red blood cell indices. The leukogram included a total white blood cell count and a calculation of the percent values of neutrophils, lymphocytes, monocytes, basophils, eosinophils, heterophils, and azurophils. HPLC analysis revealed three hemoglobin components; the first with a concentration of 5.5%, the second was a major component with an average concentration of 67.1%, and the third with a concentration of 28.5%. The hematological profile obtained for these specimens allowed us to establish a pattern for P. geoffroanus in São Paulo State Northwestern region. The average hematocrit values were 22.5% for females and 24.0% for males. For total hemoglobin, we found average values of 6.66 g/dL in females and 7.22 g/dL in males. The number of white blood cells was 2725 x 103/μL for females and 2775 x 103/μL for males. There was a predominance of heterophils, eosinophils, and monocytes in both sexes. No significant differences were found between males and females for hematological profile. The hematological results were compared to literature data for other Chelonia. They were similar to what is known for fresh water turtles. © FUNPEC-RP.

Spermatogenesis and karyotypes of three species of water striders (Gerridae, Heteroptera).

Although they are of economic importance, there have been few cytogenetic studies of the Gerridae (Heteroptera) in Brazil. We examined spermatogenesis (meiosis and spermiogenesis) and nucleolar behavior in three species of the family Gerridae. Brachymetra albinerva and Halobatopsis platensis were found to have a chromosome complement of 2n = 25 (24A + X0) and Cylindrostethus palmaris 2n = 29 (28A + X0) chromosomes. Fifteen individuals of these species were collected from the reservoir of São José do Rio Preto, SP, using screens and were transported in pots containing water to the laboratory, where cytogenetic preparations were made. The polyploidy nuclei are formed by several heteropyknotic regions; cells in meiotic prophase have a heteropyknotic region that is probably the sex chromosome, and the chromosomes from chiasmata. The spermatids are rounded and have a heteropyknotic region at the periphery of the nucleus; the sperm head is small, with a long tail. Silver impregnation of meiotic cells showed one or more disorganized bodies around the perichromosomal sheath. The round spermatids had two bodies next to each other, but these were elongated; one of the bodies remained in the head and the other migrated to the initial part of the tail at the end of spermagenesis, when the staining was no longer evident. The meiotic cells appear during spermatogenesis and have very similar silver-impregnation patterns in different species of Heteroptera.

Development of a water quality index using a fuzzy logic: A case study for the sorocaba river

Due to growing urbanization and industrialization, the environment is suffering from pollution of rivers, degradation of soils and deteriorated air quality. Quality indices appear to be useful to evaluate the conditions of these media. The aim of this study was the development of a water quality index using a fuzzy inference system, since such an approach has proved advantageous in addressing problems that are subjective by nature or for which the data are uncertain. The methodology employed was based on this inference system, and considered the nine water quality parameters employed by CETESB (Companhia de Tecnologia de Saneamento Ambiental, São Paulo, Brazil) to evaluate water quality. After assessment of the data using the index, a comparison was made with the WQI (Water Quality Index), which is used for the monitoring of various water bodies, including in the study region. The results obtained using the index developed on the basis of fuzzy inference were found to be more useful than those derived from the method currently used by CETESB, since losses and/or omissions concerning individual parameters were minimized. © 2010 IEEE.

Vascular plants of oxbow lakes of Turvo River, Upper Paraná River basin, São Paulo State, Brazil

Vascular plants were investigated in oxbow lakes of Turvo River, Upper Paraná River basin, between Icém and Nova Granada municipalities, state of São Paulo, Brazil. In this region, six lagoons were sampled: Ganzella, Mustafá, Braço Morto, 45, Federal, and Parente. The survey showed a total of 54 species, 36 genera and 22 families. The species richest families were Poaceae, Cyperaceae, and Polygonaceae. Eichhornia crassipes (Pontederiaceae) was the single species encountered in all the six lakes. © 2010 Check List and Authors.