A multi-evidence approach in an Amazonian river based on land use, water quality, histopathological effects and habitat selection behavior in fish.

The Amazon rivers constitute the largest river basin in the world, with a high level of biodiversity. The Tocantins River is one of the most important rivers in this region, which has been impacted by different land uses. The objective of this study was to carry out a multi-evidence analysis focusing on the water quality of the Tocantins River, close to the municipality of Marabá-PA. We analyzed forest cover and water quality and, using the model organism Danio rerio, performed toxicity tests for histopathological effects, as well as the habitat selection approach by exposing fish to different river water samples in a multi-compartment device. The results showed that the studied area has already lost almost 30% of its forests in recent decades. Regarding water quality, the upstream (C1) and downstream (C5) points are the least impacted. On the other hand, the other points (C2-C4), closer to the city, greater input of pollutants was detected. Fish exposed to water samples from the most impacted sites showed several oedemas and hyperplastic cells in the gills. Regarding habitat selection behavior, there was a marked avoidance by samples with the highest contamination load. The results of this study lead to the understanding of the potential negative effects of human activities on local Amazonian biodiversity, since the potential toxicity of the environment, in conjunction with changes in the habitat selection process, could lead to a decline in populations of aquatic organisms, altering the environmental balance.

Fishers' knowledge on abundance and trophic interactions of the freshwater fish Plagioscion squamosissimus (Perciformes: Sciaenidae) in two Amazonian rivers

Small-scale fisheries provide income and food security to local peoples around the world. In the Brazilian Amazon, the pescada (Plagioscion squamosissimus) is among the fishes that contributes most to catches in small-scale fisheries. Our main goal was to evaluate the abundance, size, relevance to small-scale fisheries and trophic ecology of P. squamosissimus in the Tapajós and Tocantins rivers, in the Brazilian Amazon. We combined data from fishers' local ecological knowledge (LEK) and fish sampling. We expected that fishers in the Tapajós River, less altered by anthropic changes, would cite a higher abundance, larger size and more prey and predators of P. squamosissimus. We interviewed 61 and 33 fishers and sampled fish in nine and five sites in the Tapajós and Tocantins rivers, respectively. The comparison between fishers' citations and fish sampled indicated a higher relevance of P. squamosissimus to fishers in the Tapajós River, where this fish had an average larger size and where the fishers mentioned more food items. This pattern could be partially related to the history of anthropogenic changes in the Tocantins River. These results indicated that P. squamosissimus is a generalist fish, which could be resilient to fishing and environmental pressures.(AU)

A pesca de pequena escala fornece renda e segurança alimentar para as populações locais em todo o mundo. Na Amazônia brasileira, a pescada (Plagioscion squamosissimus) está entre os peixes que mais contribuem para as capturas em pescarias de pequena escala. Nosso objetivo principal foi avaliar a abundância, tamanho, relevância para a pesca artesanal e ecologia trófica de P. squamosissimus nos rios Tapajós e Tocantins, na Amazônia brasileira. Combinamos dados do conhecimento ecológico local dos pescadores (CEL) e amostragem de peixes. Esperávamos que os pescadores do rio Tapajós, menos alterado por mudanças antrópicas, citassem maior abundância, maior tamanho e mais presas e predadores de P. squamosissimus. Entrevistamos 61 e 33 pescadores e amostramos peixes em nove e cinco locais nos rios Tapajós e Tocantins, respectivamente. A comparação entre as citações dos pescadores e os peixes amostrados indicou uma maior relevância de P. squamosissimus para os pescadores do rio Tapajós, onde este peixe teve um tamanho médio maior e onde os pescadores mencionaram mais itens alimentares. Esse padrão pode estar parcialmente relacionado ao histórico de mudanças antrópicas no rio Tocantins. Esses resultados indicaram que P. squamosissimus é um peixe generalista, que pode ser resiliente à pesca e às pressões ambientais.(AU)

Diversity of Nematoda and Digenea from different species of characiform fishes from Tocantins River, Maranhão, Brazil / Diversidade de Nematoda e Digenea coletados em diferentes espécies de Characiformes provenientes do rio Tocantins, Maranhão, Brasil

