The main channel and river confluences as spawning sites for migratory fishes in the middle Uruguay River

Evidence indicates that migratory fish reproduce in the middle Uruguay River, but the location of spawning sites remains unknown. To identify spawning sites in the basin, fish eggs and larvae were sampled monthly between October 2016 and January 2017. The sampling was carried out in three sections along the middle Uruguay River, covering two environments: the main channel and the mouth of tributaries (Comandaí, Ijuí, and Piratinim rivers). A total of 11,519 eggs and 3,211 larvae were captured, belonged to ten migratory species. Eggs and larvae of migratory fishes, were widely distributed, with predominance of segmented eggs, and larvae in yolk-sac and pre-flexion stages, with higher densities near the confluence with the Piratinim River. Larvae assemblages showed spatial variation, indicating that spawning sites differ among migratory species. This study provides new information about fish reproduction in the middle Uruguay River, revealing that migratory species spawn in different localities along the main channel and tributaries. This region may function as a critical site for fish reproduction, although it is currently threatened by the risk of hydropower expansion, emphasizing the need for measures that preserve their environmental conditions, hydrological connectivity and ecological functions.(AU)

Evidências indicam que os peixes migradores se reproduzem no médio rio Uruguai, mas a localização dos locais de desova ainda permanece desconhecida. Para identificar estes locais, foram realizadas mensalmente entre outubro de 2016 e janeiro de 2017, amostragens de ovos e larvas de peixes em três seções ao longo do médio rio Uruguai, cobrindo dois ambientes: o canal principal e a foz dos afluentes (rios Comandaí, Ijuí e Piratinim). Foram capturados 11.519 ovos e 3.211 larvas, pertencentes a dez espécies migradoras. Ovos e larvas de peixes migradores, foram amplamente distribuídos, com predomínio de ovos segmentados e larvas em estágios de larval-vitelino e pré-flexão, com maiores densidades próximo à confluência com o rio Piratinim. As assembleias de larvas mostraram variação espacial, indicando que os locais de desova diferem entre as espécies migradoras. Este estudo fornece novas informações sobre a reprodução de peixes no médio rio Uruguai, revelando que espécies migradoras desovam em diferentes localidades ao longo do canal principal e afluentes. Esta região pode funcionar como um local crítico para a reprodução de peixes, embora atualmente esteja ameaçada pelo risco de expansão da energia hidrelétrica, enfatizando a necessidade de medidas que preservem suas condições ambientais, conectividade hidrológica e funções ecológicas.(AU)

Spatial partitioning between juveniles and adults of the freshwater anomuran crab Aegla parana (Crustacea Aeglidae) from southern Brazil

In order to understand the role of lower order tributaries in the population structuring of the freshwater anomuran crab Aegla parana Schmitt, 1942, a study on the distribution of demographic categories was carried out along Negro River and in its tributary Totó River that belong to Upper Iguaçu Basin, southern Brazil. Two collection points were established along the main channel of Negro River, in a 7.00 km long stretch, and three points in the entire creek Totó River with 6.61 km long. The animals were captured with Surber net and baited traps and had the carapace length (CL) measured. A total 146 crabs were obtained from Negro River and 361 from Totó River, performing 507 analyzed aeglids. From the point 1 of Negro River, males measured 27.68 ± 12.68 mm CL and females 18.98 ± 5.88 mm CL; from point 2 of the same river, the values were 24.45 ± 13.70 mm CL and 27 ± 8.50 mm CL, respectively. There was a positive and direct relationship between the mean CL of the aeglids from Totó River and the distance of the collection points from its source. Males: point 1 (source of the creek): 7.90 ± 1.23 mm CL; point 2: 9.55 ± 3.06 mm CL; point 3: 9.91 ± 2.62 mm CL. Females: point 1 (source): 6.68 ± 1.70 mm CL; point 2: 9.01 ± 1.94 mm CL; point 3: 10.49 ± 2.57 mm CL. The sexually immature aeglids are distributed mainly in the lower order tributary (= Totó River), and the mature ones in the main channel of Negro River, indicating that this population perform ontogenetic migrations from tributary to the main river. The spatial partition can be explained under three aspects that are quite contrasting between Negro River and Totó River: 1. substrate architecture; 2. depth of the water column and 3. quality of available food.(AU)

A new dwarf armored catfish Pareiorhaphis (Loricariidae: Hypoptopomatinae) from the Uruguai River basin, Southern Brazil

A new, very distinctive species of Pareiorhaphis is described from the rio Uruguai basin, in Rio Grande do Sul State, southern Brazil. Pareiorhaphis pumila, new species, is a small bodied hypoptopomatine catfish with a maximum standard length barely reaching 50 mm. The specimens were captured from rock-bottomed habitats in various localities in the rio Ijuí basin. Despite occurring in rock-bottomed fast-flowing headwater stream tributaries as the other species of Pareiorhaphis, this is the first species collected also in the main channel of the middle stretch of a large tributary to the rio Uruguai. The new species is promptly diagnosed from all its congeners by the reduced number of anal-fin branched rays, possession of well-developed dorsal-fin spinelet, comparatively lower number of plates in median lateral series, and low number of teeth in each dentary. In addition, osteological features related to the caudal skeleton are also useful to distinguish the new species from most congeners.

Uma nova e distinta espécie de Pareiorhaphis é descrita da bacia do rio Uruguai, no estado do Rio Grande do Sul, sul do Brasil. A nova espécie é um cascudo hypoptopomatíneo de pequeno tamanho, com comprimento padrão máximo inferior a 50 mm. Os espécimes foram capturados em habitats de fundo rochoso em várias localidades da bacia do rio Ijuí. Apesar de ocorrer em córregos de cabeceira de fluxo rápido com fundo rochoso como as demais espécies de Pareiorhaphis, esta é a primeira espécie coletada também no canal principal do trecho médio de um grande afluente do rio Uruguai. A nova espécie é prontamente diagnosticada de todos os seus congêneres pelo número reduzido de raios ramificados da nadadeira anal, presença de spinelet da nadadeira dorsal bem desenvolvido, número comparativamente menor de placas na série lateral média, e baixo número de dentes em cada dentário. Além disso, características osteológicas relacionadas ao esqueleto caudal também são úteis para distinguir a nova espécie da maioria das congêneres.

