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Caffeine is a contaminant frequently detected in water bodies. Growth trends in both human population and caffeine consumption per capita are expected to exacerbate the occurrence of caffeine in freshwaters. Yet the effects of caffeine on native fish fauna are poorly understood. We exposed larvae of an endemic Neotropical catfish (Rhamdia quelen) to a range of caffeine concentrations for 30 days. We found that larvae exposed to the highest concentration (16 mg L

Neotropical Ichthyology promotes the Special Issue (SI) “Human impacts and the loss of Neotropical freshwater fish diversity” with the purpose of publishing relevant scientific articles on the current biodiversity crisis and the loss of Neotropical freshwater fishes in the Anthropocene. The SI is composed of 22 publications, being two review articles and 20 original articles. A total of 107 researchers contributed to these papers, involving 44 institutions based in Brazil and six other countries. Published articles investigated main anthropic activities and their impacts on fish diversity, with special focus on river regulation, mining, land use changes, aquaculture, and fisheries. Studies provided evidence about the loss of fish diversity in the Neotropics, including fish kill events, demographic changes, contamination, changes in assemblage structure, loss of taxonomic and functional diversity, besides the degradation of ecosystem functions and services, and the lack of effective protection and conservation. Studies were conducted in rivers, streams, lakes, and reservoirs from different Neotropical systems. The studies published in this SI represent a relevant sample of the current worrisome situation of freshwater fishes in the Neotropical region and call for urgent revision in environmental policies, management and conservation initiatives, and socioeconomic priorities. Resumo A revista Neotropical Ichthyology lança o Volume Especial (SI) “Human impacts and the loss of Neotropical freshwater fish diversity” com o objetivo de publicar artigos científicos relevantes sobre a atual crise da biodiversidade e a perda de diversidade de peixes de água doce Neotropicais no Antropoceno. O SI é composto por 22 publicações, sendo dois artigos de revisão e 20 artigos originais. Um total de 107 pesquisadores contribuíram com esses artigos, envolvendo 44 instituições sediadas no Brasil e em seis outros países. Os artigos publicados investigaram as principais atividades antrópicas e seus impactos sobre a diversidade de peixes, com foco especial na regulação dos rios, mineração, mudanças no uso do solo, aquicultura e pesca. Os estudos forneceram evidências sobre a perda de diversidade de peixes na região Neotropical, incluindo eventos de mortandade, alterações demográficas, contaminação, mudanças na estrutura das assembleias, perda de diversidade taxonômica e funcional, além da degradação de funções e serviços ecossistêmicos, e falta de ações efetivas de proteção e conservação. Os estudos foram conduzidos em rios, riachos, lagos e reservatórios de diferentes sistemas Neotropicais. Os estudos publicados neste SI representam uma amostra relevante da atual situação dos peixes de água doce na região Neotropical, reforçando a necessidade de revisão das políticas ambientais, ações de manejo e conservação, e prioridades socioeconômicas.

Diet and morphology of Serrapinnus notomelas and Serrapinnus sp.1 were investigated across ontogeny, as a way to elucidate the key elements linked to the resource partitioning (a main driver for species coexistence). Fish sampling was conducted monthly between October 2010 and March 2012. Individuals were captured, identified, and classified into juvenile or adult. Our results show ontogenetic and interspecific differences in feeding abilities and morphological traits. Differences in body shape (relative area of the dorsal fin, length of head, height of the caudal peduncle, the aspect ratio of the pectoral and pelvic fin) favored divergent swimming performances (more maneuverability in S. notomelas and continuous swimming to Serrapinnus sp.1). We also observed divergences in trophic apparatus traits and correlations with different diets. In this context, it is highlighted that understanding the relationship between morphology and diet can assist in elucidating the processes that permeate the coexistence between sympatric species, and between ontogenetic periods. Besides, the relevant contribution of the measures of the trophic apparatus (gill raker length, the number of teeth cuspids, and intestinal coefficient) in trophic segregation seems to be a strong evidence in favor of the proposed discriminatory and predictive capacities of these traits. Resumo Dieta e morfologia de Serrapinnus notomelas e Serrapinnus sp.1 foram investigadas ao longo da ontogenia, como forma de elucidar os principais elementos ligados à partição de recursos (principal fator para a coexistência entre espécies). Foram realizadas coletas de peixes mensalmente entre outubro de 2010 e março de 2012. Os indivíduos foram capturados, identificados e classificados em juvenis ou adultos. Nossos resultados mostram diferenças ontogenéticas e interespecíficas na alimentação e características morfológicas. Diferenças na forma corporal (área da nadadeira dorsal, comprimento da cabeça, altura do pedúnculo caudal, proporção das nadadeiras peitorais e pélvicas) favoreceram desempenhos de natação divergentes (maior manobrabilidade para S. notomelas e natação contínua para Serrapinnus sp.1). Também observamos divergências nas características do aparato trófico e correlações com diferentes dietas. Nesse contexto, destaca-se que compreender a relação entre morfologia e dieta pode auxiliar na elucidação dos processos que permeiam a coexistência entre espécies simpátricas e entre períodos ontogenéticos. Além disso, a relevante contribuição das medidas do aparato trófico (número de cúspide nos dentes, rastros branquiais e coeficiente intestinal) na segregação trófica parece ser uma forte evidência a favor das propostas de capacidades discriminatórias e preditivas dessas características.