During a survey of the helminth fauna of characiform fishes from the Tocantins River, Brazil, 185 fish specimens from 22 species were studied. Twelve species of Nematoda and nine species of Digenea were collected. Some of these helminth species were reported for the first time in their hosts, thus representing new host records: Procamallanus (Spirocamallanus) sp. in Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis and Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus in Triportheus elongatus; Goezia sp. (larva) in Boulengerella cuvieri; Rhabdochona acuminata in Brycon pesu and Triportheus trifurcatus; Raphidascaris sp. (larva) in Caenotropus labyrinthicus; Cosmoxynema vianai in Cyphocharax gouldingi; Rondonia rondoni in Leporinus fasciatus and Mylesinus paucisquamatus; Klossinemella iheringi in Mylesinus paucisquamatus; Cucullanidae gen. sp. in Myloplus rubripinnis; Rhabdochona sp. in Triportheus elongatus; Alphamphistoma sp. in Myleus setiger; Chalcinotrema sp. in Cyphocharax gouldingi; Pacudistoma guianense in Hemiodus unimaculatus and Myleus torquatus; Pseudocladorchis cylindricus in Hemiodus unimaculatus; Dadaytrema oxycephala in Mylesinus paucisquamatus; Travassosinia dilatata in Myloplus asterias; and Genarchella genarchella in Raphiodon vulpinus. Studies identifying new hosts and new localities for parasites have contributed to the knowledge of local biodiversity. A list of previous records of helminths included in the present study, providing hosts, localities, and references, is presented here.(AU)

Durante a pesquisa da fauna helmintológica de Characiformes do rio Tocantins, Maranhão, Brasil, 185 peixes pertencentes a 22 espécies foram estudados. Doze espécies de Nematoda e nove espécies de Digenea foram coletadas. Algumas espécies de helmintos estão sendo registradas pela primeira vez em seus hospedeiros, representando novos registros: Procamallanus (Spirocamallanus) sp. em Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis e Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus em Triportheus elongatus; Goezia sp. (larva) em Boulengerella cuvieri; Rhabdochona acuminata em Brycon pesu e Tripotheus trifurcatus; Raphidascaris sp. (larva) em Caenotropus labyrinthicus; Cosmoxynema vianai em Cyphocharax gouldingi; Rondonia rondoni em Leporinus fasciatus e Mylesinus paucisquamatus; Klossinemella iheringi em Mylesinus paucisquamatus; Cucullanidae gen. sp. em Myloplus rubripinnis; Rhabdochona sp. em Triportheus elongatus; Alphamphistoma sp. em Myleus setiger; Chalcinotrema sp. em Cyphocarax gouldingi; Pacudistoma guianense em Hemiodus unimaculatus e Myleus torquatus; Pseudocladorchis cylindricus em Hemiodus unimaculatus; Dadaytrema oxycephala em Mylesinus paucisquamatus; Travassosinia dilatata em Myloplus asterias; e Genarchella genarchella em Raphiodon vulpinus. Estudos que identificam novos hospedeiros e novas localidades para parasitos têm contribuído para o conhecimento da biodiversidade local. Uma lista dos registros prévios dos helmintos incluídos no presente estudo, com hospedeiros, localidades e referências é apresentada.(AU)

Avian extinctions induced by the oldest Amazonian hydropower mega dam: evidence from museum collections and sighting data spanning 172 years.

Hydroelectric dams represent an emergent threat to lowland tropical forest biodiversity. Despite the large number of operational, under-construction, and planned hydroelectric dams, their long-term effects on biodiversity loss are still poorly documented. Here, we investigate avian extinctions resulting from the Tucuruí Hydroelectric Reservoir (THR), the oldest Amazonian mega dam, which impounded the Tocantins River in 1984. Our avian inventory-based on several sampling methods (mist-netting, point-counts, boat census and qualitative surveys) during 280 days of fieldwork from 2005 to 2007-was combined with an exhaustive search of museum vouchers and digital online databases of citizen science from the lower Tocantins River to identify long-term trends in species persistence and extinction in the THR influence area. The regional avifauna was comprised of 479 species, 404 of which were recorded during our fieldwork. Based on recent and historical records spanning 172 years, we found evidence for likely extinctions at THR influence area for 53 (11.06%) species that have remained entirely unreported since 1984. We were further able to estimate extinction probabilities for 20 species; 15 species were considered to be extinct, including Psophia interjecta and Pyrilia vulturina that are red-listed by IUCN. Our study serves as a baseline for avifaunal monitoring in the THR influence area and shows that degree of habitat specialization is a key factor in determining species extinctions caused by nonrandom habitat loss from either inundation or deforestation. Avian species extinctions will most likely continue across the area affected by the reservoir as a direct impact of alluvial forest loss and ongoing habitat degradation of upland forests.

Coelozoic parasite of the family Ceratomyxidae (Myxozoa, Bivalvulida) described from motile vermiform plasmodia found in Hemiodus unimaculatus Bloch, 1794.

