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Producción Científica, 1.Most freshwater fish need to move freely through rivers to complete their lifecycles. Thus, river barriers (e.g. dams, culverts and gauging stations) may delay,hinder or even block their longitudinal movements, affecting fish conservation.The most widespread solution to allow upstream fish migration are fishways,whereas downstream migration is basically facilitated through spillways, turbinesor specific solutions such as bypass systems.2. So far, studies and scientific discussions concerning bidirectional movementsthrough fishways are scarce and focused on large dams and reservoirs, mainlywith large migratory species such as salmonids, rather than smaller facilities andlesser known species.3. This study investigated bidirectional movements through a small run-of-the-riverhydropower plant with a pool-and-orifice type fishway, using the Iberian barbel(Luciobarbus bocagei), a potamodromous cyprinid, as the target species. Passiveintegrated transponder and radio tracking data were collected over 4 years andcombined to characterize upstream and downstream movements. The studyfocused primarily on fish movements through the fishway, but also estimated themultiple associated routes of passage.4. The results show diverse fish movements with inter- and intra-annual variability,with several individuals performing bidirectional movements and even some fishreturning over the years.5. The documented movements and observations indicate that fishways can serveas an effective bidirectional migration corridor for fish, potentially enhancing theconservation efforts for potamodromous species. This study supports thedecision to use fishways as an overall mitigation tool to reduce the impact ofsmall hydropower facilities on fish., European Union’s Horizon 2020 research and innovation program. grant agreement no.727830, European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no.101032024

The seasonal pattern and the composition of downstream drift of fish eggs and larvae through the fish ladder of the Porto Primavera dam, located in the Upper Parana River, Brazil, were studied. Add...

The land use and occupation in watersheds directly influences the water resources, and the vegetation cover is a crucial factor for water maintenance. The objective of this study was to characterize the land use and occupation in nine watersheds of the Lower Iguaçu River (Andrada, Monteiro, Gonçalves Dias, Floriano, Silva Jardim, Cotejipe, Sarandi, Capanema and Santo Antônio sub-basin rivers), using the classification from satellite images. The classification area obtained high accuracy (Kappa coefficient of 99.4 to 99.9%). The Floriano River sub-basin presented the highest degree of environmental preservation, followed by Silva Jardim and Gonçalves Dias River sub-basins, fully or partially inserted in Iguaçu National Park. Monteiro and Sarandi river sub-basins showed the smallest areas of vegetation, and Capanema, Cotejipe, Andrada and Santo Antônio River sub-basins exhibited an intermediate condition. This tendency was verified by the cluster analysis. These results can serve as a baseline for planning, monitoring and management of this area, environmental modeling, conservation of water resources, biodiversity, and environmental services. El uso y la ocupación de la tierra en las cuencas hidrográficas influyen directamente en los recursos hídricos y la cubierta vegetal es un factor determinante para el mantenimiento del agua. El objetivo de este estudio fue caracterizar el uso y la ocupación del suelo en nueve cuencas del bajo Iguaçú (ríos Andrada, Monteiro, Gonçalves Dias, Floriano, Silva Jardim, Cotejipe, Sarandi, Capanema y Santo Antônio), utilizando la clasificación de uso y ocupación de la tierra a partir de imágenes de satélite. La clasificación de áreas obtuvo una buena precisión (coeficiente Kappa de 99,4 a 99,9%) y la cuenca del Floriano fue la que presentó el mayor grado de preservación ambiental, seguida por las cuencas de los ríos Silva Jardim y Gonçalves Dias, insertas total o parcialmente en el Parque Nacional de Iguaçú. Las cuencas de los ríos Monteiro y Sarandi poseen las menores áreas de vegetación y los ríos Capanema, Cotejipe, Andrada y Santo Antônio se encuentran en una condición intermedia. La misma tendencia se verificó mediante el análisis de conglomerados. Los resultados pueden servir de base para la planificación, el seguimiento y la gestión de la zona, la elaboración de modelos ambientales, la conservación de los recursos hídricos, la biodiversidad y los servicios ambientales. O uso e ocupação da terra em bacias hidrográficas influencia diretamente os recursos hídricos, sendo a cobertura vegetal um fator determinante para a conservação dos rios. O objetivo deste estudo foi caracterizar o uso e ocupação do solo em nove bacias do baixo rio Iguaçu (rios Andrada, Monteiro, Gonçalves Dias, Floriano, Silva Jardim, Cotejipe, Sarandi, Capanema e Santo Antônio), utilizando a classificação do uso e ocupação da terra a partir de imagens de satélite. A classificação da área obteve boa acurácia (coeficiente Kappa de 99,4 a 99,9%) e a bacia do Floriano foi a que apresentou o maior grau de preservação ambiental, seguida pelas bacias dos rios Silva Jardim e Gonçalves Dias, integral ou parcialmente inseridas no Parque Nacional do Iguaçu. As bacias dos rios Monteiro e Sarandi possuem as menores áreas da classe vegetação e os rios Capanema, Cotejipe, Andrada e Santo Antônio, encontram-se em uma condição intermediária. A mesma tendência foi verificada pela análise de agrupamento. Os resultados podem servir de linha de base para o planejamento, monitoramento e manejo da área, modelagem ambiental, conservação dos recursos hídricos, da biodiversidade e dos serviços ambientais.