Resumo Objetivo Comparar a percepção de estudantes de enfermagem e as contribuições do ensino com simulação clínica ou aula prática convencional em laboratório de habilidades, na primeira experiência clínica hospitalar. Método Pesquisa descritiva, qualitativa, envolvendo estudantes de graduação em enfermagem de uma universidade pública do Brasil, submetidos à simulação clínica de alta fidelidade ou aula prática convencional, ocorrida entre 2015 e 2016. Para avaliação dos dados, utilizaram-se a nuvem de palavras e a análise de similitude do software IRAMUTEQ®. Resultados Participaram 54 estudantes, sendo 27 em cada grupo. As palavras mais evocadas pelo grupo simulação foram: “paciente real, não, mais e simulador”, relacionadas à capacidade de reflexão quanto ao seu conhecimento e preparo. As mais evocadas no grupo prática convencional foram: “mais, não, muito e sentir”, relacionadas com a percepção de que a aula convencional ajuda na aquisição de habilidades, contudo, é necessária maior frequência. Conclusão As duas estratégias contribuíram positivamente para a primeira experiência clínica hospitalar. Porém, a simulação proporcionou uma visão crítico-reflexiva sobre as competências, deficiências e maior autoconfiança em relação à prática convencional. Este estudo fortalece as evidências dos benefícios proporcionados pelo ensino baseado em simulação, e a importância de instituições de ensino fazerem uso adequado dessa estratégia. Resumen Objetivo Comparar la percepción de los estudiantes de enfermería y las contribuciones docentes con simulación clínica o clase práctica convencional en un laboratorio de habilidades, en la primera experiencia clínica hospitalaria. Métodos Investigación descriptiva y cualitativa con estudiantes universitarios de enfermería en una universidad pública de Brasil, sometidos a simulación clínica de alta fidelidad o clase práctica convencional, entre 2015 y 2016. Para el análisis de los datos se utilizo, una nube de palabras y el análisis de la similitud por el software IRAMUTEQ. Resultados Participaron 54 estudiantes, 27 en cada grupo. Las palabras mas evocadas por el grupo de simulación fueron: “paciente real, no, más y simulador” relacionadas con la capacidad de reflexionar sobre su conocimiento y preparación. Los más mencionados en el grupo práctica convencional fueron: “más, no, mucho y sentir”, relacionadas con la percepción de que la clase convencional ayuda en la adquisición de habilidades, sin embargo se necesita más frecuencia. Conclusion Ambas estrategias contribuyeron positivamente para la primera experiencia clínica hospitalaria. Sin embargo, la simulación proporcionó una visión crítica reflexiva de las habilidades, deficiencias y una mayor autoconfianza en comparación con la práctica convencional. Este estudio fortalece la evidencia de los beneficios proporcionados por la enseñanza basada en simulación y la importancia de que las instituciones educativas hagan uso adecuado de esta estrategia. Abstract Objective to compare the perception of nursing students and the contributions of teaching with clinical simulation or conventional practical classroom skills in the first clinical hospital experience. Method a descriptive, qualitative research involving undergraduate nursing students from a public university in Brazil, submitted to a high fidelity clinical simulation or conventional practical class, which took place between 2015 and 2016. For data evaluation, a word cloud and similarity analysis of the IRAMUTEQ® software were used. Results Altogether 54 students participated, 27 of them in each group. The words most evoked by the simulation group were: “real patient, no, more and simulator”, related to the capacity of reflection regarding their knowledge and preparation. The most evoked by the conventional practice group were: “more, no, much and feel”, related with the perception that the conventional class helps in the acquisition of skills, however, more frequency is needed. Conclusion Both strategies contributed positively to the first clinical hospital experience. However, the simulation provided a critical-reflexive view of skills, deficiencies and greater self-confidence in relation to conventional practice. This study strengthens the evidence of the benefits provided by simulation-based teaching, and the importance of teaching institutions making appropriate use of this strategy.