Histopathological alterations in gills, liver, kidney and muscles of Ictalurus punctatus collected from pollutes areas of river / Alterações histopatológicas em brânquias, fígado, rim e músculos de Ictalurus punctatus coletados em áreas poluídas do rio

Untreated sewage and industrial wastes from Faisalabad city are disposed to River Chenab through Chakbandi Main Drain (CMD). The present project is planned to investigate the effects of this freshwater pollution on the body of fish Ictalurus punctatus. The specimens of this fish species were collected upstream and downstream of the entrance of CMD into River Chenab. Fish gills, liver, kidney and muscles from dorsolateral regions of fish were subjected to histopathology. Farmed fish and fish from upstream areas were used as control. Fish collected from polluted experimental sites showed significant damage in selected organs. Gill tissues showed an abnormality in the form of an uplifting of the primary epithelium, fusion, vacuolation, hypertrophy, and necrosis. While liver tissues subjected to hepatocytes degeneration, necrosis, mitochondrial granular hepatocyte, and sinusoids dilation. Kidney tissues indicated increased bowmen space and constricted glomerulus and degenerated nephrons. Edema, necrosis, and atrophy were observed in muscle tissues of fish from polluted areas. Fish from the upstream area showed fused gill lamellae, inflammatory cell infiltration, hypertrophy and vacuolation in hepatocytes. Kidney tissues indicated the presence of nuclear tubular cells, destructive renal tubules, hemorrhage, and necrosis at tubular epithelium. Intra myofibril spaces were also observed in muscles. Specimens of control fish indicated no variation in gills, liver, kidney, and muscles. The present study revealed a strong correlation between the degree of tissue damage and environmental contamination. Present findings also compel global warnings to protect our water bodies and fish to rescue the human population.(AU)

O esgoto não tratado e os resíduos industriais da cidade de Faisalabad, no Paquistão, são descartados no Rio Chenab através do dreno principal de Chakbandi (CMD). O presente projeto busca investigar os efeitos dessa poluição de água doce no corpo de peixes Ictalurus punctatus. Os espécimes deste peixe foram coletados a montante e a jusante da entrada do CMD no Rio Chenab. Brânquias, fígado, rim e músculos das regiões dorsolaterais dos peixes foram submetidos à histopatologia. Peixes de criação e peixes de áreas a montante foram utilizados como controle. Peixes coletados em locais experimentais poluídos mostraram danos significativos em órgãos selecionados. Os tecidos branquiais mostraram uma anormalidade na forma de elevação do epitélio primário, fusão, vacuolação, hipertrofia e necrose. Observou-se que os tecidos hepáticos estão sujeitos a degeneração de hepatócitos, necrose, hepatócitos mitocondriais granulares e dilatação de sinusoides. Os tecidos renais indicaram aumento do espaço dos arqueiros, glomérulos contraídos e néfrons degenerados. Edema, necrose e atrofia foram observados nos tecidos musculares de peixes de áreas poluídas. Peixes da área a montante apresentaram lamelas branquiais fundidas, infiltração de células inflamatórias, hipertrofia e vacuolização em hepatócitos. Os tecidos renais indicaram a presença de células tubulares nucleares, túbulos renais destrutivos, hemorragia e necrose no epitélio tubular. Os espaços intramiofibrilas também foram observados nos músculos. Amostras de peixes controle não indicaram variação em brânquias, fígado, rim e músculos. O presente estudo revelou uma forte correlação entre o grau de dano tecidual e a contaminação ambiental. As descobertas atuais também constituem avisos globais para proteger nossos corpos d'água e peixes para resguardar a população humana.(AU)

Larvae of migratory Characiformes species in an archipelago in the Lower Amazon River

In the Amazon basin, most of the migratory Characiformes species represent an important fishing resource for local people. However, the lack of information about the main areas and periods of reproduction and the importance of certain environments for the maintenance of species may jeopardize the renewal of fish stocks. Thus, the aim was to examine the spatial and seasonal variation in the density of larvae of migratory Characiformes species in an archipelago in the Lower Amazon River and to assess the importance of this environment for the biological recruitment of the studied species. The capture of larvae was carried out in places close to restinga swamps, steep ruts,and inlet areas with a plankton net (300 μm) in monthly sampling from January to December 2013. An analysis of variance was used to verify differences in larval density between seasons and sampling months. A total of 30,997 larvae were captured and showed no significant differences in their distributions between habitats. However, a variationbetween the phases of the hydrological cycle was evident, in which the highest larval concentrations were observed during the flooding (17.72 larvae.10m-3) and the drought (1.33 larvae.10m-3). The study area has a great capacity to assist in the maintenance and renewal of regional fish stocks, as it is an important retention and nursery site for larvae of Characiformes that drift along the main channel of the Amazon River.

Larvae of migratory Characiformes species in an archipelago in the Lower Amazon River

In the Amazon basin, most of the migratory Characiformes species represent an important fishing resource for local people. However, the lack of information about the main areas and periods of reproduction and the importance of certain environments for the maintenance of species may jeopardize the renewal of fish stocks. Thus, the aim was to examine the spatial and seasonal variation in the density of larvae of migratory Characiformes species in an archipelago in the Lower Amazon River and to assess the importance of this environment for the biological recruitment of the studied species. The capture of larvae was carried out in places close to restinga swamps, steep ruts,and inlet areas with a plankton net (300 μm) in monthly sampling from January to December 2013. An analysis of variance was used to verify differences in larval density between seasons and sampling months. A total of 30,997 larvae were captured and showed no significant differences in their distributions between habitats. However, a variationbetween the phases of the hydrological cycle was evident, in which the highest larval concentrations were observed during the flooding (17.72 larvae.10m-3) and the drought (1.33 larvae.10m-3). The study area has a great capacity to assist in the maintenance and renewal of regional fish stocks, as it is an important retention and nursery site for larvae of Characiformes that drift along the main channel of the Amazon River.(AU)

The most important fishery resource in the Amazon, the migratory catfish Brachyplatystoma vaillantii (Siluriformes: Pimelodidae), is composed by an unique and genetically diverse population in the Solimões-Amazonas River System