Myxozoans of the family Ceratomyxidae are common coelozoic parasites of marine, anadromous, and freshwater fish, and may also be found, less frequently, parasitizing the tissue of these hosts. The diversity and ecology of the freshwater species of the genus Ceratomyxa have been poorly investigated, leading to a knowledge gap that restricts the understanding of the distribution and prevalence of this group of parasites. In the present study, parasites were found inside vermiform plasmodia, characterised by oscillatory movements in the characiform species Hemiodus unimaculatus. The crescent-shaped and elongated spores, perpendicular to the suture line, have a mean length of 28.9 ± 2.7 µm and width of 2.6 ± 0.1 µm, with two symmetrical oval polar capsules, 1.9 ± 0.3 µm in length and 1.7 ± 0.2 µm in width, containing polar filaments with three or four coils, located near the central suture, with symmetrical lateral elongations 14.3 ± 1.1 µm in length and binucleate amoeboid sporoplasm. The integrated comparative analysis of the morphological characteristics and partial SSU rRNA sequences supported the identification of a new species of coelozoic Ceratomyxa, found in the gallbladder of H. unimaculatus, from the Tocantins basin, in the municipalities of Estreito and Imperatriz in eastern Brazilian Amazonia.The new species was denominated Ceratomyxa fonsecai n. sp.

Morphology and Phylogeny of Calyptospora paranaidji n. sp. (Eimeriorina: Calyptosporidae), an Apicomplexan Parasite of the Hepatic Tissue of Cichla piquiti Kullander & Ferreira, 2006, From a Reservoir in the Brazilian Amazon Region.

The coccidians of the family Calyptosporidae are parasites of the tissue and organs of fish and aquatic invertebrates, in particular in the tropical region. In contrast with other apicomplexans of the suborder Eimeriorina, the diversity and ecology of the species of the genus Calyptospora have been poorly investigated, resulting in a lacuna that restricts the understanding of the distribution and prevalence of this group of eukaryote microparasites in the Amazon region. In the present study, the integrated comparative analysis of morphological characteristics, histological and structural traits, and the sequences of a fragment of the 18S rRNA gene, provides support for the identification of a new species of Calyptospora, found parasitizing the hepatic tissue of the piscivorous blue peacock bass, Cichla piquiti, captured in the reservoir of the Estreito hydroelectric dam on the middle Tocantins River in northern Brazil. This new species was named Calyptospora paranaidji n. sp.

Remarkable Geographic Structuring of Rheophilic Fishes of the Lower Araguaia River.

Rapids and waterfalls, and their associated fauna and flora are in peril. With the construction of each new hydroelectric dam, more rapids and waterfalls are destroyed, leading to the disappearance of associated fauna and flora. Areas of rapids harbor distinct, highly endemic rheophilic fauna and flora adapted to an extreme environment. Rheophilic habitats also have disjunct distribution both within and across rivers. Rheophilic habitats thus represent islands of suitable habitat separated by stretches of unsuitable habitat. In this study, we investigated to what extent, if any, species of cichlid and anostomid fishes associated with rheophilic habitats were structured among the rapids of Araguaia River in the Brazilian Amazon. We tested both for population structuring as well as non-random distribution of lineages among rapids. Eight of the nine species had multiple lineages, five of these nine species were structured, and three of the eight species with multiple lineages showed non-random distribution of lineages among rapids. These results demonstrate that in addition to high levels of endemicism of rheophilic fishes, different rapids even within the same river are occupied by different lineages. Rheophilic species and communities occupying different rapids are, therefore, not interchangeable, and this realization must be taken into account when proposing mitigatory/compensatory measures in hydroelectric projects, and in conservation planning.

A new species of Notodiaptomus from the Amazon basin (Crustacea, Copepoda, Calanoida, Diaptomidae).

A new Diaptomidae species is presented from the Neotropical region. It was found in two Amazonian lakes, Ressaca and Arapujá, both in Pará State, Brazil. The lakes are 400 km apart and threatened by the building of reservoirs for hydropower generation and pollution by human settlements. The new species resembles N. paraensis Dussart & Robertson, 1984, but it can be distinguished from this species and other congeners in having a special process on the fifth leg basis of the male, by the place of insertion of lateral spine in the last segment of right P5 of male, the shape and relationship between length and width of segments of male and female P5 exopodite 2 with stout inner process bearing short setules and outer small spine, exopodite 3, with two terminal setae, outer smaller; endopodite 1-segmented with one subterminal seta and oblique comb of spinules, the presence of a line of dorsal spinules at the distal margin of thoracic somites in both sexes. A brief comparison with other Notodiaptomus species is presented in the discussion.