Resumo Objetivo: Traduzir para a língua portuguesa e adaptar transculturalmente para o Brasil o Creighton Competency Evaluation Instrument. Métodos: Pesquisa metodológica que adotou o referencial de Beaton para o processo de tradução e adaptação transcultural, que ocorreu em seis etapas: tradução, síntese das traduções, retrotradução, submissão ao comitê de especialistas, pré-teste e parecer do autor original. Participaram dois tradutores, dois retrotradutores e oito membros no comitê de especialistas. O pré-teste foi realizado com 32 participantes. Resultados: Após ajustes linguísticos, a versão final obteve concordância de 100% pelo Índice de Validade de Conteúdo. A confiabilidade (Alfa de Cronbach) foi de 0,897, considerado um ótimo resultado. O instrumento foi classificado como de fácil utilização por 84,4% dos experts. Conclusão: A tradução e a adaptação transcultural disponibiliza para a comunidade acadêmica brasileira um instrumento objetivo e prático, com possibilidade de feedback imediato aos estudantes nas avaliações durante a atividade clínica simulada. Resumen Objetivo: Traducir al idioma portugués y adaptar transculturalmente para Brasil el Creighton Competency Evaluation Instrument. Métodos: Investigación metodológica que adoptó el marco referencial de Beaton para el proceso de traducción y adaptación transcultural, realizada en seis etapas: traducción, síntesis de las traducciones, retrotraducción, presentación al comité de especialistas, prueba piloto y opinión del autor original. Participaron dos traductores, dos retrotraductores y ocho miembros del comité de especialistas. La prueba piloto fue realizada con 32 participantes. Resultados: Después de los ajustes lingüísticos, la versión final obtuvo una concordancia del 100 % mediante el Índice de Validez de Contenido. La fiabilidad (Alfa de Cronbach) fue de 0,897, considerado un excelente resultado. El instrumento fue clasificado como fácil de utilizar por el 84,4 % de los especialistas. Conclusión: La traducción y la adaptación transcultural pone a disposición de la comunidad académica brasileña un instrumento objetivo y práctico, con posibilidad de feedback inmediato a los estudiantes en las evaluaciones durante la actividad clínica simulada. Abstract Objective: To translate and adapt the Creighton Competency Evaluation Instrument for Brazil. Methods: A methodological research that adopted Beaton's framework for the process of translation and cross-cultural adaptation, which took place in six stages: translation, synthesis of translations, back-translation, submission to the expert committee, pre-test and opinion of the original author. Two translators, two back-translators and eight members of the expert committee participated. Pre-test was carried out with 32 participants. Results: After linguistic adjustments, the final version obtained 100% agreement by the Content Validity Index. Reliability (Cronbach's alpha) was 0.897, which is considered an excellent result. The instrument was classified as easy to use by 84.4% of experts. Conclusion: Translation and cross-cultural adaptation provide the Brazilian academic community with an objective and practical tool, with the possibility of immediate feedback to students in assessments during simulated clinical activities.

Resumo Objetivo: Validar construto e avaliar a confiabilidade do Instrumento Creighton para Avaliação de Competências Clínicas, versão português, Brasil. Métodos: Estudo metodológico, realizado com 30 docentes/enfermeiros que utilizavam a metodologia de simulação. Foram elaborados dois cenários com temas iguais e atuações divergentes das estudantes com o objetivo de testar a capacidade do instrumento de diferenciá-los. Os cenários foram gravados e disponibilizados para os especialistas por um website que viabilizou a coleta. Para a validação de construto, utilizou-se as técnicas de experimentação e da correlação phi. Para a confiabilidade, analisou-se a equivalência, com coeficiente Fleiss Kappa, e a consistência interna, com coeficiente Kuder-Richardson (KR20). Resultados: Ao analisar a validade, 20 dos 23 itens apresentaram resultados significativos. Na análise, os domínios apresentaram correlações, classificadas de baixa a alta. Quando comparados os cenários, as correlações foram baixas, muito baixas ou negativas. Quanto à confiabilidade, o coeficiente Fleiss Kappa encontrado foi razoável (0,282) para o cenário 1 e moderado para o cenário 2 (0,408). A consistência interna medida com o KR20 foi de 0,717 para o cenário 1 e 0,805 para o cenário 2, classificadas como moderada e alta. Conclusão: O Instrumento Creighton para Avaliação de Competências Clínicas versão português, Brasil, foi considerado válido e confiável para uso em todo o território nacional.

Flow-dependent fish specialists require specific conditions for reproduction, so the success and reproductive intensity of these animals are determined by the flood regime. Thus, this study investigated the spatial and temporal reproductive patterns of fish, especially migratory Prochilodus species (flow-dependent specialists) in an unusual period of low flow in the Para River sub-basin, one of the main tributaries of the upper Sao Francisco River. For this, ichthyoplankton collections were carried out between November 2013 and February 2014. Data were analysed considering the spatial and temporal variations in density of eggs and larvae for the upper, middle, and lower portions of the Para River sub-basin, and correlating this to some environmental variables. The results showed that the small headwater stretch of the Para River is one relevant spawning area for migratory fish species. However, this area is isolated by the Cajuru reservoir, which makes it uncertain the recruitment of these embryos, due to interruption of natural drift between spawning/nursery areas caused for reservoirs. Larvae of newly hatched migratory species found in tributaries of the lower Para River sub-basin also indicate these species use these tributaries as spawning grounds and migratory routes. The period in which the research was conducted represented the most atypical low flow, one in the last 75 years, resulting in the low variability in the environmental parameters. Although few parameters increased briefly in this low flow period influenced by greater rainfall in December, this precipitation was possibly responsible for the final gonadal maturation and spawning of migratory species.