The migratory catfish Brachyplatystoma vaillantii is one of the most important fishery resources in the Amazon. Intense capture occurs associated to its life cycle. In order to know the genetic status, we sequenced the mitochondrial DNA control region from 150 individuals of B. vaillantii, collected in five fishing landing locations, covering the length of the Solimões-Amazonas River in Brazil. Genetic diversity parameters suggest there is no genetic differentiation between the five localities. Population's expansion indicated by R 2 and Fu's Fs tests was also confirmed by the high number of unique haplotypes found. The Analyses of molecular variance indicated that nearly all variability was contained within locations (99.86%), and estimates of gene flow among B. vaillantii were high (F ST = 0.0014). These results suggest that Brachyplatystoma vaillantii forms a panmitic population along the Solimões-Amazonas River and, has greater genetic variability than other species of the Brachyplatystoma genus available so far. Although the influence of different tributaries on B. vaillantii migration patterns remains uncertain, a single population in the main channel should be consider in future policies for management of this resource. However, since the species' life cycle uses habitats in several countries, its management and conservation depend greatly of internationally joined efforts.(AU)

O bagre migrador, Brachyplatystoma vaillantii, é um dos mais importantes recursos pesqueiros da Amazônia. Intensa captura ocorre associada ao seu ciclo de vida. Para conhecer seu status genético, sequenciamos a região de controle do DNA mitocondrial de 150 indivíduos, coletados em cinco locais de desembarque pesqueiro, abrangendo toda a extensão do rio Solimões-Amazonas no Brasil. Os parâmetros de diversidade genética sugerem que não existe diferenciação genética entre as cinco localidades amostradas. A expansão populacional indicada pelos testes R 2 e Fs de Fu, também foi confirmada pelo elevado número de haplótipos únicos encontrados. A análise de variância molecular indicou que quase toda a variabilidade estava contida nas localidades (99,86%), e as estimativas de fluxo gênico desta espécie eram altas (F ST = 0,0014). Esses resultados sugerem que Brachyplatystoma vaillantii forma uma população panmítica ao longo do rio Solimões-Amazonas com maior variabilidade genética que outras espécies do gênero Brachyplatystoma disponíveis no momento. Embora a influência dos diferentes afluentes na migração de B. vaillantii permaneça incerta, em futuras políticas de gestão deste recurso deve-se considerá-lo como uma única população no canal principal. Entretanto, uma vez que seu ciclo de vida abrange habitats em vários países, seu manejo e conservação dependem muito de esforços internacionais em conjunto.(AU)

The most important fishery resource in the Amazon, the migratory catfish Brachyplatystoma vaillantii (Siluriformes: Pimelodidae), is composed by an unique and genetically diverse population in the Solimões-Amazonas River System

The migratory catfish Brachyplatystoma vaillantii is one of the most important fishery resources in the Amazon. Intense capture occurs associated to its life cycle. In order to know the genetic status, we sequenced the mitochondrial DNA control region from 150 individuals of B. vaillantii, collected in five fishing landing locations, covering the length of the Solimões-Amazonas River in Brazil. Genetic diversity parameters suggest there is no genetic differentiation between the five localities. Population's expansion indicated by R 2 and Fu's Fs tests was also confirmed by the high number of unique haplotypes found. The Analyses of molecular variance indicated that nearly all variability was contained within locations (99.86%), and estimates of gene flow among B. vaillantii were high (F ST = 0.0014). These results suggest that Brachyplatystoma vaillantii forms a panmitic population along the Solimões-Amazonas River and, has greater genetic variability than other species of the Brachyplatystoma genus available so far. Although the influence of different tributaries on B. vaillantii migration patterns remains uncertain, a single population in the main channel should be consider in future policies for management of this resource. However, since the species' life cycle uses habitats in several countries, its management and conservation depend greatly of internationally joined efforts.(AU)

O bagre migrador, Brachyplatystoma vaillantii, é um dos mais importantes recursos pesqueiros da Amazônia. Intensa captura ocorre associada ao seu ciclo de vida. Para conhecer seu status genético, sequenciamos a região de controle do DNA mitocondrial de 150 indivíduos, coletados em cinco locais de desembarque pesqueiro, abrangendo toda a extensão do rio Solimões-Amazonas no Brasil. Os parâmetros de diversidade genética sugerem que não existe diferenciação genética entre as cinco localidades amostradas. A expansão populacional indicada pelos testes R 2 e Fs de Fu, também foi confirmada pelo elevado número de haplótipos únicos encontrados. A análise de variância molecular indicou que quase toda a variabilidade estava contida nas localidades (99,86%), e as estimativas de fluxo gênico desta espécie eram altas (F ST = 0,0014). Esses resultados sugerem que Brachyplatystoma vaillantii forma uma população panmítica ao longo do rio Solimões-Amazonas com maior variabilidade genética que outras espécies do gênero Brachyplatystoma disponíveis no momento. Embora a influência dos diferentes afluentes na migração de B. vaillantii permaneça incerta, em futuras políticas de gestão deste recurso deve-se considerá-lo como uma única população no canal principal. Entretanto, uma vez que seu ciclo de vida abrange habitats em vários países, seu manejo e conservação dependem muito de esforços internacionais em conjunto.(AU)

Seasonal and longitudinal variation in fish assemblage structure along an unregulated stretch of the Middle Uruguay River

Diversity patterns and their causes remain important questions, especially for ecosystems that preserve natural conditions. This is the case of fish diversity in large Neotropical rivers. In this context, we investigated fish diversity patterns along an extensive unregulated river section (ca. 450 km) in the Middle Uruguay River Basin. Sampling was conducted seasonally between May 2017 and March 2018, at six sites (patches) with contrasting environmental conditions. We collected 3,008 individuals belonging to 90 species. Nine were migratory, which summed relevant biomass in local assemblages (20 to 60%). We observed spatial variation in assemblage structure, but weak seasonal effects. Overall, biomass was similar among sites, but richness tended to increase downstream. Migratory fishes showed opposed trends, with higher richness and biomass upstream, particularly catfishes (Siluriformes). Ordination analyses separated sites in three groups based on variations in composition and abundance, and revealed associations between these groups and specific hydro-geomorphic conditions (i.e., flow, depth, channel width and the presence of riparian vegetation). Our study revealed that fish diversity distributes heterogeneously along the main channel, where hydro-geomorphic patches select for distinct assemblages along riverine gradients.(AU)

