Essential and Non-Essential Elements Levels in Fish Species Highly Consumed in the Middle Miranda River, Brazilian Pantanal.

The present study investigated the levels of As, Ag, Al, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Se, and Zn in muscle samples of six fish species (Pygocentrus nattereri, Serrasalmus marginatus, Mylossoma duriventre, Leporinus friderici, Pimelodus argenteus, and P. pantaneiro) highly consumed by local riverine and non-resident people in middle Miranda River, southern Brazilian Pantanal. Significant differences were detected for Ba, Fe, Mn, and Zn levels among the analyzed species. Pairwise comparison detected significant differences in element levels between species with similar diets, which implies that other factors, instead of species' feeding habits, could be involved in distinct levels of element bioaccumulation. Significant correlations between body size and concentrations were found for Ba in P. nattereri (moderate positive correlation), and for Mn in M. duriventre (weak positive correlation) and P. argenteus (moderate negative correlation). Levels exceeding tolerable daily intake (TDI) were found for Pb maximum concentrations in P. nattereri, M. duriventre, L. friderici, P. argenteus, and P. pantaneiro, and for Cd maximum concentration in P. argenteus. Health risk assessment indicated considerable risk only for the worst-case scenario (calculated from maximum concentrations) for all species. Adopting a Pb monitoring program in biotic and abiotic compartments in Miranda River is strongly recommended.

Hidden Diversity in Eigenmannia (Gymnotiformes: Sternopygidae) Populations from Upper Paraná and Paraguay Rivers.

Eigenmannia is a highly diverse genus within the Sternopygidae family, comprising 30 species. Due to its complex taxonomy, molecular analyses have been crucial for species delimitation within this group. Therefore, the present study presents a genetic analysis using sequences of the mitochondrial gene cytochrome c oxidase subunit 1 (COI) in specimens previously identified through alpha taxonomy as E. correntes (with unpublished data), E. virescens, and E. trilineata, originating from various locations within the Upper Paraná and Paraguay River basins in Brazil. The molecular data confirm the taxonomic complexity of the genus, as individuals morphologically identified as E. virescens and E. trilineata shared the same haplotype (H52). Furthermore, the results of the species delimitation tests suggest that specimens morphologically identified as E. virescens belong to the species E. trilineata. In addition, samples morphologically identified as E. correntes may correspond to more than one Operational Taxonomic Units (OTUs). Furthermore, the intraspecific Kimura-2-parameter (K2P) distances within the different studied populations are significant. This study has contributed valuable information about genetic diversity in Eigenmannia, emphasizing the importance of using integrative analyses to resolve taxonomic conflicts within the group. It also supports biogeographical studies and assists in biodiversity conservation efforts.

Factors affecting the transferability of bioindicators based on stream fish assemblages.

The development of multimetric indices (MMIs) to measure the biotic condition of aquatic habitats is based on metrics derived from biological assemblages. Considering fish assemblages, the inconsistencies in metrics responses outside of the places where they were developed limit MMI transferability and applicability to other locations, requiring local calibration. The factors behind the low transferability of these MMIs are still poorly understood. We investigated how environmental dissimilarity and spatial distance influence the transferability of metrics generated from local stream fish assemblages to other regions. We also tested whether functional and taxonomic metrics respond differently to the spatial distance. We used data from 239 fish assemblages from streams distributed across a Brazilian, the upper Parana basin and characterized each site according to the level of anthropogenic disturbance at the landscape scale using an Anthropogenic Pressure Index (API). We divided the upper Parana basin into sub-basins and used two of them to create template response models of the metrics in relation to the API. We used these response models to predict the responses outside the template sub-basins. Our response variable representing a metric of transferability was the absolute difference between metric's predicted and observed value for each site (prediction error). We thus modeled the prediction error in relation to the predictor variables that were i) the environmental dissimilarity between each site with the average of the sites from template sub-basins (climatic, topographic and soil type variables) and ii) the spatial distance (overland and watercourse distance) between each site and the center of the template sub-basin. We found that errors in metric predictions were associated with both environmental dissimilarity and spatial distance. Furthermore, functional and taxonomic metrics responded equally to spatial distance. These results indicate the need for local calibration of metrics when developing MMIs, especially if the protocols already available come from distant and environmentally dissimilar places.

Reproductive behaviour, cutaneous morphology, and skin secretion analysis in the anuran Dermatonotus muelleri.