The population structure and reproductive biology of the surubim of Iguacu, Steindachneridion melanodermatum, a large endemic and endangered catfish from Iguacu River basin, were evaluated. In total, 182 specimens of this species were sampled from September 2010 to December 2016 in the Lower Iguacu River, including some tributaries. The determination of the cycle and reproductive period was undertaken by assessing the mean variation in the values of the gonadosomatic index (GSI) of females and males, as well as by the frequency distribution of the stages of gonadal development on the basis of macroscopic and microscopic analyses. The total length and bodyweight ranged from 21 to 102cm and from 82.8 to 15670g respectively. The reproductive period of this species was from June to September (winter and early spring), and may extend until November, with GSI peaking in August for males and September for females. The size at first maturation (L50) corresponded to 39.5cm for females and 43.9cm for males. Spawning in this species was associated with lower water temperatures, and high discharge and dissolved oxygen concentration. Our findings are crucial in assisting the development of effective measures and specific criteria for the conservation of this endangered species.

Conservation of fish assemblages in severely impounded rivers has often focused on providing longitudinal and lateral connectivity along the main stem. Less attention has been given to tributaries, some of which remain unimpounded. This study shows that the biodiversity of ichthyoplankton in tributaries to the largest reservoir in the Parana River, Brazil, is similar to that of tributaries of the few remaining unimpounded stretches of the Parana River. Annual and seasonal variability in discharge within and among tributaries attracts and supports a diverse mix of species in each spawning season. Tributaries enrich the fish biodiversity of the entire system by providing a variety of environmental conditions, access to spawning habitat, refugia for early life stages, and by promoting ecological heterogeneity. Thus, tributaries can mitigate the adverse influence of an impounded main stem. Tributaries also support populations of endangered and threatened species. A focus on tributaries offers conservation alternatives that are more feasible given the scale and large number of impoundments constructed on the main stem. Conservation in the main stem may focus on maintaining passage through dams and access to large floodplains. Conversely, in tributaries conservation may focus on managing the quality of inflows from catchments, preserving suitable instream habitats and flows, and preserving access to smaller but more numerous floodplains.

Brown trout uses river flow and thermal regimens as main stimuli for initiating and maintaining behavioral reactions such as migration and spawning. Therefore, anthropogenic alterations on these factors may have strong impacts on its populations. The aim of this work is to understand these consequences by assessing potamodromous brown trout movements in the past and present, and to model future responses. For this, brown trout movements in a fishway in the Marin River (Bidasoa basin, Northern Iberian Peninsula) have been monitored from 2008 to 2017. Random forest regression has been used to assess the influence of environmental variables on brown trout movements and to model the response under hypothetical climatic and hydrological scenarios. Results show that brown trout uses the fishway during the whole year, with more upstream movements during the spawning season. The model is able to predict accurately the timing and number of migrants. Its use under hypothetical climate change and flow regulation scenarios shows a delay in the migration time. Therefore, modelling using large time series can be a powerful tool to define management and conservation strategies and prepare compensation measures for future scenarios.