Os padrões de diversidade e suas causas continuam sendo questões importantes, especialmente em ecossistemas que preservam condições naturais. Este é o caso da diversidade de peixes em grandes rios neotropicais. Neste contexto, investigamos padrões de diversidade de peixes ao longo de um extenso gradiente fluvial (ca. 450 km) no médio rio Uruguai. As amostragens ocorreram sazonalmente entre maio/2017 e março/2018 em seis locais com condições ambientais distintas. Coletamos 3.008 indivíduos pertencentes a 90 espécies. Nove eram migradoras, as quais somaram relevante biomassa nas assembleias locais (20 a 60%). Houve variação espacial na estrutura das assembleias, mas fraco efeito sazonal. No geral, a biomassa foi semelhante entre os locais, mas a riqueza tendeu a aumentar em direção a jusante. Peixes migradores apresentaram padrão inverso, com maior riqueza e biomassa a montante, especialmente bagres (Siluriformes). Análises de ordenação separaram os locais em três grupos de acordo com a variação na composição e na abundância, e revelaram correlação entre esses grupos e condições hidro-geomorfológicas específicas (i.e., velocidade, profundidade, largura do canal e vegetação riparia). Nosso estudo revelou que a diversidade de peixes se distribui de maneira heterogênea ao longo do canal, onde características hidro-geomorfológicas selecionam assembleias distintas ao longo de gradientes fluviais.(AU)

Seasonal and longitudinal variation in fish assemblage structure along an unregulated stretch of the Middle Uruguay River

Diversity patterns and their causes remain important questions, especially for ecosystems that preserve natural conditions. This is the case of fish diversity in large Neotropical rivers. In this context, we investigated fish diversity patterns along an extensive unregulated river section (ca. 450 km) in the Middle Uruguay River Basin. Sampling was conducted seasonally between May 2017 and March 2018, at six sites (patches) with contrasting environmental conditions. We collected 3,008 individuals belonging to 90 species. Nine were migratory, which summed relevant biomass in local assemblages (20 to 60%). We observed spatial variation in assemblage structure, but weak seasonal effects. Overall, biomass was similar among sites, but richness tended to increase downstream. Migratory fishes showed opposed trends, with higher richness and biomass upstream, particularly catfishes (Siluriformes). Ordination analyses separated sites in three groups based on variations in composition and abundance, and revealed associations between these groups and specific hydro-geomorphic conditions (i.e., flow, depth, channel width and the presence of riparian vegetation). Our study revealed that fish diversity distributes heterogeneously along the main channel, where hydro-geomorphic patches select for distinct assemblages along riverine gradients.(AU)

Os padrões de diversidade e suas causas continuam sendo questões importantes, especialmente em ecossistemas que preservam condições naturais. Este é o caso da diversidade de peixes em grandes rios neotropicais. Neste contexto, investigamos padrões de diversidade de peixes ao longo de um extenso gradiente fluvial (ca. 450 km) no médio rio Uruguai. As amostragens ocorreram sazonalmente entre maio/2017 e março/2018 em seis locais com condições ambientais distintas. Coletamos 3.008 indivíduos pertencentes a 90 espécies. Nove eram migradoras, as quais somaram relevante biomassa nas assembleias locais (20 a 60%). Houve variação espacial na estrutura das assembleias, mas fraco efeito sazonal. No geral, a biomassa foi semelhante entre os locais, mas a riqueza tendeu a aumentar em direção a jusante. Peixes migradores apresentaram padrão inverso, com maior riqueza e biomassa a montante, especialmente bagres (Siluriformes). Análises de ordenação separaram os locais em três grupos de acordo com a variação na composição e na abundância, e revelaram correlação entre esses grupos e condições hidro-geomorfológicas específicas (i.e., velocidade, profundidade, largura do canal e vegetação riparia). Nosso estudo revelou que a diversidade de peixes se distribui de maneira heterogênea ao longo do canal, onde características hidro-geomorfológicas selecionam assembleias distintas ao longo de gradientes fluviais.(AU)

Variation in the structure of the ichthyoplankton community in the lower Paraíba do Sul River

The Paraíba do Sul River is affected by extensive water collection for supply, organic and industrial pollution, and dams. Nonetheless, the ichthyofauna maintains biodiversity and sustains artisanal fisheries. This study analyzes the composition, abundance and distribution of fish larvae, an important approach to determine the reproductive period and spawning sites. The sampling occurred from August 2011 through February 2013 in five sites at a transect between the banks on the lower reach of the Paraíba do Sul River. A total of 5,412 larvae belonging to 20 taxa was captured. The predominant order was Characiformes. Larvae of Prochilodus spp. and Leporinus spp. were the most abundant; larvae of Brycon insignis, an endangered species, were present. Fewer larvae were collected in the second reproductive cycle during a severe drought. The absence of eggs indicates that the study area is not used for spawning, and highlights the need for studies in the main channel and in the tributaries of the Paraíba do Sul River. Fish larvae need to have access to the marginal lagoons along the lower stretch of the river, an area which is the object of disputes between fishermen and farmers.(AU)

O rio Paraíba do Sul é afetado por retirada de água para abastecimento, poluição orgânica e industrial e barramentos, mas mantém a biodiversidade de peixes e sustenta a pesca artesanal. Este estudo apresenta a composição, abundância e distribuição de larvas de peixes, abordagem importante para determinar o período de reprodução e locais de desova. A amostragem ocorreu entre agosto de 2011 e fevereiro de 2013 em cinco pontos de um transecto de 500 m entre as margens no trecho inferior do rio Paraíba do Sul. Um total de 5.412 larvas de 20 táxons foi capturado. Predominaram Characiformes, sendo que larvas de Prochilodus spp. e Leporinus spp. foram as mais abundantes. Larvas de Brycon insignis, espécie em extinção, foram registradas. Larvas foram menos abundantes no segundo ciclo reprodutivo, coincidindo com o início de uma seca severa na região. A ausência de ovos nas amostras indica que a área estudada não é utilizada para desova e aponta a necessidade de estudos no canal principal a montante e nos afluentes. Ressaltamos a necessidade de acesso das larvas às lagoas marginais no trecho inferior do rio Paraíba do Sul, área objeto de desentendimentos entre pescadores e agricultores.(AU)