Larval and juvenile development of Tatia intermedia (Siluriformes: Auchenipteridae).

This study describes the morphology, morphometry and meristic characters of larval and juvenile Tatia intermedia collected in the middle Tocantins River and some of its tributaries. Six larvae of T. intermedia were examined and they have a moderately elongate body, head slightly dorso-ventrally depressed with a convex snout, small and round eyes and a subterminal mouth. In five juvenile stages observed, the head and eye are relatively smaller than in the larval stage and the snout remains convex and mouth becomes terminal.

Artisanal fishermen downstream of Tucuruí Hydroelectric Power Plant, Amazon, Brazil / Pescadores artesanais à jusante da Usina Hidrelétrica de Tucuruí, Amazônia, Brasil

Fishing is one of the most traditional activities downstream Tucuruí dam, northeast Pará state, generating occupation to many coastal families. The main fishing tackles used in the study area are the fishing nets and the main species are Plagioscion squamosissimus (Heckel, 1840) and Hypophthalmus marginatus (Valenciennes in Cuvier and Valenciennes, 1840. Most of the fish are sell cold. The socioeconomic characterization was conduct through semi-structured interviews using questionnaires with 109 anglers during June, August and September 2006 and April 2008. Respondents were mostly born in Para state (98%), male (89%), lived under a stable relationship (38%), 82.6% had children; family income of the majority was below the minimum wage (67%) and aged between 14 and 70 years, with incomplete secondary education (62%), about 27% of the fishermen are working on fisheries at last 5 to 9 years. The anglers interviewed associated fish stocks decline to factors such as use of fishing tackles out of specifications established in legislation.

A pesca é uma das atividades mais tradicionais realizadas a jusante da Usina Hidrelétrica de Tucuruí, nordeste paraense, gerando emprego e renda a inúmeras famílias ribeirinhas. O apetrecho de pesca mais utilizado na área de estudo é a rede de emalhar fixa e as principais espécies capturadas são a pescada branca (Plagioscion squamosissimus) e o mapará (Hypophthalmus marginatus). A maior parte do pescado é comercializada fresco. A caracterização socioeconômica dos pescadores foi realizada por meio entrevistas semiestruturadas, com questionários aplicados a 109 pescadores nos meses de junho, agosto e setembro de 2006 e em abril de 2008. Os entrevistados, em sua maioria, são paraenses (98%), homens (89%) que vivem em regime de união estável (38%), 82,6% possuem filhos; a renda familiar é inferior a um salário mínimo (67%) e possuem idade entre 14 e 70 anos, com ensino médio incompleto (62%), e cerca de 27% exerce a atividade a um tempo que varia entre 5 a 9 anos. Para os pescadores entrevistados há redução na produção pesqueira associada a fatores como uso de apetrechos de pesca fora das especificações previstas na legislação.

Artisanal fishermen downstream of Tucuruí Hydroelectric Power Plant, Amazon, Brazil / Pescadores artesanais à jusante da Usina Hidrelétrica de Tucuruí, Amazônia, Brasil

Fishing is one of the most traditional activities downstream Tucuruí dam, northeast Pará state, generating occupation to many coastal families. The main fishing tackles used in the study area are the fishing nets and the main species are Plagioscion squamosissimus (Heckel, 1840) and Hypophthalmus marginatus (Valenciennes in Cuvier and Valenciennes, 1840. Most of the fish are sell cold. The socioeconomic characterization was conduct through semi-structured interviews using questionnaires with 109 anglers during June, August and September 2006 and April 2008. Respondents were mostly born in Para state (98%), male (89%), lived under a stable relationship (38%), 82.6% had children; family income of the majority was below the minimum wage (67%) and aged between 14 and 70 years, with incomplete secondary education (62%), about 27% of the fishermen are working on fisheries at last 5 to 9 years. The anglers interviewed associated fish stocks decline to factors such as use of fishing tackles out of specifications established in legislation.(AU)