Many fish passes have been built across the world in recent years. This study analyses the performance of a modified type of pool and weir fishway with two access branches, using passive integrated transponder telemetry. A circum‐Mediterranean barbel, Luciobarbus bocagei (Steindachner, 1864), was chosen as the target species. Both hydraulic values (flow and volumetric energy dissipation) and biological parameters (attraction, entrance and passage success) were measured in the fishway, these being related to the environmental variables affecting upstream fish movement. Flow discharge, water temperature and atmospheric pressure were important for fish entering the fishway. There was no preference between path routes, even though the main discharge was concentrated in the turbine channel. This type of fishway design could be an alternative for the conservation of fish populations where multiple fish approach options are possible.

Over the past few decades, South American Rivers, including the Parana River system, have been intensely impacted by dam constructions. To mitigate adverse impacts, fish passages were incorporated into two large dams on the Parana River (Itaipu and Porto Primavera) to reestablish longitudinal connectivity, which is very important for conserving populations of migratory fish species. The aim of this study was to estimate genetic diversity, population differentiation and gene flow, using microsatellites markers and mitochondrial haplotypes (d-loop), in populations of Prochilodus lineatus, a long distance migratory species commonly found in Parana River basin drainages. Samples were obtained from six locations in the Upper and Middle Parana River: Porto Primavera Reservoir, downstream of the Porto Primavera Reservoir, four tributaries of this reservoir (Pardo, Peixe, Verde and Aguapei Rivers) and in the Iguacu River, downstream of the Itaipu dam. High genetic diversity was observed in all samples, as expected for species with large population sizes and high migration rates. However, the influence of other factors, such as secondary contacts, fish passages and restocking were also suggested. In general, evidence of spatial population structuring was not found, even though there were two large dams in the study area. This could also be attributed to the brief period that has elapsed since the dams were built, the influence of migratory and reproductive patterns and the possible contributory effects of the fish passages. Furthermore, the absence of population structuring also corroborates existing information that emphasizes the importance of unimpeded tributaries for conserving migratory fish populations in fragmented watersheds.

Migratory fish species are the highly susceptible to environmental impacts as river fragmentation by dams and loss of habitats. For the implementation of reproduction habitat rehabilitation projects, information about the biotic characteristics of the spawning grounds are necessary. In this work, information of the geomorphological, hydrological and water quality characteristics of the spawning areas of migratory fishes distributed in several orders were reviewed and compared with Brazilian species. With the information found, we conclude that these studies on the spawning grounds of migratory fishes from the north hemisphere, are quite advanced, projecting a clear image of what environment in necessary for the reproduction. However in Brazil, they are still scarce, what precludes the delineation of management projects for the conservation of those species.

The feeding selectivity of laboratory-reared larvae of Rhamdia voulezi was assessed to investigate the preferred preys in early life stages. Three experiments were conducted at different larval development stages, starting soon after the absorption of the yolk sac (on fourth day after hatching – DAH), using zooplankton from fish ponds as food. Differences were detected in the patterns of prey selection among development stages. At first, the larvae prefer small preys, such as rotifers and cladocerans. Later, when they are more developed, they prefer to feed on large preys, such as copepods. On the fourth DAH, larvae in the pre-flexion and initial flexion stage strongly selected rotifers and cladocerans (Diaphanosoma spinulosum, D. brevireme, Moina sp., M. micrura and M. minuta). At the other stages, cladocerans continued to be strongly selected. However, on the eighth DAH, larvae in flexion stage selected less strongly copepods Argyrodiaptomus azevedoi, Metacyclops mendocinus and Termocyclops decipiens. On the tenth DAH, larvae in postflexion stage selected more strongly copepods Argyrodiaptomus furcatus, Notodiaptomus cf. spinuliferus and M. mendocinus. As larvae grow, they tend to specialize in feeding of a particular prey. Prey selection of R. voulezi larvae was based both on species and zooplankton size. The size of the zooplankton ingested was related to the mouth gape size of larvae.

This paper presents sprinting data from Iberian barbel (Luciobarbus bocagei) and northern straight-mouth nase (Pseudochondrostoma duriense), volitionally swimming against high velocity flows (1.5, 2.5 and 3 m s−1) in an open channel flume. Swimming endurance and speed greatly exceeded previously published observations with both species attaining swim speeds >20 body lengths s−1. Flow velocity was the primary variable limiting the distance both species were able to traverse. Barbel swam greater distances than nase at higher flow velocities, with longer individuals attaining greater distances than smaller ones. The results challenge established fish passage guidelines, suggesting that in some cases these species are capable of passing much higher velocities than was previously believed.