Variation in the structure of the ichthyoplankton community in the lower Paraíba do Sul River

The Paraíba do Sul River is affected by extensive water collection for supply, organic and industrial pollution, and dams. Nonetheless, the ichthyofauna maintains biodiversity and sustains artisanal fisheries. This study analyzes the composition, abundance and distribution of fish larvae, an important approach to determine the reproductive period and spawning sites. The sampling occurred from August 2011 through February 2013 in five sites at a transect between the banks on the lower reach of the Paraíba do Sul River. A total of 5,412 larvae belonging to 20 taxa was captured. The predominant order was Characiformes. Larvae of Prochilodus spp. and Leporinus spp. were the most abundant; larvae of Brycon insignis, an endangered species, were present. Fewer larvae were collected in the second reproductive cycle during a severe drought. The absence of eggs indicates that the study area is not used for spawning, and highlights the need for studies in the main channel and in the tributaries of the Paraíba do Sul River. Fish larvae need to have access to the marginal lagoons along the lower stretch of the river, an area which is the object of disputes between fishermen and farmers.(AU)

O rio Paraíba do Sul é afetado por retirada de água para abastecimento, poluição orgânica e industrial e barramentos, mas mantém a biodiversidade de peixes e sustenta a pesca artesanal. Este estudo apresenta a composição, abundância e distribuição de larvas de peixes, abordagem importante para determinar o período de reprodução e locais de desova. A amostragem ocorreu entre agosto de 2011 e fevereiro de 2013 em cinco pontos de um transecto de 500 m entre as margens no trecho inferior do rio Paraíba do Sul. Um total de 5.412 larvas de 20 táxons foi capturado. Predominaram Characiformes, sendo que larvas de Prochilodus spp. e Leporinus spp. foram as mais abundantes. Larvas de Brycon insignis, espécie em extinção, foram registradas. Larvas foram menos abundantes no segundo ciclo reprodutivo, coincidindo com o início de uma seca severa na região. A ausência de ovos nas amostras indica que a área estudada não é utilizada para desova e aponta a necessidade de estudos no canal principal a montante e nos afluentes. Ressaltamos a necessidade de acesso das larvas às lagoas marginais no trecho inferior do rio Paraíba do Sul, área objeto de desentendimentos entre pescadores e agricultores.(AU)

Relationship of Neotropical otter vestiges with environmental and anthropogenic factors / Relação entre os vestígios de lontra neotropical e fatores ambientais e antropogênicos

The Neotropical otter, Lontra longicaudis (Mustelidae) is a semi-aquatic mustelid that exploits a variety of freshwater habitats. To understand the relative influence of human activities and environmental factors affecting its distribution and habitat use, we conducted systematic, seasonal surveys of otter signs along the middle Guamá River, in Pará state in the eastern Brazilian Amazon. We applied generalized additive models to compare distribution of otters along the river with data collected on environmental factors (landcover type derived from satellite imagery, and in situ measurements of physicochemical water characteristics) and anthropogenic factors (fishing gear in the river and human habitation along the river). Most otter signs (indicators of otter habitat use) occurred along the shoreline of the main river channel during the dry season; we observed fewer signs during peak flow, probably because the shoreline and floodplain are flooded, which hid signs and made access to the floodplain difficult. The best-fit model included variables for proportion of forest, presence of fishing gear and boats, bank steepness, and presence of rock formations and sand banks. Otter occurrence was negatively related to forested area and positively related to the presence of fishing gear and boats. Otters are likely attracted to fish trapped in fishing gear because they can easily predate on the trapped fish.(AU)

A lontra neotropical, Lontra longicaudis é um mustelídeo semiaquático que usa seu habitat de diferentes formas. Para entender a influência relativa de fatores antrópicos e ambientais sobre a distribuição de lontras neotropicais, nós conduzimos monitoramentos sistemáticos de vestígios de lontras na região do médio Rio Guamá, Pará, Amazônia Oriental. Modelos aditivos generalizados foram usados para analisar a associação entre a ocorrência de lontras ao longo do rio e variáveis ambientais (cobertura da terra derivada de imagens de satélite e características fisicoquímicas da água medidas in situ) e fatores antrópicos (presença de apetrechos de pesca e comunidades humanas ao longo do rio). A maioria dos vestígios de lontras foi encontrada ao logo das margens do rio durante a estação seca. Obtivemos um número muito menor de registros durante a cheia do rio, provavelmente devida à inundação da linha costeira e da planície de inundação, o que obliterou os sinais e dificultou o acesso à área alagada. O modelo de melhor ajuste incluiu como variáveis explicativas a área florestada, a presença de apetrechos de pesca e barcos, a inclinação das margens e a presença de formações rochosas. A ocorrência de registros de lontra foi relacionada negativamante com a proporção de áreas florestadas, e positivamente com a presença de apetrechos de pesca e barcos. As lontras provavelmente são atraídas por peixes presos em artefatos de pesca, pois podem facilmente predar os peixes presos.(AU)

No mullet, no gain: cooperation between dolphins and cast net fishermen in southern Brazil

We report on the interaction between common bottlenose dolphins, Tursiops truncatus (Montagu, 1821) and cast net fishermen in southern coast of Brazil. The fishery was monitored in the mouth of the Tramandaí River Estuary to investigate the seasonality of catches and their relationships with a set of variables: presence/absence and number of bottlenose dolphins, fishing area, temperature, salinity, wind and water flow direction in the channel. The mullet, Mugil liza Valenciennes, 1836 is the target species and was the dominant fish in the catches (77% of total catch; 50% in frequency; 0.2 ind. x f-1). The use of GLM models helped to reveal that the number of the bottlenose dolphins, time of year (months) and spatial variation of fishing activity were the main factors explaining the presence and abundance of mullet in the fishermen’s catches. The presences of bottlenose dolphins in the fishing area raise the probability of fishermen catch larger number of mullets with smaller fishing effort. However, the size of the mullet is influenced basically by seasonality. The mullets are the “currency” of bottlenose dolphins and fishermen interaction. There are reasons for concern about the sustainability of the southern Brazilian M. liza stock, once the decrease of this fishing resource can lead this rare and traditional fishery to the extinction.