Despite the common poison and mucous glands, some amphibian groups have differentiated glands associated with reproduction and usually present on the male ventral surface. Known as breeding glands or sexually dimorphic skin glands (SDSGs), they are related to intraspecific chemical communication during mating. Until recently, reproduction associated with skin glands was recognized only in salamanders and caecilians and remained unexplored among anurans. The Brazilian microhylid Dermatonotus muelleri (Muller's termite frog) is known for its very toxic skin secretion. Despite the slippery body, the male adheres to the female back during reproduction, as they have differentiated ventral glands. In this paper, we have gathered data proposing an integrative approach correlated with the species' biology and biochemical properties of their skin secretions. Furthermore, we suggest that the adhesion phenomenon is related to arm shortening and rounded body that make amplexus inefficient, although constituting important adaptive factors to life underground.

Stream fish metacommunity organisation across a Neotropical ecoregion: The role of environment, anthropogenic impact and dispersal-based processes.

Understanding how assemblages are structured in space and the factors promoting their distributions is one of the main goals in Ecology, however, studies regarding the distribution of organisms at larger scales remain biased towards terrestrial groups. We attempt to understand if the structure of stream fish metacommunities across a Neotropical ecoregion (Upper Paraná-drainage area of 820,000 km2) are affected by environmental variables, describing natural environmental gradient, anthropogenic impacts and spatial predictors. For this, we obtained 586 sampling points of fish assemblages in the ecoregion and data on environmental and spatial predictors that potentially affect fish assemblages. We calculated the local beta diversity (Local Contribution to Beta Diversity, LCBD) and alpha diversity from the species list, to be used as response variables in the partial regression models, while the anthropogenic impacts, environmental gradient and spatial factors were used as predictors. We found a high total beta diversity for the ecoregion (0.41) where the greatest values for each site sampled were located at the edges of the ecoregion, while richer communities were found more centrally. All sets of predictors explained the LCBD and alpha diversity, but the most important was dispersal variables, followed by the natural environmental gradient and anthropogenic impact. However, we found an increase in the models' prediction power through the shared effect. Results suggest that environmental filters (i.e. environmental variables such as climate, hydrology and anthropogenic impact) and dispersal limitation together shape fish assemblages of the Upper Paraná ecoregion, showing the importance of using multiple sets of predictors to understand the processes structuring biodiversity distribution.

Reproductive behaviour, cutaneous morphology, and skin secretion analysis in the anuran Dermatonotus muelleri

Despite the common poison and mucous glands, some amphibian groups have differentiated glands associated with reproduction and usually present on the male ventral surface. Known as breeding glands or sexually dimorphic skin glands (SDSGs), they are related to intraspecific chemical communication during mating. Until recently, reproduction associated with skin glands was recognized only in salamanders and caecilians and remained unexplored among anurans. The Brazilian microhylid Dermatonotus muelleri (Muller's termite frog) is known for its very toxic skin secretion. Despite the slippery body, the male adheres to the female back during reproduction, as they have differentiated ventral glands. In this paper, we have gathered data proposing an integrative approach correlated with the species' biology and biochemical properties of their skin secretions. Furthermore, we suggest that the adhesion phenomenon is related to arm shortening and rounded body that make amplexus inefficient, although constituting important adaptive factors to life underground.

Life history traits of parental care in Crenicichla lepidota (Cichliformes, Geophagini) in the upper Paraguay River basin, Brazil

During focal observations carried out in the Olho dÁgua River, upper Paraguay River basin, Brazil, we registered the defensive behaviour of one pair of Crenicichla lepidota attempting to protect their offspring from conspecific and non-specific predators. Adults exhibited substrate-guarding behaviour and displayed primary and secondary anti-predation mechanisms. The primary mechanisms (e.g., fin flicking and flaring, gill extending) were ineffective against conspecific predators or against other species. Secondary mechanisms included charging would-be predators of the offspring, and this tactic was successful against non-specifics. This record confirms, in the wild, agonistic behaviour as an effective secondary defence mechanism used in parental care in Crenicichla lepidota.(AU)

Life history traits of parental care in Crenicichla lepidota (Cichliformes, Geophagini) in the upper Paraguay River basin, Brazil

During focal observations carried out in the Olho d’Água River, upper Paraguay River basin, Brazil, we registered the defensive behaviour of one pair of Crenicichla lepidota attempting to protect their offspring from conspecific and non-specific predators. Adults exhibited substrate-guarding behaviour and displayed primary and secondary anti-predation mechanisms. The primary mechanisms (e.g., fin flicking and flaring, gill extending) were ineffective against conspecific predators or against other species. Secondary mechanisms included charging would-be predators of the offspring, and this tactic was successful against non-specifics. This record confirms, in the wild, agonistic behaviour as an effective secondary defence mechanism used in parental care in Crenicichla lepidota.