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

The diversity of fish larvae in floodplain environments exhibits spatial and temporal variations since fish have different ontogenetic requirements, and is influenced by their reproductive period. In order to evaluate how the diversity of fish larvae is structured in different temporal and spatial scales in the sub-basin of the Ivinhema River, Upper Parana River floodplain (MS, Brazil), we performed monthly samplings in two reproductive periods (2010/2011 and 2011/2012). Variation in alpha (α) diversity was evaluated through a nested ANOVA, while beta (β) diversity was evaluated with distance-based tests for the homogeneity of multivariate dispersions (PERMDISP). Additive partitioning of diversity was used to verify the relative contribution of each scale to gamma (γ) diversity. The first reproductive period showed higher intensity and duration of flooding, which favored a higher γ diversity. Alpha and beta diversities also varied among the different habitats, each one being occupied by species with distinct reproductive strategies. Components β1 (variation among months) and β3 (variation among habitats) significantly explained γ diversity in both reproductive periods, indicating that more intense floods favor reproduction and increase diversity of fish larvae. This study reinforces the importance of temporal and spatial scales in the maintenance of fish larvae diversity in floodplains.

Fish reproduction in natural environments tends to occur in conditions, including extreme pH values, ideal for the survival of offspring. In this context, the purpose of this study was to assess the influence of pH on both survival and early development of two fish species, Astyanax lacustris (short-distance migrating fish) and Piaractus mesopotamicus (long-distance migrating fish), with different reproductive strategies. Our experiments were divided into two tests (incubation and larviculture) at five pH levels. First was incubation through a water recirculation system using 2 L incubators followed by larviculture using a 2.5 L aquarium. pH had no influence on the hatching rate of A. lacustris eggs, but affected the yolk-sac diameter, while the newly-hatched larvae had some skeletal disorders. For P. mesopotamicus, pH influenced the hatching rate and perivitelline space, while the newly-hatched larvae had several skeletal disorders. The larviculture of A. lacustris revealed no effect on the survival rate, but the analyzed morphometric variables indicated significant differences between the treatments. An acidic pH negatively influenced the survival rate of P. mesopotamicus, and all morphometric variables also varied significantly between the treatments. We concluded that both the survival and development of A. lacustris and P. mesopotamicus revealed different responses at pH levels during incubation and larviculture tests.

SANCHES, Paulo Vanderlei; NAKATANI, Keshiyu; BIALETZKI, Andréa; BAUMGARTNER, Gilmar; GOMES, Luiz Carlos; LUIZ, Elaine Antoniassi. Flow regulation by dams affecting ichthyoplankton: the case of the Porto Primavera Dam, Paraná River, Brazil. River Research and Applications, Chichester, v.22, no.5, p.555-565, 2006. The effects of a dam closure (Porto Primavera Dam) on reproduction of the main species that use the floodplain located below a nursery area were determined. Specifically, we examined, before and after the closure of the dam, the spatial distribution of larvae and the differences in density according to life strategy (migratory and non-migratory species). Fifteen points distributed along the channels of the Paraná, Ivinheima and Paranapanema rivers were sampled, between 1997 and 2001, (October 1997 to December 1998 pre; and between January 1999 to March 2001 post closure), during the spawning period of most fish species found in the region (October to March). Samplings were always conducted at night, using a conical-cylindrical plankton net (0.5mm mesh) with a flowmeter attached. There were significant differences in larvae densities between pre and post dam closure for several species. Also, there were significant differences between the pre and post-closure periods for densities of migratory and non-migratory species, and between sampling sites. These findings indicate decline in densities and number of taxa caught after the closure of the dam. Larvae of migratory species, formerly common in the entire study area, were registered only in points influenced by the non dammed rivers (such as the Ivinheima River), indicating that the closure of Porto Primavera caused negative impacts on fish reproduction downstream of the dam.