No mullet, no gain: cooperation between dolphins and cast net fishermen in southern Brazil

We report on the interaction between common bottlenose dolphins, Tursiops truncatus (Montagu, 1821) and cast net fishermen in southern coast of Brazil. The fishery was monitored in the mouth of the Tramandaí River Estuary to investigate the seasonality of catches and their relationships with a set of variables: presence/absence and number of bottlenose dolphins, fishing area, temperature, salinity, wind and water flow direction in the channel. The mullet, Mugil liza Valenciennes, 1836 is the target species and was the dominant fish in the catches (77% of total catch; 50% in frequency; 0.2 ind. x f-1). The use of GLM models helped to reveal that the number of the bottlenose dolphins, time of year (months) and spatial variation of fishing activity were the main factors explaining the presence and abundance of mullet in the fishermens catches. The presences of bottlenose dolphins in the fishing area raise the probability of fishermen catch larger number of mullets with smaller fishing effort. However, the size of the mullet is influenced basically by seasonality. The mullets are the “currency” of bottlenose dolphins and fishermen interaction. There are reasons for concern about the sustainability of the southern Brazilian M. liza stock, once the decrease of this fishing resource can lead this rare and traditional fishery to the extinction.(AU)

The contribution of environmental factors to fish assemblages in the Río Acahuapa, a small drainage in Central America

The ichthyofauna of the Río Acahuapa was analyzed sampling 17 sites that included the basin main channel and its tributaries. Fish were collected using dip-nets, seine-nets and electrofishing. Fish standard length and species abundance were recorded. Species origin and salinity tolerance criteria were used to classify fish species. Water physicochemical variables, habitat structure and sampling sites elevation were recorded. A total of 33 fish species were registered, 12.1% are primary, 45.5% are secondary and 42.4% are of marine derivation. Fish species richness declined with increase of elevation (R2=0.55, p=0.0006). Two assemblages of fishes were identified: the first one associated to sites of low elevations (19-184 masl), composed mainly of secondary and marine-estuarine fish species related with high temperature, water velocity, river width, dissolved oxygen and low sand and silt substrate cover; the second one associated to sites of middle and higher elevations (185-519 masl), composed by primary and secondary freshwater fishes related with high pH, logs and rocks substrate cover. In summary, elevation and environmental variables contributed to the composition and distribution of fish in the Río Acahuapa.(AU)

La ictiofauna del Río Acahuapa fue analizada en 17 sitios que incluyen el canal principal de la cuenca y sus tributarios. Los peces fueron recolectados utilizando chinchorros, redes de mano y electropesca. Se registró la longitud estándar y la abundancia por especie. El criterio de origen y tolerancia a la salinidad de las especies fue utilizado para clasificar a los peces. Las variables fisicoquímicas del agua, estructura del hábitat y elevación se registraron en cada sitio. Un total de 33 especies fueron registradas, cuyo 12.1% son primarias, 45.5% secundarias y 42.4% son de derivación marina. La riqueza de especies de peces disminuyó con el aumento de la elevación (R2=0.55, p=0.0006). Dos ensamblajes de peces fueron identificados: el primero está asociado con sitios de bajas elevaciones (19-184 msnm), compuesto principalmente de especies de peces secundarias y marino-estuarinas relacionadas con altas temperaturas, velocidad del agua, ancho de río, oxígeno disuelto y baja cobertura de sustrato de arena y limo; el segundo está asociado con sitios de mediana y alta elevación (185-519 msnm), compuesto por peces dulceacuícolas primarios y secundarios relacionados con altos valores de pH y cobertura de sustrato de troncos y rocas. Se determina que la elevación y las variables ambientales contribuyen a la composición y distribución de peces en el Río Acahuapa.(AU)

The contribution of environmental factors to fish assemblages in the Río Acahuapa, a small drainage in Central America

The ichthyofauna of the Río Acahuapa was analyzed sampling 17 sites that included the basin main channel and its tributaries. Fish were collected using dip-nets, seine-nets and electrofishing. Fish standard length and species abundance were recorded. Species origin and salinity tolerance criteria were used to classify fish species. Water physicochemical variables, habitat structure and sampling sites elevation were recorded. A total of 33 fish species were registered, 12.1% are primary, 45.5% are secondary and 42.4% are of marine derivation. Fish species richness declined with increase of elevation (R2=0.55, p=0.0006). Two assemblages of fishes were identified: the first one associated to sites of low elevations (19-184 masl), composed mainly of secondary and marine-estuarine fish species related with high temperature, water velocity, river width, dissolved oxygen and low sand and silt substrate cover; the second one associated to sites of middle and higher elevations (185-519 masl), composed by primary and secondary freshwater fishes related with high pH, logs and rocks substrate cover. In summary, elevation and environmental variables contributed to the composition and distribution of fish in the Río Acahuapa.(AU)

La ictiofauna del Río Acahuapa fue analizada en 17 sitios que incluyen el canal principal de la cuenca y sus tributarios. Los peces fueron recolectados utilizando chinchorros, redes de mano y electropesca. Se registró la longitud estándar y la abundancia por especie. El criterio de origen y tolerancia a la salinidad de las especies fue utilizado para clasificar a los peces. Las variables fisicoquímicas del agua, estructura del hábitat y elevación se registraron en cada sitio. Un total de 33 especies fueron registradas, cuyo 12.1% son primarias, 45.5% secundarias y 42.4% son de derivación marina. La riqueza de especies de peces disminuyó con el aumento de la elevación (R2=0.55, p=0.0006). Dos ensamblajes de peces fueron identificados: el primero está asociado con sitios de bajas elevaciones (19-184 msnm), compuesto principalmente de especies de peces secundarias y marino-estuarinas relacionadas con altas temperaturas, velocidad del agua, ancho de río, oxígeno disuelto y baja cobertura de sustrato de arena y limo; el segundo está asociado con sitios de mediana y alta elevación (185-519 msnm), compuesto por peces dulceacuícolas primarios y secundarios relacionados con altos valores de pH y cobertura de sustrato de troncos y rocas. Se determina que la elevación y las variables ambientales contribuyen a la composición y distribución de peces en el Río Acahuapa.(AU)