Life history traits of parental care in Crenicichla lepidota (Cichliformes, Geophagini) in the upper Paraguay River basin, Brazil

Abstract During focal observations carried out in the Olho dÁgua River, upper Paraguay River basin, Brazil, we registered the defensive behaviour of one pair of Crenicichla lepidota attempting to protect their offspring from conspecific and non-specific predators. Adults exhibited substrate-guarding behaviour and displayed primary and secondary anti-predation mechanisms. The primary mechanisms (e.g., fin flicking and flaring, gill extending) were ineffective against conspecific predators or against other species. Secondary mechanisms included charging would-be predators of the offspring, and this tactic was successful against non-specifics. This record confirms, in the wild, agonistic behaviour as an effective secondary defence mechanism used in parental care in Crenicichla lepidota.

Stream fish from recently deforested basins in the Meridional Amazon, Mato Grosso, Brazil / Peixes de riachos de bacias recentemente desmatadas na Amazônia Meridional, Mato Grosso, Brasil

Abstract: The replacement of tropical forests to production systems is one of the leading causes of riverine ecosystem alterations. However, current assemblages' composition may also result from the time since these transformations have begun. Therefore, the knowledge of diversified historical scenarios can facilitate the accomplishment of actions that involve the aquatic environments recovery. In this study, an inventory of stream fish was carried out in basins whose deforestation was intensified in the last 20 years, to compose a baseline for ecological and taxonomic studies. The habitat, physical and chemical variables, and the fish assemblages from 60 streams in the northwest region of the state of Mato Grosso, in the Aripuanã and Juruena river basins, were sampled with standardized procedures. For a total of 130 species, a numerical predominance of small-sized Characidae and great rarity were registered, with 50 species represented by less than ten individuals and 19 singletons. Approximately 15% of the sampled taxa were identified only at the generic level, and for several taxa, more detailed taxonomic and molecular studies are required in order to achieve satisfactory identifications. None threatened species were so far reported. On the other hand, two specimens of non-native species were sampled. Although habitat quality is higher in forested streams, no differences in the species richness were registered when compared to the pasture with riparian forest streams or to more deforested streams. However, abundance was greater in these last two streams groups as a result of small-sized characins dominance.

Resumo: A substituição de florestas tropicais por sistemas de produção representa uma das principais fontes de alteração nos ecossistemas de riachos. Contudo, a composição atual das assembleias também depende do tempo decorrente desde o início dessas transformações e, desta forma, o conhecimento de cenários históricos variados pode facilitar a realização de ações que envolvam a recuperação de ambientes aquáticos. Neste estudo, foi realizado o inventário dos peixes de riachos em bacias cujo desmatamento foi intensificado nos últimos 20 anos, para compor uma linha de base que possa ser usada em estudos ecológicos e taxonômicos. Foram amostradas as variáveis do hábitat, físicas e químicas e os peixes de 60 riachos da região noroeste do estado de Mato Grosso, nas bacias dos rios Aripuanã e Juruena. No total, 130 espécies foram registradas, com predominância numérica de pequenos caracídeos e grande número de espécies raras, sendo 50 espécies representadas por menos que dez indivíduos e 19 por apenas um indivíduo. Aproximadamente 15% dos táxons amostrados foram identificados somente no nível genérico e vários precisam de estudos taxonômicos e moleculares mais detalhados para alcançar identificações satisfatórias. As espécies não-nativas foram representadas por dois exemplares e nenhuma espécie sabidamente ameaçada foi registrada. Embora a qualidade do hábitat seja superior nos riachos florestados, não houve diferenças na riqueza das assembleias quando comparada aos riachos de microbacias de pastagem, porém com faixa ripária florestada, ou com maior desmatamento. Contudo, a abundância foi maior nesses dois grupos de riachos, como resultado da dominância de caracídeos de pequeno porte.