A pesca é uma das atividades mais tradicionais realizadas a jusante da Usina Hidrelétrica de Tucuruí, nordeste paraense, gerando emprego e renda a inúmeras famílias ribeirinhas. O apetrecho de pesca mais utilizado na área de estudo é a rede de emalhar fixa e as principais espécies capturadas são a pescada branca (Plagioscion squamosissimus) e o mapará (Hypophthalmus marginatus). A maior parte do pescado é comercializada fresco. A caracterização socioeconômica dos pescadores foi realizada por meio entrevistas semiestruturadas, com questionários aplicados a 109 pescadores nos meses de junho, agosto e setembro de 2006 e em abril de 2008. Os entrevistados, em sua maioria, são paraenses (98%), homens (89%) que vivem em regime de união estável (38%), 82,6% possuem filhos; a renda familiar é inferior a um salário mínimo (67%) e possuem idade entre 14 e 70 anos, com ensino médio incompleto (62%), e cerca de 27% exerce a atividade a um tempo que varia entre 5 a 9 anos. Para os pescadores entrevistados há redução na produção pesqueira associada a fatores como uso de apetrechos de pesca fora das especificações previstas na legislação.(AU)

Composição e variabilidade da comunidade de rotifera em um reservatório tropical / Composition and variability of the rotifers community in a tropical reservoir

The rotifer community from the hydroelectric power plant "s reservoir of Tucuruí, Northern Brazil was studied as the rotifer community composition and the answer to it in relation to spatial and temporal variations in the region, correlating them with phytoplankton. Samples of rotifer and phytoplankton communities were collected on the surface with plankton nets (60 and 20 µm respectively) in ten locations distributed upstream and downstream of the UHE and during both rainy and dry seasons. In relation to the frequency, 29 rotifer and 19 phytoplankton taxa were considered very frequent, from which the rotifers Keratella americana, K. cochlearis and Rotaria sp., and the microalgae Eudorina elegans, Micrasterias radiata and Microcystis aeruginosa were the dominant species. The ecological indexes estimated here showed no significant spatial and temporal variations, suggesting that the rotifer community is possibly resilient to seasonal disturbances, since most taxa sampled are uniformly distributed in the area.

A comunidade de rotíferos do reservatório da Usina Hidrelétrica de Tucuruí, Norte do Brasil foi estudada quanto à sua composição e resposta frente a variações espaciais e temporais na região, correlacionando-as com o fitoplâncton. Amostras da comunidade de rotíferos e de fitoplâncton foram coletadas na superfície, com redes de plâncton (60 e 20 µm, respectivamente), em dez pontos distribuídos a montante e a jusante da UHE e nos meses de maior e menor precipitação. Em relação à frequência, 29 táxons de rotíferos e 19 de fitoplâncton foram considerados muito frequentes, dentre os quais, os rotíferos Keratella americana, K. cochlearis e Rotaria sp. e as microalgas Eudorina elegans, Micrasterias radiata e Microcystis aeruginosa foram as espécies dominantes. Os índices ecológicos não apresentaram variações espaciais e temporais significativas para os rotíferos, sugerindo uma possível resiliência frente aos distúrbios temporais, com uniformidade na distribuição dos táxons registrados.

Composição e variabilidade da comunidade de rotifera em um reservatório tropical / Composition and variability of the rotifers community in a tropical reservoir

The rotifer community from the hydroelectric power plant "s reservoir of Tucuruí, Northern Brazil was studied as the rotifer community composition and the answer to it in relation to spatial and temporal variations in the region, correlating them with phytoplankton. Samples of rotifer and phytoplankton communities were collected on the surface with plankton nets (60 and 20 µm respectively) in ten locations distributed upstream and downstream of the UHE and during both rainy and dry seasons. In relation to the frequency, 29 rotifer and 19 phytoplankton taxa were considered very frequent, from which the rotifers Keratella americana, K. cochlearis and Rotaria sp., and the microalgae Eudorina elegans, Micrasterias radiata and Microcystis aeruginosa were the dominant species. The ecological indexes estimated here showed no significant spatial and temporal variations, suggesting that the rotifer community is possibly resilient to seasonal disturbances, since most taxa sampled are uniformly distributed in the area.(AU)

A comunidade de rotíferos do reservatório da Usina Hidrelétrica de Tucuruí, Norte do Brasil foi estudada quanto à sua composição e resposta frente a variações espaciais e temporais na região, correlacionando-as com o fitoplâncton. Amostras da comunidade de rotíferos e de fitoplâncton foram coletadas na superfície, com redes de plâncton (60 e 20 µm, respectivamente), em dez pontos distribuídos a montante e a jusante da UHE e nos meses de maior e menor precipitação. Em relação à frequência, 29 táxons de rotíferos e 19 de fitoplâncton foram considerados muito frequentes, dentre os quais, os rotíferos Keratella americana, K. cochlearis e Rotaria sp. e as microalgas Eudorina elegans, Micrasterias radiata e Microcystis aeruginosa foram as espécies dominantes. Os índices ecológicos não apresentaram variações espaciais e temporais significativas para os rotíferos, sugerindo uma possível resiliência frente aos distúrbios temporais, com uniformidade na distribuição dos táxons registrados.(AU)