Impact of damming on the Chironomidae of the upper zone of a tropical run-of-the-river reservoir

Abstract We examined the effects of the Mogi-Guaçu river damming (São Paulo State, Brazil) on the Chironomidae fauna. Pre, during, and post-filling sampling was carried out in the main channel and margins of one site in the upper zone of the reservoir, using a modified Petersen grab (325 cm2). We evaluated the total, subfamily, and tribe densities and also their relative abundance. Analysis of genera included densities, relative abundance, richness, and dominance. The Rossos ecological value index (EVI) determined the ecological importance of each genus. There was a tendency of decrease of the total Chironomidae density, increase in the percentage of Chironomini, and decrease in densities and percentages of Orthocladiinae and Tanytarsini. These changes in percentage were respectively related to Polypedilum, Lopescladius, and Rheotanytarsus, the genera with the highest EVI values. After-filling richness was lower in the margins and dominance of genera did not change significantly. Chironomidae in the margins was more sensitive to damming than in the main channel. This difference in sensibility sustains the use of Chironomidae as bioindicators. Damming impact was indicated by the reduction of both genera richness in the margins and relative abundance of groups typical of faster waters. The results have highlighted the need for multi-habitat analysis combined with a before-after sampling approach in the environmental impact studies concerning the damming impact on the benthic fauna.

Resumo Este trabalho teve como objetivo avaliar o impacto do represamento do Rio Mogi-Guaçu, em um ponto situado na zona de remanso do reservatório, através da utilização da taxocenose Chironomidae. A amostragem foi realizada antes, durante e após o represamento, no canal e nas margens, com o auxílio de um pegador Petersen modificado (área de 325 cm2). Calculou-se a densidade total, de subfamílias, tribos e gêneros de Chironomidae, bem como sua abundância relativa. Estimou-se a riqueza e a dominância de gêneros. O índice de valor ecológico de Rosso (IVE) foi utilizado para avaliar a importância ecológica dos diferentes gêneros. Houve tendência de redução da densidade total de Chironomidae, aumento da abundância relativa de Chironomini e diminuição das abundâncias relativas de Orthocladiinae e Tanytarsini. Estas alterações de abundância relativa foram relacionadas respectivamente a Polypedilum, Lopescladius e Rheotanytarsus, gêneros que apresentaram os maiores valores de IVE. Após o represamento, houve decréscimo da riqueza de gêneros na margem, enquanto a dominância não apresentou alteração significativa. A taxocenose de Chironomidae das margens mostrou-se mais sensível ao represamento que a do canal. Esta diferença de sensibilidade confirma o potencial dos Chironomidae como bioindicadores. A ocorrência de impacto foi observada através da diminuição da riqueza de gêneros nas margens e da abundância relativa de táxons característicos de águas mais rápidas. Os resultados chamam atenção para a necessidade de utilizar a abordagem de múltiplos habitats combinada com a amostragem antes e depois do evento na avaliação dos impactos causados por represamento sobre a fauna bentônica.

Impact of damming on the Chironomidae of the upper zone of a tropical run-of-the-river reservoir / Impacto de um represamento sobre Chironomidae do remanso de um reservatório fio dágua tropical

Abstract We examined the effects of the Mogi-Guaçu river damming (São Paulo State, Brazil) on the Chironomidae fauna. Pre, during, and post-filling sampling was carried out in the main channel and margins of one site in the upper zone of the reservoir, using a modified Petersen grab (325 cm2). We evaluated the total, subfamily, and tribe densities and also their relative abundance. Analysis of genera included densities, relative abundance, richness, and dominance. The Rossos ecological value index (EVI) determined the ecological importance of each genus. There was a tendency of decrease of the total Chironomidae density, increase in the percentage of Chironomini, and decrease in densities and percentages of Orthocladiinae and Tanytarsini. These changes in percentage were respectively related to Polypedilum, Lopescladius, and Rheotanytarsus, the genera with the highest EVI values. After-filling richness was lower in the margins and dominance of genera did not change significantly. Chironomidae in the margins was more sensitive to damming than in the main channel. This difference in sensibility sustains the use of Chironomidae as bioindicators. Damming impact was indicated by the reduction of both genera richness in the margins and relative abundance of groups typical of faster waters. The results have highlighted the need for multi-habitat analysis combined with a before-after sampling approach in the environmental impact studies concerning the damming impact on the benthic fauna.(AU)

Resumo Este trabalho teve como objetivo avaliar o impacto do represamento do Rio Mogi-Guaçu, em um ponto situado na zona de remanso do reservatório, através da utilização da taxocenose Chironomidae. A amostragem foi realizada antes, durante e após o represamento, no canal e nas margens, com o auxílio de um pegador Petersen modificado (área de 325 cm2). Calculou-se a densidade total, de subfamílias, tribos e gêneros de Chironomidae, bem como sua abundância relativa. Estimou-se a riqueza e a dominância de gêneros. O índice de valor ecológico de Rosso (IVE) foi utilizado para avaliar a importância ecológica dos diferentes gêneros. Houve tendência de redução da densidade total de Chironomidae, aumento da abundância relativa de Chironomini e diminuição das abundâncias relativas de Orthocladiinae e Tanytarsini. Estas alterações de abundância relativa foram relacionadas respectivamente a Polypedilum, Lopescladius e Rheotanytarsus, gêneros que apresentaram os maiores valores de IVE. Após o represamento, houve decréscimo da riqueza de gêneros na margem, enquanto a dominância não apresentou alteração significativa. A taxocenose de Chironomidae das margens mostrou-se mais sensível ao represamento que a do canal. Esta diferença de sensibilidade confirma o potencial dos Chironomidae como bioindicadores. A ocorrência de impacto foi observada através da diminuição da riqueza de gêneros nas margens e da abundância relativa de táxons característicos de águas mais rápidas. Os resultados chamam atenção para a necessidade de utilizar a abordagem de múltiplos habitats combinada com a amostragem antes e depois do evento na avaliação dos impactos causados por represamento sobre a fauna bentônica.(AU)