Ichthyofauna of the "Cachoeira de São Roberto" and fishes of lower Preto River, upper Paraná River basin, Brazil / Ictiofauna da Cachoeira de São Roberto e peixes do baixo rio Preto, bacia do alto rio Paraná, Brasil

Abstract Rheophilic environments typically houses fish species with specific ecological requirements. Thus, the suppression of these environments can lead to damaging impacts to local and regional fauna. In this work the ichthyofauna of the “Cachoeira de São Roberto” was inventoried, with a historical review of fish collected in the lower Preto River basin. The sampling sites included two reaches (named R1 and R2): R1 in the “Cachoeira de São Roberto” and R2 refers to two km upstream. The fishes were sampled bimonthly during one year (April 2013 to February 2014) using small and dip nets. Voucher specimens were catalogued in the Fish Collection of “Departamento de Zoologia e Botânica do Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista ‘Júlio de Mesquita Filho’, câmpus de São José do Rio Preto, SPˮ (DZSJRP). Historical records from lower Preto River basin were composed by fish species sampled downstream of spillway of the dam in the municipality of São José do Rio Preto, SP, using the database of fish collection of DZSJRP. The ichthyofauna of the sampled reaches was composed by 53 species, distributed in 16 families and seven orders. The greatest richness was found in the upstream site (R2) with the presence of Aphyocheirodon hemigrammus and Myleus tiete, two Brazilian threatened fish species. Chao index suggested the occurrence of 64 species for the inventoried reaches. Considering all portion of lower Preto River basin, including historical records, 69 species were found, four of these species have not described yet. The present study highlights the importance of inventories in rheophilic environments, which usually includes sensitive, threatened, and species with restricted distribution. Besides that, inventories can provide technical data to support decisions about potential environmental impacts helping with the management and conservation of fish fauna.

Resumo Ambientes reofílicos normalmente abrigam espécies de peixes com exigências ecológicas. Assim, a supressão desses ambientes pode levar a impactos danosos à fauna local e regional. Neste trabalho inventariou-se a ictiofauna da Cachoeira de São Roberto, com uma revisão histórica dos peixes coletados na bacia do baixo rio Preto. Os locais amostrados incluíram dois trechos (nomeados R1 e R2): R1 na área da Cachoeira de São Roberto e R2, dois km a montante de R1. As coletas ocorreram bimestralmente durante um ano (abril de 2013 a fevereiro de 2014), utilizando puçá e arrasto. Os peixes coligidos foram depositados na Coleção de Peixes do Departamento de Zoologia e Botânica do Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filhoˮ, câmpus de São José do Rio Preto, SP (DZSJRP). Registros históricos da bacia do baixo rio Preto foram representados pelas espécies de peixes coletadas a jusante do vertedouro da represa municipal de São José do Rio Preto, SP depositados na coleção DZSJRP. A ictiofauna nos trechos inventariados (R1 e R2) foi representada por 53 espécies, distribuídas em 16 famílias e sete ordens. A maior riqueza foi encontrada no R2, com registro de Aphyocheirodon hemigrammus e Myleus tiete, duas espécies da ictiofauna brasileira ameaçadas de extinção. Estimativas de diversidade (Chao index) sugeriram a ocorrência de 64 espécies nos trechos inventariados. Considerando toda porção da bacia do baixo rio Preto, incluindo os registros históricos, registrou-se 69 espécies, quatro delas ainda não descritas formalmente. O presente estudo ressalta a importância de inventários em áreas reofílicas, que normalmente inclui espécies sensíveis, ameaçadas e com distribuição restrita. Além disso, inventários podem fornecer dados técnicos para subsidiar decisões sobre impactos ambientais auxiliando a gestão e conservação da fauna de peixes.

Identification key for fishes from coastal streams of the Atlantic forest of southeastern Brazil / Chave de identificação para os peixes de riachos costeiros da Mata Atlântica, sudeste do Brasil

Abstract In recent decades, current knowledge about fish from Neotropical streams has greatly increased, but is still deficient. Here we present an identification key for fishes from coastal freshwater streams from a large conservation area of Atlantic rainforest of southeastern Brazil, including 39 species. Considering that most of these species (61.2%) are endemic to the coastal streams, this identification key will be useful not only for the species recognition of the sampled area, but also for the surrounding coastal region.

Resumo Nas últimas décadas, o conhecimento acerca dos peixes de riachos neotropicais aumentou consideravelmente, mas apesar disso ainda é deficiente. Apresentamos aqui uma chave de identificação para as 39 espécies de peixes de uma grande unidade de conservação da Mata Atlântica do sudeste do Brasil. Considerando que a maioria destas espécies (61,2%) são endêmicas dos riachos costeiros, esta chave de identificação será útil não só para o reconhecimento de espécies da área amostrada, mas também da região costeira do entorno.