Gymnogeophagus setequedas is a rare and rheophilic species of tribe Geophagini, considered endangered in Brazilian red lists. Its previously known geographical distribution range was the Paraná River basin, in Paraguay, and a tributary of the Itaipu Reservoir in Brazil. Since its description no specimens have been collected in the original known distribution area. However, recent records of G. setequedas in the lower Iguaçu River, in a region considered highly endemic for the ichthyofauna, extended the known geographical distribution and may represent one of the last remnants of the species. The aim of this study was to estimate the genetic diversity and population structure of G. setequedas, using microsatellite markers and mitochondrial haplotypes, in order to test the hypothesis of low genetic diversity in this restricted population. Muscular tissue samples of 86 specimens were obtained from nine locations in the Lower Iguaçu River basin, between upstream of the Iguaçu Falls and downstream of the Salto Caxias Reservoir. Seven microsatellites loci were examined and a total of 120 different alleles were obtained. The number of alleles per locus (NA) was 17.429, effective alleles (NE) 6.644, expected heterozygosity (HE) 0.675, observed (HO) heterozygosity 0.592, and inbreeding coefficient (FIS) 0.128. Twelve haplotypes in the D-Loop region were revealed, with values of h (0.7642) and π (0.00729), suggesting a large and stable population with a long evolutionary history. Thus, both molecular markers revealed high levels of genetic diversity and indicated the occurrence of a single G. setequedas population distributed along a stretch of approximately 200 km. The pattern of mismatch distribution was multimodal, which is usually ascribed to populations in demographic equilibrium. Nevertheless, the construction of a new hydroelectric power plant, already underway between the Salto Caxias Reservoir and Iguaçu Falls, could fragment this population, causing loss of genetic diversity and population decline, and for this reason it is necessary to maintain the Iguaçu River tributaries and downstream area from the Lower Iguaçu Reservoir free of additional dams, to guarantee the survival of this species.

When engineers and ecologists face a fishway design, many issues need to be considered, the type of fishway being the first and foremost. It is an especially complex issue in areas with species whose migratory and swimming behavior are as yet poorly known as Mediterranean barbels. The present study focuses on the fish passage of two of the most common types of technical fishways: Vertical Slot (VS), and Submerged Notch with Bottom Orifice (SNBO). Both types were studied and compared in terms of ascent ability (as the success rate and transit time) and motivation (as the proportion of attempts and attempt rate), with Iberian barbel (Luciobarbus bocagei) as the target species. Ascent ability in VS and SNBO were similar. More than 90% of fish ascended the fishways successfully and the median transit time to ascend a total water height of 2.25 m was less than 23 min. Fish length had an effect on ascent time, with the biggest ones being faster. Motivation was greater for VS, although not seeming to have a relevant influence in the passage. These results support the use of VS and SNBO in areas with Iberian barbel and provide new data of fishways performance helping ecologists and engineers with their decision making, mainly in Mediterranean areas with similar habitats and species.

Regulation of rivers by dams transforms previously lotic reaches above the dam into lentic ones and limits or prevents longitudinal connectivity, which impairs access to suitable habitats for the reproduction of many migratory fish species. Frequently, unregulated tributaries can provide important habitat heterogeneity to a regulated river and may mitigate the influence of impoundments on the mainstem river. We evaluated the importance of tributaries to spawning of migratory fish species over three spawning seasons, by comparing several abiotic conditions and larval fish distributions in four rivers that are tributaries to an impounded reach of the Upper Parana River, Brazil. Our study confirmed reproduction of at least 8 long-distance migrators, likely nine, out of a total of 19 occurring in the Upper Parana River. Total larval densities and percentage species composition differed among tributaries, but the differences were not consistent among spawning seasons and unexpectedly were not strongly related to annual differences in temperature and hydrology. We hypothesize that under present conditions, densities of larvae of migratory species may be better related to efficiency of fish passage facilities than to temperature and hydrology. Our study indicates that adult fish are finding suitable habitat for spawning in tributaries, fish eggs are developing into larvae, and larvae are finding suitable rearing space in lagoons adjacent to the tributaries. Our findings also suggest the need for establishment of protected areas in unregulated and lightly regulated tributaries to preserve essential spawning and nursery habitats. Copyright © 2014 John Wiley & Sons, Ltd.