Microbiota fúngica e de enterobactérias em tartarugas da Amazônia (Podocnemis expansa Schweigger, 1812) criadas em cativeiros comerciais em Iranduba - Amazonas

A tartaruga da Amazonia (Podocnemis expansa) e a maior especie de seu genero, chegando a medir 90 cm de comprimento e pesando ate 65 kg. Ocorre em quase todos os afluentes do Rio Amazonas, desde o Leste dos Andes ate a Bacia do Rio Orinoco, seu estado de conservacao no territorio brasileiro e de quase ameacada de extincao, e para a regiao Amazonica, categoriza-se como criticamente ameacada. E uma especie considerada de alto valor comercial e uma iguaria na culinaria amazonica. Tartarugas aquaticas sao naturalmente hospedeiros de bacterias (dentre elas Salmonella spp.) e acometidos por fungos devido ao ambiente umido que habitam. Neste sentido, o objetivo deste trabalho foi identificar a diversidade fungica e bacteriana associada a cloaca de quelonios em criadouros comerciais em Iranduba, Amazonas, analisando a relacao entre a presenca destes micro-organismos e o sexo do animal, a fase de criacao e o tipo de instalacao. O esfregaco cloacal foi realizado com auxilio de swab esteril, comercializado com o meio para transporte Stwart, acondicionado em tubo com tampa de rosca. Apos as coletas, as amostras foram transportadas em caixas isotermicas ao Laboratorio de Principios Bioativos de Origem Microbiana da Faculdade de Ciencias Agrarias da UFAM onde foram feitas as analises. Visando a pesquisa de enterobacterias, os swabs foram inoculados inicialmente em caldo BHI, e incubados a 37 oC/24h, apos este periodo foi feito esfregaco em Agar MacConkey, com incubacao em aerobiose a 37 oC com leitura em 24-48h. A identificacao foi feita por meio de testes bioquimicos nos agares Triple Sugar Iron Agar (TSI), Lisine Iron Agar (LIA) e Agar Sulfeto Indol Motilidade (SIM), onde, uma amostra das colonias isoladas foram incubadas a 36°C por 24 horas, a fim de verificar a suar reacoes em cada um destes meios. Para o isolamento de fungos, 1ml do conteudo do caldo BHI foi inoculado em caldo Sabouraud acrescido de Cloranfenicol e incubado a 25°C por 72 horas. Apos esse periodo o conteudo deste caldo foi estriado em agar Sabouraud com Cloranfenicol e incubado a 25°C por mais 72 horas, as unidades formadoras de colonias foram isoladas novamente em Agar Sabouraud e preservadas pelo metodo Catellani, sendo este submetido a avaliacoes diarias. Os fungos filamentosos foram identificados microscopicamente, com base em suas caracteristicas morfologicas. Ao todo, foram realizadas coletas cloacais e biometrias de 102 animais, sendo de 96 de tartarugas (P.expansa), 3 de tracaja (P.unifilis) e 3 de iacas (P.sextuberculata) criados em diferentes instalacoes. No presente trabalho nao houve diferenca significativa tanto no peso dos reprodutores de P.expansa criados em tanque escavado e em canal de igarape, quanto no tamanho e peso entre machos e femeas nos tanques escavados com lotes comerciais. Foram 16 especies de bacterias identificadas e 4 generos de fungos.

The Amazonian turtle (Podocnemis expansa) is the largest species of its genus, reaching 90 cm in length and weighing up to 65 Kg. It occurs in almost all tributaries of the Amazon River, from the Eastern Andes to the Orinoco River Basin, its state of conservation in the Brazilian territory is almost threatened with extinction, and for the Amazon region as a whole, it is categorized as critically threatened. It is a species considered of high commercial value and a delicacy in the Amazonian cuisine. Aquatic turtles are naturally hosts of bacteria (among them Salmonella spp.) And are affected by fungi due to the humid environment they inhabit. In this sense, a study of the bacterial and fungal species present will be done in five commercial breeders, duly authorized by IBAMA, following the normative instructions that govern such analyzes. The objective was to recognize the bacterial species and identify the main morphological groups of fungi present in chelonians. For bacterial analyzes, cloacal samples of 100 animals will be collected. The cloacal swab will be performed with the aid of a sterile swab, placed in a glass tube with a screw cap, containing 10 mL of 1% peptone water. After collection, the samples will be transported in isothermal boxes to the Laboratorio de Principios Bioativos de Origem Microbiana of the Faculdade de Ciencias Agrarias of UFAM where the analyzes will be initiated with incubation at 37 °C/24h. In order to investigate aerobic and facultative anaerobic bacteria, the swabs will be initially inoculated in 1% peptone water and incubated at 37oC / 24h. The samples will be parallelly seeded in MacConkey Agar, with aerobic incubation at 37oC with reading in 24-48h. Isolation of Salmonella spp. Will be done, following the methodology standardized by IN 62 of 2003 of the Ministry of Agriculture, Livestock and Supply (MAPA). The data of the microbiological analysis will be structured in non-parametric format, in a descriptive way, with calculations of frequency percentages relative to the detection of Salmonella spp. For fungal isolation, the samples will be cultured in Sabouraud Dextrose Agar and Malt Extract Agar (MEA), with chloramphenicol (100 mg / L) to inhibit bacterial growth, with incubation at 25 ° C for a period of three days to the Sabouraud Dextrose Agar and seven days for the MEA, which was submitted to daily evaluations. Filamentous fungi will be identified microscopically, based on their morphological characteristics. Altogether, cloacal collections and biometrics of 102 animals were carried out, 96 of Giant South american river turtle (P.expansa), 3 of Yellow-spotted river turtle (P.unifilis) and 3 of Six-tubercled river turtle (P.sextuberculata) raised in different facilities. In the present study, there was no significant difference both in the weight of the P.expansa breeders raised in an excavated tank and in an igarape channel, as well as in the size and weight between males and females in the tanks excavated with commercial lots. There were 16 species of bacteria identified and 4 genera of fungi.