Contribution of different mesohabitats to the maintenance of fish richness and diversity in the lower Preto River / Contribuição de diferentes meso-hábitats para a manutenção da riqueza e diversidade de peixes no baixo rio Preto

The presence of different mesohabitats in freshwater systems can support higher local and regional fish richness. Thus, their suppression by dam-building represents a real threat to aquatic biodiversity. Our aims were: (1) to survey the fish fauna in two different mesohabitats in lower Preto River: a riffle indirectly threatened by dam-building and a run with different physical structure; and (2) to analyze and compare the fish community structure in these different mesohabitats. Six samplings were made during one year in two reaches (R1 and R2). We conducted a one way ANOSIM to assess the differences in fish community structure between R1 and R2. Fifty-three species were recorded, with the occurrence of Aphyocheirodon hemigrammus and Myleus tiete, two Brazilian threatened species. The highest richness was observed in R2. Nevertheless, diversity and evenness were significantly higher in R1. Rheophilic species were more common and restricted to R1 and species typical of lentic environments were predominant in R2. Fish community structure was different between R1 and R2 (R = 1, p = 0.02). Our results demonstrated that mesohabitats mosaic through rivers can contribute to the maintenance of a diverse fish assemblage.(AU)

A presença de diferentes meso-hábitats em sistemas de água doce pode suportar alta riqueza local e regional de peixes. Assim, sua supressão pela construção de reservatórios representa uma ameaça real para a biodiversidade aquática. Nossos objetivos foram: (1) inventariar a ictiofauna de duas áreas na porção inferior do rio Preto, uma corredeira indiretamente ameaçada pela construção de um reservatório e um corredor com estrutura física diferente; e (2) verificar se esses meso-hábitats apresentam distintas estruturas de comunidade de peixes. Seis amostragens foram conduzidas durante um ano em dois trechos (R1 e R2). Uma ANOSIM one way foi realizada para investigar se R1 e R2 apresentavam estruturas de comunidade diferentes. Foram coletadas 53 espécies, com ocorrência de Aphyocheirodon hemigrammus e Myleus tiete, duas espécies brasileiras ameaçadas. A maior riqueza foi registrada em R2. Entretanto, diversidade e equabilidade foram significativamente maiores em R1. Espécies reofílicas foram mais comuns em R1, enquanto espécies de ambientes lênticos foram mais abundantes em R2. R1 e R2 apresentaram diferenças significativas na estrutura da comunidade (R = 1, p = 0,02). Nossos resultados demonstraram que um mosaico de meso-hábitats ao longo de ambientes aquáticos pode contribuir para a manutenção da diversidade das assembleias de peixes.(AU)

Contribution of different mesohabitats to the maintenance of fish richness and diversity in the lower Preto River / Contribuição de diferentes meso-hábitats para a manutenção da riqueza e diversidade de peixes no baixo rio Preto

The presence of different mesohabitats in freshwater systems can support higher local and regional fish richness. Thus, their suppression by dam-building represents a real threat to aquatic biodiversity. Our aims were: (1) to survey the fish fauna in two different mesohabitats in lower Preto River: a riffle indirectly threatened by dam -building and a run with different physical structure; and (2) to analyze and compare the fish community structure in these different mesohabitats. Six samplings were made during one year in two reaches (R1 and R2). We conducted a 'one way' ANOSIM to assess the differences in fish community structure between R1 and R2. Fifty-three species were recorded, with the occurrence of Aphyocheirodon hemigrammus and Myleus tiete, two Brazilian threatened species. The highest richness was observed in R2. Nevertheless, diversity and evenness were significantly higher in R1. Rheophilic species were more common and restricted to R1 and species typical of lentic environments were predominant in R2. Fish community structure was different between R1 and R2 (R = 1, p = 0.02). Our results demonstrated that mesohabitats mosaic through rivers can contribute to the maintenance of a diverse fish assemblage.

A presença de diferentes meso-hábitats em sistemas de água doce pode suportar alta riqueza local e regional de peixes. Assim, sua supressão pela construção de reservatórios representa uma ameaça real para a biodiversidade aquática. Nossos objetivos foram: (1) inventariar a ictiofauna de duas áreas na porção inferior do rio Preto, uma corredeira indiretamente ameaçada pela construção de um reservatório e um corredor com estrutura física diferente; e (2) verificar se esses meso-hábitats apresentam distintas estruturas de comunidade de peixes. Seis amostragens foram conduzidas durante um ano em dois trechos (R1 e R2). Uma ANOSIM one way foi realizada para investigar se R1 e R2 apresentavam estruturas de comunidade diferentes. Foram coletadas 53 espécies, com ocorrência de Aphyocheirodon hemigrammus e Myleus tiete, duas espécies brasileiras ameaçadas. A maior riqueza foi registrada em R2. Entretanto, diversidade e equabilidade foram significativamente maiores em R1. Espécies reofílicas foram mais comuns em R1, enquanto espécies de ambientes lênticos foram mais abundantes em R2. R1 e R2 apresentaram diferenças significativas na estrutura da comunidade (R = 1, p = 0,02). Nossos resultados demonstraram que um mosaico de meso-hábitats ao longo de ambientes aquáticos pode contribuir para a manutenção da diversidade das assembleias de peixes.