Ituglanis boticario, a new troglomorphic catfish (Teleostei: Siluriformes: Trichomycteridae) from Mambaí karst area, central Brazil

A new subterranean and troglomorphic species of Ituglanis Costa and Bockmann, 1993 is described from the carbonatic karst area of northeastern Goiás state, upper Tocantins River Basin, central Brazil, representing the sixth subterranean species of the genus described from the same region. Ituglanis boticario sp. nov. is diagnosed by a combination of unusual characters for the genus: body pigmentation forming longitudinal stripes, 7-8 pairs of ribs, presence of the anterior segment of the infraorbital laterosensory canal, and usually 8 pectoral-fin rays. Due to the absence of epigean populations and the presence of some degree of morphological specialization to the subterranean environment, it can be classified as a troglobite (i.e., exclusively subterranean). The description of this species increases the importance of the northeastern Goiás region as a biodiversity spot for subterranean ichthyofauna, mainly Ituglanis. The region demands urgent political efforts to ensure the preservation of its speleobiological patrimony, including the Tarimba cave system, one of the largest caves in Brazil and type-locality of I. boticario sp. nov.

Ituglanis boticario, a new troglomorphic catfish (Teleostei: Siluriformes: Trichomycteridae) from Mambaí karst area, central Brazil

A new subterranean and troglomorphic species of Ituglanis Costa and Bockmann, 1993 is described from the carbonatic karst area of northeastern Goiás state, upper Tocantins River Basin, central Brazil, representing the sixth subterranean species of the genus described from the same region. Ituglanis boticario sp. nov. is diagnosed by a combination of unusual characters for the genus: body pigmentation forming longitudinal stripes, 7-8 pairs of ribs, presence of the anterior segment of the infraorbital laterosensory canal, and usually 8 pectoral-fin rays. Due to the absence of epigean populations and the presence of some degree of morphological specialization to the subterranean environment, it can be classified as a troglobite (i.e., exclusively subterranean). The description of this species increases the importance of the northeastern Goiás region as a biodiversity spot for subterranean ichthyofauna, mainly Ituglanis. The region demands urgent political efforts to ensure the preservation of its speleobiological patrimony, including the Tarimba cave system, one of the largest caves in Brazil and type-locality of I. boticario sp. nov.(AU)

Abundance and length structure of Brycon nattereri (Osteichthyes, Bryconidae), an endangered fish species in central Brazil / Abundância e estrutura de comprimento de Brycon nattereri (Osteichthyes, Bryconidae), uma espécie de peixe ameaçada do Brasil central

Brycon nattereri is a threatened fish species restricted to small headwater rivers of the Paraná, São Francisco and Tocantins rivers. This species has been extirpated from many sites, and little is known about its ecology. In this sense, the present study investigated temporal variations in the occurrence, abundance and length structure of B. nattereri in the Dois Irmãos river, a small headwater river from the Tocantins river basin. Samples were taken monthly between January and November of 2009 and 2010. The studied site comprised a 4.5 km river stretch, sampled with an active fishing method (fly fishing). Individuals caught were counted, measured and returned immediately to the river. We caught 302 individuals along two years. Brycon nattereri was present in the studied stretch in all sampling months, with higher abundance between November and May (wet season). We registered a wide range of lengths, with predominance of adult fish; young were captured in July and August, indicating recruitment in the region. The present study, therefore, showed that populations of B. nattereri, an endangered fish species, still persist in small headwater rivers of the upper Tocantins river.

Brycon nattereri é uma espécie de peixe ameaçada restrita a pequenos rios de cabeceira dos rios Paraná, São Francisco e Tocantins. Esta espécie tem sido extirpada de muitos locais, e pouco se sabe sobre sua ecologia. Neste sentido, o presente estudo investigou as variações temporais na ocorrência, abundância e estrutura de comprimento de B. nattereri no rio Dois Irmãos, um pequeno rio de cabeceira da bacia do rio Tocantins. As amostras foram coletadas mensalmente entre janeiro e novembro de 2009 e 2010. A área de estudo compreendeu um trecho de 4,5 km do rio amostrados com um método de pesca ativa (pesca com mosca). Indivíduos capturados foram contados, medidos e imediatamente liberados para o rio. Foi capturado um total de 302 indivíduos ao longo do período dois anos. Brycon nattereri esteve presente no trecho estudado em todos os meses de amostragem, com maior abundância entre novembro e maio (estação chuvosa). Registramos uma ampla gama de comprimentos, com predominância de peixes adultos. Jovens foram capturados em julho e agosto, indicando que o recrutamento está ocorrendo na região. O presente estudo, portanto, mostra que as populações de B. nattereri, uma espécie de peixe ameaçada de extinção, ainda persiste em pequenos rios de cabeceira do alto rio Tocantins.