O objetivo deste estudo foi descrever o desenvolvimento embrionário, larval e juvenil da jurupoca, Hemisorubim platyrhynchos (Valenciennes, 1840), bem como as mudanças nos padrões de crescimento alométrico durante a ontogenia inicial da espécie. Um total de 90 ovos, 210 larvas e 24 juvenis provenientes de reprodução induzida foram analisados quanto a variáveis morfométricas e merísticas, além do coeficiente de crescimento alométrico em relação à cabeça, tronco e cauda durante o período larval e juvenil inicial. Os ovos apresentaram diâmetro médio de 1,74 mm, espaço perivitelino amplo (21,29%), com média de 0,37 mm, e diâmetro médio do vitelo de 1,08 mm. O comprimento padrão (CP) das larvas variou de 3,47 a 11,85 mm, com a maioria das medidas apresentando aumento proporcional ao longo do desenvolvimento. O número total de miômeros variou de 40 a 46 (pré-anal=15-17 e pós-anal=24-30). As larvas iniciais de H. platyrhynchos apresentam pigmentação na cabeça e na região ântero-ventral do corpo (anterior e posterior do saco vitelino). No estágio de pós-flexão, a pigmentação se intensifica, distribuindo-se na região dorsal da cabeça, formando uma faixa longitudinal que se estende do focinho ao opérculo, assim como uma faixa transversal, de um flanco a outro, passando pela região anterior da nadadeira dorsal, com máculas distribuídas ao longo do corpo nos juvenis (CP=19,5-49,09 mm). Nos primeiros estágios de desenvolvimento larval, a cabeça e a cauda crescem muito mais rapidamente do que o tronco, o que indica prioridades relacionadas à alimentação e natação, as quais posteriormente tendem à isometria, com um crescimento rápido do tronco nos juvenis iniciais. This study aimed to describe the initial stages of development of the Pothole Shovelnose Catfish, Hemisorubim platyrhynchos (Valenciennes, 1840), as well as changes in the allometric growth pattern during early ontogeny. A total of 90 eggs 210 larvae, and 24 juveniles from hatching were analyzed for morphometric and meristic variables, and for besides the allometric growth coefficient in relation to head, trunk, and tail during larval and initial juvenile period. The eggs presented 1.74 mm of mean diameter; ample vitelline space (21.29%) with mean of 0.37 mm; and the average diameter of the yolk was 1.08 mm. The standard length (SL) of the larvae ranged from 3.47 to 11.85 mm, with most measurements a presenting proportional increase throughout development. The total number of myomeres ranged from 40 to 46 (pre-anal=15-17 and post-anal=24-30). The early larvae of H. platyrhynchos present pigmentation in the head and in the anteroventral region of the body (anterior and posterior regions of the yolk sac). The pigmentation intensifies in the post-flexion stage along the dorsal region of the head, forming a longitudinal strip extending from the snout to the operculum, as a transversal strip that goes from one side to the other, passing through the anterior region of the dorsal fin, with maculae distributed throughout the body in juveniles (SL=19.5-49.09 mm). In the early stages of larval development, the head and tail grow much faster than the trunk, indicating priorities related to food and swimming, which tend to isometry, with fast growth of the trunk in early juveniles.