BIALETZKI, Andréa; BAUMGARTNER, Gilmar; SANCHES, Paulo Vanderlei; GALUCH, André Vieira; LUVISUTO, Marli Aparecida; NAKATANI, Keshiyu; CAVICCHIOLI-MAKRAKIS, Maristela; BORGES, Marta Eliane Echeverria. Caracterização do desenvolvimento inicial de Auchenipterus osteomystax (Osteichthyes, Auchenipteridae) da bacia do rio Paraná, Brasil. Acta Scientiarum, Maringá, v.23, n.2, p.377-382, 2001. The aim of the present study was to characterize the early development of Auchenipterus osteomystax (Ribeiro, 1918) (Osteichthyes, Auchenipteridae). Specimens were taken from plankton samples in the Upper Paraná river, Ivaí river, Upper Ivinhema river and Itaipu Reservoir. Seventy-four larvae and seven juveniles (with standard length ranging from 5.25 mm to 39.0 mm) were analyzed. Specimens were identified and separated according to their development and morphometric and meristic analyses were performed. The early development of A. osteomystax follows the pattern of other Siluriformes. However, individuals presented more pigmentation on the head and on fore part of the body. Number of myomeres ranged from 44 to 50. O objetivo deste trabalho é caracterizar o desenvolvimento inicial de Auchenipterus osteomystax (Ribeiro, 1918) (Osteichthyes, Auchenipteridae). O material analisado é proveniente de amostras coletadas no plâncton no alto rio Paraná, rio Ivaí, alto rio Ivinhema e reservatório de Itaipu. Foram analisadas 74 larvas e 7 juvenis, entre 5,25 mm e 39 mm de comprimento padrão. Os espécimes foram identificados e separados em diferentes estágios, e foram obtidas as variáveis morfométricas e merísticas. As larvas de A. osteomystax apresentam o desenvolvimento inicial semelhante ao de outros Siluriformes, no entanto são caracterizadas principalmente por apresentar um aglomerado de pigmentos na cabeça e na região anterior do corpo e número de miômeros variando de 44 a 50. Abstract: The aim of the present study was to characterize the early development of Auchenipterus osteomystax (Ribeiro, 1918) (Osteichthyes, Auchenipteridae). Specimens were taken from plankton samples in the Upper Paraná river, Ivaí river, Upper Ivinhema river and Itaipu Reservoir. Seventy-four larvae and seven juveniles (with standard length ranging from 5.25 mm to 39.0 mm) were analyzed. Specimens were identified and separated according to their development and morphometric and meristic analyses were performed. The early development of A. osteomystax follows the pattern of other Siluriformes. However, individuals presented more pigmentation on the head and on fore part of the body. Number of myomeres ranged from 44 to 50.

MAKRAKIS, Maristela Cavicchioli; NAKATANI, Keshiyu; BIALETZKI, Andréa; SANCHES, Paulo Vanderlei; BAUMGARTNER, Gilmar; GOMES, Luiz Carlos. Ontogenetic shifts in digestive tract morphology and diet of fish larvae of the Itaipu Reservoir, Brazil. Environmental Biology of Fishes, Dordrecht, v.72, no.1, p.99-107, 2005. We analyzed the ontogenetic shifts in digestive tract morphology and diets of the young of Iheringichthys labrosus, Hypophthalmus edentatus and Plagioscion squamosissimus, sampled in the Itaipu Reservoir, Brazil-Paraguay.We described the dental structures, the gill rakers and the digestive tract, and analyzed the diet of the young fish. We observed teeth in the jaws and pharynx in young of the three species. In H. edentatus, the gill rakers developed more rapidly, and were longer and more numerous on the first arch, related to their planktivorous feeding habit. I. labrosus and P. squamosissimus had long gill rakers only on the first arch, they were short and thick on the rest. The stomach was defined only in P. squamosissimus, with pyloric caeca. Their diets were mainly zooplankton. I. labrosus fed particularly on cladocerans and rotifers; H. edentatus consumed essentially cladocerans; and P. squamosissimus fed basically on copepods. We observed greater similarity in diet between the young of I. labrosus and H. edentatus, especially for the first length classes. The diet of I. labrosus became more diversified at the end of the larval period, indicating a transition in the feeding habit and habitat for this species. P. squamosissimus showed a very different diet from the others species. The differences in oral anatomy, allied to the morphology of the digestive tract, visual acuity, swimming hability, way of foraging, and especially mouth position, form and size, were determining factors in the diets of these species.

BAUMGARTNER, Gilmar; NAKATANI, Keshiyu; GOMES, Luiz Carlos; BIALETZKI, Andréa; SANCHES, Paulo Vanderlei; MAKRAKIS, Maristela Cavicchioli. Identification of spawning sites and natural nurseries of fishes in the upper Paraná River, Brazil. Environmental Biology of Fishes, Dordrecht, v.71, no.2, p.115-125, 2004. We studied the timing of migratory fish spawning in the last dam-free stretch of the upper Paraná River and in Itaipu Reservoir. Eggs were more common in the Amambai and Ivaí Rivers, while larvae predominated in the Paraná River and in Itaipu Reservoir. Both eggs and larvae were more abundant at night. The highest abundance of eggs was in October and that of larvae in November. Migratory species predominated in the Amambai and Paraná Rivers, and non-migratory species in the Ivaí River and Itaipu Reservoir. The predominance of eggs in the upper and middle portions, and larvae in the lower, infer that there are spawning sites in the former and nurseries in the latter. The high nocturnal abundance of eggs is associated with spawning at sunset and that of larvae with feeding, avoidance of predators and nocturnal disorientation. The presence of tributaries such as the Amambai and Ivaí Rivers in the last dam-free stretch of the Paraná River is extremely important to the maintenance of regional fish diversity and fish stocks in both the Paraná River and Itaipu Reservoir.