Abundance and length structure of Brycon nattereri (Osteichthyes, Bryconidae), an endangered fish species in central Brazil / Abundância e estrutura de comprimento de Brycon nattereri (Osteichthyes, Bryconidae), uma espécie de peixe ameaçada do Brasil central

Brycon nattereri is a threatened fish species restricted to small headwater rivers of the Paraná, São Francisco and Tocantins rivers. This species has been extirpated from many sites, and little is known about its ecology. In this sense, the present study investigated temporal variations in the occurrence, abundance and length structure of B. nattereri in the Dois Irmãos river, a small headwater river from the Tocantins river basin. Samples were taken monthly between January and November of 2009 and 2010. The studied site comprised a 4.5 km river stretch, sampled with an active fishing method (fly fishing). Individuals caught were counted, measured and returned immediately to the river. We caught 302 individuals along two years. Brycon nattereri was present in the studied stretch in all sampling months, with higher abundance between November and May (wet season). We registered a wide range of lengths, with predominance of adult fish; young were captured in July and August, indicating recruitment in the region. The present study, therefore, showed that populations of B. nattereri, an endangered fish species, still persist in small headwater rivers of the upperTocantins river.(AU)

Brycon nattereri é uma espécie de peixe ameaçada restrita a pequenos rios de cabeceira dos rios Paraná, São Francisco e Tocantins. Esta espécie tem sido extirpada de muitos locais, e pouco se sabe sobre sua ecologia. Neste sentido, o presente estudo investigou as variações temporais na ocorrência, abundância e estrutura de comprimento de B. nattereri no rio Dois Irmãos, um pequeno rio de cabeceira da bacia do rio Tocantins. As amostras foram coletadas mensalmente entre janeiro e novembro de 2009 e 2010. A área de estudo compreendeu um trecho de 4,5 km do rio amostrados com um método de pesca ativa (pesca com mosca). Indivíduos capturados foram contados, medidos e imediatamente liberados para o rio. Foi capturado um total de 302 indivíduos ao longo do período dois anos. Brycon nattereri esteve presente no trecho estudado em todos os meses de amostragem, com maior abundância entre novembro e maio (estação chuvosa). Registramos uma ampla gama de comprimentos, com predominância de peixes adultos. Jovens foram capturados em julho e agosto, indicando que o recrutamento está ocorrendo na região. O presente estudo, portanto, mostra que as populações de B. nattereri, uma espécie de peixe ameaçada de extinção, ainda persiste em pequenos rios de cabeceira do alto rio Tocantins.(AU)

Changes in the relationship between society and nature in the Mezzo-region of Southeastern Pará, Amazon, Brazil

With this work, the authors wish to show some of the alterations in the pattern of relations between society and nature, which have taken place throughout the 20th century in the Parauapebas and Itacaiúnas river valleys, as well as in parts of the Tocantins River valley, in southeastern Pará. This is accomplished through descriptions based on Coudreau's first-hand accounts (1889), transcribed in "Voyage a Itaboca et a L'Itacayuna", published in 1897, which depicts an area almost totally covered by forest. This is followed by a counter view made possible through the LandSat 5 satellite sensors, with images of those valleys in 2001, showing the consequences of society transformations and pressure on natural resources, and above all the dramatic decrease in the size of the forest, reduced to 52 percent of the 63,000 square kilometers analyzed herein.

Neste texto, busca-se demonstrar algumas das alterações ocorridas nos padrões de relações existentes entre sociedade e natureza ocorridas no século XX, nos vales dos rios Parauapebas, Itacaiúnas e em parte do vale rio Tocantins, no sudeste do estado do Pará, o que é feito realizando um resgate das descrições decorrentes do olhar de Coudreau (1889) e transcritas em "Voyage a Itaboca et a L'Itacayuna", publicado em 1897, no qual se descreve uma área quase que integralmente coberta pela floresta. Em seguida, realiza-se uma contraposição, recorrendo a outro olhar, o que é viabilizado pelos sensores do satélite Landsat 5, que imagiaram a área destes vales em 2001, explicitando conseqüências das transformações da sociedade e da pressão sobre recursos naturais mas, sobretudo, a drástica redução da floresta a 52% dos 63 mil km² analisados.