O objetivo deste trabalho foi caracterizar a dieta e a morfologia do trato digestório do linguado, Catathyridium jenynsii (Günther, 1862) (Achiridae), em seus estágios iniciais de vida. Para análise do trato digestório, foi utilizado um exemplar de cada estágio larval, de pré-flexão até pós-flexão, e juvenil. Um total de 256 larvas e 16 juvenis, pertencentes a cinco classes de comprimento padrão, foi analisado quanto à dieta. Os dados foram coletados no reservatório de Itaipu, rio Paraná, Brasil, de setembro/2001 a março/2002 e setembro/2002 a fevereiro/2003. Para análise dos dados, foram aplicados os métodos de ocorrência e numérico para a determinação da frequência de ocorrência e numérica de cada item alimentar nas diferentes classes de comprimento padrão. A região anterior do trato digestório de C. jenynsii, começou a diferenciar-se em estômago partir de 4,70 mm CP (não apresentou cecos pilóricos). Desde o estágio de pré-flexão, verificou-se três dobras intestinais e várias estrias no trato digestório. A análise da dieta revelou que as larvas menores (classe 1) apresentaram uma dieta distinta, com dominância de cladóceros (especialmente Bosmina hagmanni e Bosminopsis deitersi). Para a classe 2, o copépodo Notodiaptomus sp. foi importante tanto em número quanto em ocorrência, entretanto B. hagmanni, ainda teve participação significativa na dieta. Já as larvas maiores (classes 3, 4) e juvenis (classe 5) apresentaram uma dieta similar, consumindo principalmente os copépodos (Notodiaptomus sp.). Portanto, neste estudo as larvas de C. jenynsii podem ser consideradas zooplanctívoras, já que em todos os estágios de desenvolvimento, cladóceros e copédodos dominaram a dieta. As alterações na dieta acompanharam as modificações morfológicas dos estágios iniciais de C. jenynsii. The objective of this study was to characterize the diet and digestive tract morphology of flounder, catathyridium jenynsii (günther, 1862) (achiridae), in its early stages of life. for analysis of the digestive tract, we used a specimen of each larval stage, pre-flexion to post-flexion, and juvenile. a total of 256 larvae and 16 juveniles, belonging to five classes of standard length was analyzed for diet. data were collected in the itaipu reservoir, paraná river, brazil, from september, 2001 to march, 2002, and from september, 2002 to february, 2003. the occurrence and numerical methods were applied for determining the occurrence frequency and numerical frequency of each food item in different standard length (sl) classes. the anterior digestive tract of c. jenynsii began to differentiate into the stomach at 4.70 mm sl (not presented pyloric caeca). since the stage of pre-flexion, there are three intestinal folds and a lot of grooves in the digestive tract. the dietary analysis showed that the smaller larvae (class 1) had a distinct diet, with dominance of cladocerans (mainly bosmina hagmanni and bosminopsis deitersi). for class 2, the copepod notodiaptomus sp. was important both in number and occurrence, however b. hagmanni also had significant importance in the diet. already the largest larvae (classes 3 and 4) and juveniles (class 5) showed a similar diet, consuming mainly copepods (notodiaptomus sp.). therefore, in this study, larvae of c. jenynsii can be considered zooplanktivore, since in all stages of development, copedods and cladocerans dominated the diet. changes in diet followed the morphological changes of the early stages of c. jenynsii.

The effects of the timing of first feeding on the point-of-no-return (PNR) and growth of laboratory reared silver catfish Rhamdia voulezi larvae were studied. The experiment began immediately after the complete absorption of the yolk sac, 3 days after hatching (DAH). The food was provided for the first time on 3rd, 4th, 5th, 6th, 7th, 8th, and 9th DAH. Zooplankton and newly-hatched Artemia spp. were used to feed the larvae. To evaluate the effect of food deprivation on growth, the standard length and weight of 594 larvae were assessed. Larval growth was significantly affected by the time of first exogenous feeding. The larvae fed from 3rd to 5th DAH showed a significantly higher development than those fed from 6th DAH. The larvae reached the PNR on 6th DAH. Survival and larval growth strongly depended on the timing of initial feeding. In order to avoid potential mortality by starvation and obtain good growth, the silver catfish larvae R. voulezi must establish successful initial feeding within 5 days after hatching. RESUMO Os efeitos do tempo da alimentação inicial sobre o ponto de não retorno (PNR) e o crescimento de larvas de jundiá Rhamdia voulezi foram estudados em condições laboratoriais. O experimento foi iniciado imediatamente após a completa absorção do saco vitelínico, 3 dias após a eclosão (DAE). O alimento foi fornecido pela primeira vez no 3o, 4o, 5o, 6o, 7o, 8o e 9o DAE. Zooplâncton e Artemia spp. recém-eclodida foram usados para a alimentação das larvas. Para avaliar os efeitos da privação alimentar sobre o crescimento, o comprimento padrão e peso de 594 larvas foram analisados. O crescimento larval foi significativamente afetado pelo tempo da primeira alimentação exógena. As larvas que receberam alimento do 3 o ao 5 o DAE apresentaram desenvolvimento significativamente maior que aquelas alimentadas mais tardiamente, a partir do 6 o DAE. As larvas alcançaram o PNR no 6 o DAE. A sobrevivência e o crescimento das larvas dependem do momento da alimentação inicial. Para evitar a mortalidade em massa e obter bom crescimento, as larvas de R. voulezi precisam estabelecer com sucesso a alimentação inicial até o 5 o dia após a eclosão.