BIALETZKI, Andréa; NAKATANI, Keshiyu.; SANCHES, Paulo Vanderlei; BAUMGARTNER, Gilmar; GOMES, Luiz Carlos. Larval fish assemblage in the Baía River (Mato Grosso do Sul State, Brazil): temporal and spatial patterns. Environmental Biology of Fishes, Dordrecht, v.73, no.1, p.37-47, 2005. We sampled the Baía River (Mato Grosso do Sul State, Brazil) monthly, to survey taxonomic composition and temporal and spatial distribution of fish larvae. The ichthyoplankton was mainly composed by larvae of small and medium sized sedentary species and it was numerically dominated by six taxa: Plagioscion squamosissimus, Hypophthalmus edentatus, Hoplias aff. malabaricus, Bryconamericus stramineus, Serrasalmus spp. and Catathyridium jenynsii. These taxa present distinct temporal and spatial occurrence patterns: H. edentatus, B. stramineus and C. jenynsii are abundant between September and March in lentic areas; H. aff. malabaricus and Serrasalmus spp. were caught between October and February in lotic areas; whereas P. squamosissimus occurs in all sampled areas, with peak of capture in January. Hypophthalmus edentatus, H. aff. malabaricus, Serrasalmus spp. and B. stramineus were the taxa that most contributed to structure the assemblages temporally and spatially, and their abundances were influenced by the interaction of several environmental variables.

MAKRAKIS, Maristela Cavicchioli; NAKATANI, Keshiyu; BIALETZKI, Andréa; GOMES, Luiz Carlos; SANCHES, Paulo Vanderlei; BAUMGARTNER, Gilmar. Relationship between gape size and feeding selectivity of fish larvae from a Neotropical reservoir. Journal of Fish Biology, London, v.72, no.7, p.1690-1707, 2008. Larvae feeding selectivity of Iheringichthys labrosus, Hypophthalmus edentatus and Plagioscion squamosissimus was assessed, examining the role of mouth gape in prey selection. Fish larvae were sampled in the Itaipu Reservoir (Brazil Paraguay). Iheringichthys labrosus and H. edentatus larvae, with small and similar gape sizes, exhibited slightly different diets; I. labrosus preferred cladocerans (Bosmina hagmanni, Bosmina huauriensis and Bosminopsis deitersi) and the rotifer Brachionus calyciflorus. Hypophthalmus edentatus, however, primarily ingested the cladocerans B. hagmanni, Ceriodaphnia cornuta, Daphnia gessneri and Diaphanosoma spinulosum. Plagioscion squamosissimus, with a greater gape size, preferred Calanoida. The mechanistic processes that determine food selectivity of fish larvae in temperate aquatic systems were similar in the Neotropical system. The trophic spectrum of these species is characterized by small- to intermediate-sized prey. Plagioscion squamosissimus larvae, which have larger mouths, exploit primarily larger prey differing from the most abundant species or size classes; consequently, their diet is quite different from I. labrosus larvae and modestly similar to H. edentatus larvae, opportunistic feeders that they eat more abundant prey.