Fish assemblages in stream stretches occupied by cattail (Typhaceae, Angiospermae) stands in Southeast Brazil

Macrophytes are a major component of lentic and lotic aquatic ecosystems. As consequences of environmental degradation, species of cattail (genus Typha) may become dominant along streams. The purpose of this study was to investigate the structure and feeding of fish assemblages in stream stretches under influence of Typha sp., also addressing the influences of temporal variation on composition, abundance, biomass, diversity, species richness, and feeding of fish. Six streams (labelled S1-S6) in the upper rio Turvo basin, southeast Brazil, with dense stands of Typha sp. in the instream and riparian habitat, were studied in six campaigns during three central months in both of the dry and wet periods, by using a standardized collection effort. Thirty-seven fish species were registered, totaling 4,228 individuals and 3.9 kg of biomass. Abundance, biomass, diversity, and species richness was higher in the wet period, but only the temporal variation in the species richness revealed to be statistically significant. Cluster analyses with composition and abundance showed little temporal similarity, but indicated two groups of streams (S1-S2-S5 and S3-S4-S6), that were corroborated along the axis 1 of the ordination analysis. Resident species was represented by six species, most of them considered tolerant and generalists. Chironomidae aquatic larvae and detritus were the most important items in the fish diet. These results suggest that the fish populations are opportunistic in exploring stream stretches occupied by cattail.(AU)

Macrófitas são um importante componente de ecossistemas aquáticos lóticos e lênticos. Como consequências da degradação ambiental, espécies de taboas (gênero Typha) podem se tornar dominantes em riachos. O objetivo do presente estudo foi investigar a estrutura e alimentação de uma comunidade de peixes em trechos de riachos com influência de Typha sp., bem como a variação temporal na composição, abundância, biomassa, diversidade, riqueza de espécies e alimentação da ictiofauna. Seis riachos (nomeados S1-S6) na bacia do alto rio Turvo, sudeste do Brasil, com densos bancos de Typha sp. no habitat interno e ripário, foram estudados em seis campanhas durante os três meses centrais dos períodos seco e chuvoso, por meio de um esforço padronizado de coleta. Trinta e sete espécies foram registradas, totalizando 4.228 indivíduos e 3,9 kg de biomassa. Abundância, biomassa, diversidade e riqueza de espécies foram maiores no período chuvoso, mas somente as diferenças temporais na riqueza de espécies se mostraram estatisticamente significativas. As análises de agrupamentos com a composição e abundância mostraram baixa similaridade temporal, mas indicaram dois grupos de riachos (S1-S2-S5 e S3-S4-S6), o que foi corroborado ao longo do eixo 1 da análise de ordenação. A fauna de peixes residente foi representada por seis espécies, a maioria tolerante e com hábitos generalistas. Larvas aquáticas de Chironomidae e detritos foram os itens mais importantes na dieta dos peixes. Os resultados obtidos sugerem que as populações de peixes exploram os trechos de riachos com Typha de forma oportunística.(AU)

Fish assemblages in stream stretches occupied by cattail (Typhaceae, Angiospermae) stands in Southeast Brazil

Macrophytes are a major component of lentic and lotic aquatic ecosystems. As consequences of environmental degradation, species of cattail (genus Typha) may become dominant along streams. The purpose of this study was to investigate the structure and feeding of fish assemblages in stream stretches under influence of Typha sp., also addressing the influences of temporal variation on composition, abundance, biomass, diversity, species richness, and feeding of fish. Six streams (labelled S1-S6) in the upper rio Turvo basin, southeast Brazil, with dense stands of Typha sp. in the instream and riparian habitat, were studied in six campaigns during three central months in both of the dry and wet periods, by using a standardized collection effort. Thirty-seven fish species were registered, totaling 4,228 individuals and 3.9 kg of biomass. Abundance, biomass, diversity, and species richness was higher in the wet period, but only the temporal variation in the species richness revealed to be statistically significant. Cluster analyses with composition and abundance showed little temporal similarity, but indicated two groups of streams (S1-S2-S5 and S3-S4-S6), that were corroborated along the axis 1 of the ordination analysis. Resident species was represented by six species, most of them considered tolerant and generalists. Chironomidae aquatic larvae and detritus were the most important items in the fish diet. These results suggest that the fish populations are opportunistic in exploring stream stretches occupied by cattail.