Hematological parameters of native fish species of the Tocantins river, Auchenipterus nuchalis, Psectrogaster amazônica and Squaliforma emarginata (Teleostei, Ostariophysi) - DOI: 10.4025/actascibiolsci.v31i2.1024 / Parâmetros hematológicos de espécies nativas do rio Tocantins, Auchenipterus nuchalis, Psectrogaster amazônica e Squaliforma emarginata (Teleostei, Ostariophysi) - DOI: 10.4025/actascibiolsci.v31i2.1024

This study evaluated the hematological characteristics and erythrocyte morphometry in Auchenipterus nuchalis, Psectrogaster amazonica and Squaliforma emarginata captured in Tocantins river. The samples were taken in the Tocantins river, where blood was collected by puncturing the caudal vein of the animals. The complete hemogram and morphometry of the erythrocytes were determined. Auchenipterus nuchalis (n = 15) showed the largest number of erythrocytes, hemoglobin and hematocrit, followed by P. amazonica (n = 26) and S. emarginata (n = 26). Squaliforma emarginata showed the largest erythrocytes and the smallest number of circulating cells. Squaliforma emarginata also showed the highest number of circulating blast cells (orthochromatic and polychromatophil erythrocytes) in the peripheral blood. These differences can be attributed to respiratory adaptations of a behavioral or physiological nature related to the environment. The highest percentage of lymphocytes was observed in P. amazonica, and of monocytes and neutrophils in A. nuchalis. The variation among the species in the percentages of leucocytes can also be attributed to the niche occupied, favored by exposure to different microorganisms.

Neste estudo, foram avaliadas as características hematológicas e a morfometria de Auchenipterus nuchalis, Psectrogaster amazônica e Squaliforma emarginata, capturados no rio Tocantins. As amostragens foram realizadas no rio Tocantins, onde o sangue foi coletado por punção caudal dos animais, determinando-se hemograma completo e morfometria dos eritrócitos. Auchenipterus nuchalis (n = 15) apresentou maior número de eritrócitos, hemoglobina e hematócrito, seguido de P. amazônica (n = 26) e S. emarginata (n = 26). O tamanho dos eritrócitos foi maior para S. emarginata, mostrando que quanto maior o tamanho dos eritrócitos, menor o número de células circulantes. Squaliforma emarginata também apresentou maior número de blastos (eritrócitos ortocromáticos e policromatófilos) no sangue periférico. Estas diferenças podem ser atribuídas a adaptações respiratórias de natureza comportamental e/ou fisiológicas, relacionadas ao meio ambiente. O maior percentual de linfócitos foi observado em P. amazônica; o de monócitos e neutrófilos, na espécie A. nuchalis. A variação nos percentuais de leucócitos entre as espécies pode estar relacionada ao nicho ocupado, favorecido pela exposição a diferentes microrganismos.

Changes in the relationship between society and nature in the Mezzo-region of Southeastern Pará, Amazon, Brazil

With this work, the authors wish to show some of the alterations in the pattern of relations between society and nature, which have taken place throughout the 20th century in the Parauapebas and Itacaiúnas river valleys, as well as in parts of the Tocantins River valley, in southeastern Pará. This is accomplished through descriptions based on Coudreau's first-hand accounts (1889), transcribed in "Voyage a Itaboca et a L'Itacayuna", published in 1897, which depicts an area almost totally covered by forest. This is followed by a counter view made possible through the LandSat 5 satellite sensors, with images of those valleys in 2001, showing the consequences of society transformations and pressure on natural resources, and above all the dramatic decrease in the size of the forest, reduced to 52 percent of the 63,000 square kilometers analyzed herein.

Neste texto, busca-se demonstrar algumas das alterações ocorridas nos padrões de relações existentes entre sociedade e natureza ocorridas no século XX, nos vales dos rios Parauapebas, Itacaiúnas e em parte do vale rio Tocantins, no sudeste do estado do Pará, o que é feito realizando um resgate das descrições decorrentes do olhar de Coudreau (1889) e transcritas em "Voyage a Itaboca et a L'Itacayuna", publicado em 1897, no qual se descreve uma área quase que integralmente coberta pela floresta. Em seguida, realiza-se uma contraposição, recorrendo a outro olhar, o que é viabilizado pelos sensores do satélite Landsat 5, que imagiaram a área destes vales em 2001, explicitando conseqüências das transformações da sociedade e da pressão sobre recursos naturais mas, sobretudo, a drástica redução da floresta a 52% dos 63 mil km² analisados.