Fish diversity loss is threatened by the construction of dams as they prevent the regular natural dispersal among populations. Thus, conservation of key riverine habitats for fish reproduction may be essential for the recruitment of new native species of fish. The present study aimed to identify key habitats for fish spawning and early development in the Paranapanema River basin, as well as to determine the taxonomic composition, reproductive and life-history strategy, and to report spatial distribution of eggs, larvae and juveniles. The importance of lagoons, tributaries, and sub-tributaries was evaluated in the Paranapanema River basin between October 2012 and March 2013. Eggs and larvae samples were collected at dawn and dusk with conical plankton nets (0.5 mm mesh size), whereas juveniles were captured during the day with seine and sieve (0.5 cm mesh size). A total of 547 eggs, 904 larvae and 1 228 juveniles were captured. We observed that 2 larvae and 288 juveniles of non-migratory species, parental care, and equilibrium life-history strategy, predominated in lagoons and tributaries. On the other hand, 13 larvae and 60 juveniles of short migratory distance, no parental care, and periodic life-history strategy predominated in sub-tributaries. The highest densities of eggs were recorded in tributaries and sub-tributaries (Tukey’s test, P = 0.001 and P = 0.03, respectively), and the highest densities of larvae were recorded for lagoons and tributaries (P = 0.005 and P = 0.0001, respectively). Captures of eggs and larvae were higher at night; while the highest catches per unit effort of juveniles were recorded for tributaries and sub-tributaries. Fish species that adopt different life-history strategies can use diverse types of habitats during the early stages. Lagoons, tributaries and sub-tributaries of the Paranapanema River play different roles in the reproductive success of fish fauna in a heavily modified basin. The preservation of spawning and nursery areas trapped between reservoirs is necessary for Neotropical fish species recruitment and survival. Rev. Biol. Trop. 66(2): 605-621. Epub 2018 June 01. Resumen Los riesgos de pérdida de diversidad de peces aumentan con la construcción de represas, ya que impide la dispersión de individuos entre las poblaciones. Por lo tanto, la conservación del habitat ribereño clave para la reproducción de peces puede ser esencial para el reclutamiento de nuevos individuos de especies nativas. El presente estudio tiene como objetivo identificar hábitats clave para el desove y el desarrollo temprano de peces en la cuenca del río Paranapanema, así como determinar la composición taxonómica, la estrategia reproductiva y la historia de vida, y reportar la distribución espacial de huevos, larvas y juveniles. Se evaluó la importancia de lagunas, afluentes y subafluentes en la cuenca del río Paranapanema entre octubre de 2012 y marzo de 2013. Se recogieron muestras de huevos y larvas al amanecer y al atardecer con redes de plancton cónico (tamaño de malla de 0,5 mm), mientras que los juveniles fueron capturados durante el día con redes de cerco y tamiz (tamaño de malla de 0,5 cm). Se capturaron un total de 547 huevos, 904 larvas y 1 228 juveniles. Como resultado fue observado que 2 larvas y 288 juveniles de especies no migratorias, cuidado parental y estrategia de vida de equilibrio son predominantes en lagunas y afluentes. Por otro lado, 13 larvas y 60 juveniles de espécies migratorias de corta distancia, sin cuidado parental y estrategia de vida periódica predominaron en subafluentes. Se registraron las densidades más altas de huevos para afluentes y subafluentes (Prueba de Tukey, P = 0.001 y P = 0.03, respectivamente), y se registraron las densidades más altas de larvas para las lagunas y afluentes (P = 0.005 y P = 0.0001, respectivamente). Las capturas de huevos y larvas eran más altas por la noche. Las mayores capturas por unidad de esfuerzo de juveniles se registraron para los afluentes y subafluentes. Las especies de peces que adoptan diferentes estrategias de historia de vida pueden utilizar diversos tipos de hábitats durante las primeras etapas. Lagunas, afluentes y subafluentes del río Paranapanema desempeñan diferentes papeles en el éxito reproductivo de la fauna de peces en una cuenca fuertemente modificada. La preservación de áreas de desove y cría atrapadas entre el embalse es necesaria para el reclutamiento de especies de peces neotropicales.

Fish diversity loss is threatened by the construction of dams as they prevent the regular natural dispersal among populations. Thus, conservation of key riverine habitats for fish reproduction may be essential for the recruitment of new native species of fish. The present study aimed to identify key habitats for fish spawning and early development in the Paranapanema River basin, as well as to determine the taxonomic composition, reproductive and life-history strategy, and to report spatial distribution of eggs, larvae and juveniles. The importance of lagoons, tributaries, and sub-tributaries was evaluated in the Paranapanema River basin between October 2012 and March 2013. Eggs and larvae samples were collected at dawn and dusk with conical plankton nets (0.5 mm mesh size), whereas juveniles were captured during the day with seine and sieve (0.5 cm mesh size). A total of 547 eggs, 904 larvae and 1 228 juveniles were captured. We observed that 2 larvae and 288 juveniles of non-migratory species, parental care, and equilibrium life-history strategy, predominated in lagoons and tributaries. On the other hand, 13 larvae and 60 juveniles of short migratory distance, no parental care, and periodic life-history strategy predominated in sub-tributaries. The highest densities of eggs were recorded in tributaries and sub-tributaries (Tukey’s test, P = 0.001 and P = 0.03, respectively), and the highest densities of larvae were recorded for lagoons and tributaries (P = 0.005 and P = 0.0001, respectively). Captures of eggs and larvae were higher at night; while the highest catches per unit effort of juveniles were recorded for tributaries and sub-tributaries. Fish species that adopt different life-history strategies can use diverse types of habitats during the early stages. Lagoons, tributaries and sub-tributaries of the Paranapanema River play different roles in the reproductive success of fish fauna in a heavily modified basin. The preservation of spawning and nursery areas trapped between reservoirs is necessary for Neotropical fish species recruitment and survival. Rev. Biol. Trop. 66(2): 605-621. Epub 2018 June 01.

Fish larvae and adults are morphologically distinct from each other and have different ecological requirements. Research on the dynamics of ichthyoplankton provides valuable information about the early stages of the life cycle of fish. This study analyzed the temporal and spatial distribution of the larval stages of three migratory species - Salminus brasiliensis (Cuvier, 1816), Prochilodus lineatus (Valenciennes, 1836) and Pseudoplatystoma corruscans (Agassiz, 1829) - to identify possible spawning areas in the last lotic remnant of the upper Paraná River, in the Brazilian territory. A total of 26 points were sampled monthly from October 2003 to November 2004. The PERMANOVA detected significant differences between the months only for S. brasiliensis (Pseudo-F = 3.88, p = 0.0021) and P. corruscans (Pseudo-F = 3.35, p = 0.004). Among the environmental variables, temperature was the most important and the Mantel test detected a significant correlation between temperature and the densities, only for P. lineatus (r = 0.09, p = 0.03). The species in our data chose for spawning tributaries that are not dammed, of which most are outside conservation areas. Therefore, recruitment, maintenance and possible actions aiming to recover the stocks of these species are dependent on the conservation of tributaries and floodplain lakes in the region, in addition to monitoring to prevent fishing during the reproductive period.