Macrófitas são um importante componente de ecossistemas aquáticos lóticos e lênticos. Como consequências da degradação ambiental, espécies de taboas (gênero Typha) podem se tornar dominantes em riachos. O objetivo do presente estudo foi investigar a estrutura e alimentação de uma comunidade de peixes em trechos de riachos com influência de Typha sp., bem como a variação temporal na composição, abundância, biomassa, diversidade, riqueza de espécies e alimentação da ictiofauna. Seis riachos (nomeados S1-S6) na bacia do alto rio Turvo, sudeste do Brasil, com densos bancos de Typha sp. no habitat interno e ripário, foram estudados em seis campanhas durante os três meses centrais dos períodos seco e chuvoso, por meio de um esforço padronizado de coleta. Trinta e sete espécies foram registradas, totalizando 4.228 indivíduos e 3,9 kg de biomassa. Abundância, biomassa, diversidade e riqueza de espécies foram maiores no período chuvoso, mas somente as diferenças temporais na riqueza de espécies se mostraram estatisticamente significativas. As análises de agrupamentos com a composição e abundância mostraram baixa similaridade temporal, mas indicaram dois grupos de riachos (S1-S2-S5 e S3-S4-S6), o que foi corroborado ao longo do eixo 1 da análise de ordenação. A fauna de peixes residente foi representada por seis espécies, a maioria tolerante e com hábitos generalistas. Larvas aquáticas de Chironomidae e detritos foram os itens mais importantes na dieta dos peixes. Os resultados obtidos sugerem que as populações de peixes exploram os trechos de riachos com Typha de forma oportunística.

Feeding association between benthic and nektonic Neotropical stream fishes

Following behaviour among Neotropical stream fishes have been scarcely reported. This type of feeding association was observed in a small stream in the upper rio Paraná system between the catfish, Aspidoras fuscoguttatus, acting as a nuclear species, and Knodus moenkhausii, Poecilia reticulata, and Astyanax altiparanae as follower species. Aspidoras fuscoguttatus individuals dug in the bottom during feeding, causing sediment suspension. Their followers picked food items in the "cloud" of suspended particles. Food items of sediment are no longer consumed by the catfish when in suspension, but are still available for K. moenkhausii, P. reticulata and A. altiparanae. Following behaviour is an alternative feeding tactic for these species, which reinforces the general idea of behavioural plasticity among follower species.(AU)

A interação nuclear-seguidor tem sido raramente registrada entre peixes de riachos Neotropicais. Este tipo de associação foi observada em um riacho de cabeceira, no sistema do Alto rio Paraná envolvendo o cascudinho, Aspidoras fuscoguttatus, como espécie nuclear, e Knodus moenkhausii, Poecilia reticulata e Astyanax altiparanae como seus seguidores. Indivíduos de Aspidoras fuscoguttatus revolveram o substrato durante alimentação, promovendo a suspensão de sedimento. Os seguidores, por sua vez, movimentaram-se pela "nuvem" de partículas em suspensão, capturando itens alimentares. As particulas alimentares em suspensão parecem não ser utilizadas pelo cascudinho, mas tornam-se disponíveis para K. moenkhausii, P. reticulata e A. altiparanae. O comportamento de seguidor representa uma tática alimentar alternativa para estas espécies, reforçando a idéia geral de plasticidade comportamental entre as espécies seguidoras.(AU)

Feeding association between benthic and nektonic Neotropical stream fishes

Following behaviour among Neotropical stream fishes have been scarcely reported. This type of feeding association was observed in a small stream in the upper rio Paraná system between the catfish, Aspidoras fuscoguttatus, acting as a nuclear species, and Knodus moenkhausii, Poecilia reticulata, and Astyanax altiparanae as follower species. Aspidoras fuscoguttatus individuals dug in the bottom during feeding, causing sediment suspension. Their followers picked food items in the "cloud" of suspended particles. Food items of sediment are no longer consumed by the catfish when in suspension, but are still available for K. moenkhausii, P. reticulata and A. altiparanae. Following behaviour is an alternative feeding tactic for these species, which reinforces the general idea of behavioural plasticity among follower species.

A interação nuclear-seguidor tem sido raramente registrada entre peixes de riachos Neotropicais. Este tipo de associação foi observada em um riacho de cabeceira, no sistema do Alto rio Paraná envolvendo o cascudinho, Aspidoras fuscoguttatus, como espécie nuclear, e Knodus moenkhausii, Poecilia reticulata e Astyanax altiparanae como seus seguidores. Indivíduos de Aspidoras fuscoguttatus revolveram o substrato durante alimentação, promovendo a suspensão de sedimento. Os seguidores, por sua vez, movimentaram-se pela "nuvem" de partículas em suspensão, capturando itens alimentares. As particulas alimentares em suspensão parecem não ser utilizadas pelo cascudinho, mas tornam-se disponíveis para K. moenkhausii, P. reticulata e A. altiparanae. O comportamento de seguidor representa uma tática alimentar alternativa para estas espécies, reforçando a idéia geral de plasticidade comportamental entre as espécies seguidoras.

Ichthyofauna of the rio Itatinga in the Parque das Neblinas, Bertioga, São Paulo State: composition and biogeography / Ictiofauna do rio Itatinga no Parque das Neblinas, Bertioga, Estado de São Paulo: composição e biogeografia

Little is known about the ichthyofauna from South American coastal plain, specially concerning the Mata Atlântica (Atlantic Forest) rivers and streams, as there are regions little explored which may have non-described or rare species. An example is the Parque das Neblinas, a Natural Patrimony Private Reserve (RPPN) in the Bertioga municipality, São Paulo state, where no ichthyofaunal study had been done before. The park's hydrography is made up by the rio Itatinga with its various tributary streams, which flow into the Itapanhaú river basin. Nine sites were sampled using sieves, seines and gill nets; 1,086 specimens of seven species, three orders and five families were captured. The most representative species were Astyanax paranae, Phalloceros caudimaculatus, and Coptobrycon bilineatus. Four of those collected are on the Brazilian list of endangered species: Coptobrycon bilineatus, Glandulocauda melanogenys, Pseudotocinclus tietensis, and Taunaya bifasciata; one, Trichomycterus sp., has an undefined taxonomic status, possibly being a non-described species. The richness of species found in the upper part of the rio Itatinga is typical of the Mata Atlântica headwaters, which can also be due to headwater capture of part of the upper rio Tietê. This is the first record of Coptobrycon bilineatus in the coastal drainage, hitherto restricted to the upper Paraná river system. The distribution of Taunaya bifasciata and Pseudotocinclus tietensis is also extended. The fauna sharing found here confirms the biogeographical common history hypothesis among southeastern coastal and Brazilian Shield drainages.

A ictiofauna da planície costeira do leste da América do Sul é pouco conhecida, especialmente em relação aos rios e riachos da Mata Atlântica, existindo regiões pouco exploradas, que podem abrigar espécies raras ou não descritas para a ciência. Exemplo dessa situação é o Parque das Neblinas, uma Reserva Particular do Patrimônio Natural (RPPN) no município de Bertioga, estado de São Paulo, onde nenhum levantamento ictiofaunístico havia sido feito até o presente. A hidrografia do Parque é formada pelo rio Itatinga e seus vários riachos afluentes, que deságuam na bacia do rio Itapanhaú. Foram amostrados nove pontos utilizando peneiras de arroz, redes de arrasto e redes de espera, que resultaram na captura de 1.086 exemplares de peixes, de sete espécies, três ordens e cinco famílias. As espécies mais representativas foram Astyanax paranae, Phalloceros caudimaculatus e Coptobrycon bilineatus. Quatro das espécies coletadas estão na lista de espécies brasileiras ameaçadas de extinção: Coptobrycon bilineatus, Glandulocauda melanogenys, Pseudotocinclus tietensis e Taunaya bifasciata. Uma das espécies, Trichomycterus sp., apresenta status taxonômico indefinido, podendo se tratar de uma espécie não descrita. A riqueza de espécies encontrada nessa porção do alto curso do rio Itatinga é típica de riachos de cabeceira de Mata Atlântica, podendo também ser conseqüência de fenômeno de captura de cabeceiras de porção do Alto rio Tietê. O encontro de Coptobrycon bilineatus consiste no primeiro registro para drenagens litorâneas, antes restrita ao sistema do Alto rio Paraná. Amplia-se também a distribuição de Taunaya bifasciata e Pseudotocinclus tietensis. O compartilhamento de fauna aqui apresentado corrobora a hipótese de história biogeográfica comum entre porções das drenagens costeiras do sudeste e do escudo brasileiro.