The effect of fish larvae on the diel vertical migration of the zooplankton community was investigated in two tropical lakes, Finado Raimundo and Pintado lakes, Mato Grosso do Sul State, Brazil. Nocturnal and diurnal samplings were conducted in the limnetic region of each lake for 10 consecutive months from April 2008 to January 2009. The zooplankton community presented a wide range of responses to the predation pressure exerted by fish larvae in both environments, while fish larvae showed a typical pattern of normal diel vertical migration. Our results also demonstrated that the diel vertical migration is an important behaviour to avoid predation, since it reduces the spatial overlap between prey and potential predator, thus supporting the hypothesis that vertical migration is a defence mechanism against predation.

Aim: To analyze temporal distribution of larvae and juveniles and the early development and of Moenkhausia cf. gracilima. Methods Samples were taken quarterly in twenty-five sites in the upper Paraná River floodplain between August 2013 and May 2015. The samples were taken under the water surface at night using 0.5 mm mesh plankton nets. In the laboratory, samples were sorted, identified and separated into larval (preflexion, flexion and postflexion) and juvenile periods. Results A total of 248 individuals was collected, mainly in the Saraiva Lagoon, suggesting that the entire life cycle of this species occurs in this environment. The reproductive period takes place between December and April, since the postflexion larvae were found until May. However, the occurrence of juveniles between February and May indicates probable batch spawning. Among the 95 individuals used for ontogenic description, 82 were larvae and 13 juveniles. Larvae may be characterized by irregular pigmentation in the upper region of the head, mouth, and body, increasing throughout development; upper lobe of the caudal fin more pigmented than the lower lobe, only visible in postflexion larvae; terminal mouth; anal opening located anterior to the median region of the body and total number of myomers ranging from 34 to 40 (15 to 20 pre and 16 to 23 postanal), while juveniles have characteristics similar to adults. The total number of fin rays is: P. 11-16, V. 7-11, D, 9-11 and A. 21-23. Conclusions According to the distribution of developmental periods it is possible to conclude that this species reproduces in the summer, preferably in lagoons. Growth analysis indicated important alterations in larval morphology (metamorphosis) that may be associated with the ecomorphological characteristics of the species. The morphological separation of larvae of M. cf. gracilima from other larvae of small characids, especially at preflexion and flexion stages may be complicated by the overlap of traits, suggesting the use of other variables, mainly morphometric, for the separation of the species. Resumo Objetivo: Analisar a distribuição temporal de larvas e juvenis e o desenvolvimento inicial de Moenkhausia cf. gracilima. Métodos Foram amostrados trimestralmente vinte e cinco estações distribuídas na planície de inundação do alto rio Paraná entre agosto de 2013 e maio de 2015. As coletas foram na subsuperfície, no período noturno, utilizando redes de plâncton com malha 0,5 mm. Em laboratório, as amostras foram triadas, identificadas e separadas em períodos larval (pré-flexão, flexão e pós-flexão) e juvenil. Resultados Foram capturados 248 indivíduos, sendo a maioria na Lagoa Saraiva, sugerindo que todo o ciclo de vida desta espécie aconteça neste ambiente, e que o período reprodutivo ocorre entre dezembro e abril, uma vez que larvas em pós-flexão foram encontradas até maio. A ocorrência de juvenis entre fevereiro e maio indica provável desova parcelada. Entre os 95 indivíduos utilizados na descrição ontogênica, 82 eram larvas e 13 juvenis. As larvas podem ser caracterizadas pela pigmentação irregular na região superior da cabeça, na boca e no corpo, aumentando ao longo do desenvolvimento; lobo superior da nadadeira caudal mais pigmentado do que o inferior, só visível em larvas em pós-flexão; boca em posição terminal, abertura anal localizada anteriormente à região mediana do corpo e número total de miômeros variando de 34 a 40 (15 a 20 pré e 16 a 23 pós-anal), enquanto os juvenis apresentam características semelhantes ao adulto. O número de raios das nadadeiras é: P. 11-16, V. 7-11, D, 9-11 e A. 21-23. Conclusões De acordo com a distribuição dos períodos de desenvolvimento, é possível concluir que esta espécie se reproduz no verão, de preferência em lagoas. A análise do crescimento indicou alterações importantes na morfologia larval (metamorfoses) que podem estar associadas às características ecomorfológicas da espécie. A separação morfológica das larvas de M. cf. gracilima de outras larvas de caracteres pequenos, especialmente nos estágios de preflexão e flexão, pode ser complicado pela sobreposição de traços, sugerindo o uso de outras variáveis, principalmente morfométricas, para a separação das espécies.