The Piracema Canal is a complex 10-km fish pass system that climbs 120 m to connect the Parana River to the Itaipu Reservoir along the Brazil–Paraguay border. The canal was constructed to allow migratory fishes to reach suitable habitats for reproduction and feeding in tributaries upstream from the reservoir. The Piracema Canal attracted 17 of the 19 long-distance migratory species that have been recorded in the Parana River Basin and Paraguay–Parana Basin. However, the incidence of migratory fish decreased from downstream to upstream, with the pattern of decrease depending on species. Overall, 0.5% of the migratory fish that entered the Piracema Canal and segment 1, eventually were able to reach segment 5 and potentially Itaipu Reservoir. Ascension rate was examined relative to various physical attributes of canal segments; maximum water velocity emerged as the most influential variable affecting fish passage. Water velocity may be manipulated by controlling water discharge, and by re-engineering critical sections of the canal. Because the Itaipu Reservoir flooded a set of falls that separated two distinct biogeographical regions, facilitating fish movements through the Piracema Canal into the Itaipu Reservoir presents a management dilemma that requires deliberation in the context of the fish assemblages rather than on selected migratory species. Copyright © 2010 John Wiley & Sons, Ltd.

Summary A mark-recapture study was conducted in 1997-2005 to investigate movements of stocked pacu, Piaractus mesopota- micus, in the ParanaRiver Basin of Brazil, Paraguay, and Argentina. Fish raised in cages within the Itaipu Reservoir and in ponds were tagged externally (n = 2976) and released in the Itaipu Reservoir (53.2%) and bays of its major tributaries (46.8%). In total, 367 fish (12.3%) were recaptured. In all, 91% of the pacu moved away from the release site; upstream movements were more extensive than downstream movements. Pacu traveled upstream a maxi- mum of 422 km (average of 41.3 km) at a maximum rate of 26.4 km day )1 (av. 0.8). Downstream movements were limited in terms of number of individuals and distance moved. Fish released during the wet season moved farther than those released during the dry season, and feeding rather than spawning might have been the compelling reason for movement. Although fish passed downstream through dams, none of the marked fish were detected to have moved upstream through the passage facilities. Pacu showed move- ment patterns not radically different from those of other neotropical migratory species, but their migratory move- ments may not be as extensive as those of other large migratory species in the basin.

– We studied the migratory behaviour of armado, Pterodoras granulosus, in the Parana River Basin of Brazil, Paraguay and Argentina, during 1997–2005. This species invaded the Upper Parana River after upstream dispersal was facilitated when Itaipu Reservoir inundated a natural barrier. Fish were tagged (N = 8051) in the mainstems of the Yacyreta and Itaipu reservoirs, bays of major tributaries, the Parana River floodplain above Itaipu Reservoir, and below dams. In all, 420 fish were recaptured of which 61% moved away from the release area. Fish moved a maximum of 215 km (mean 42), and at a maximum rate of 9.4 km·day−1 (mean 0.6). Of the 256 armados that moved away from the release site, 145 moved upstream towards unimpounded stretches of the Parana River and 111 moved downstream into the reservoir and bays of its tributaries (maximum 150 km). Based on the observed migratory movements, we suspect that most of the reproductive output originates in tributaries to the reservoirs. The ability of this species to expand its range presents a conundrum by pitting fishery management interests against conservation needs. Maintenance of the important armado fisheries depends on the ability of the species to migrate freely to use spawning and nursery areas in reservoir tributaries and floodplains. However, its ability to migrate long distances can allow this non-native species the opportunity to invade most of the Upper Parana River.

Made available in DSpace on 2019-10-06T16:02:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 We evaluated the effectiveness of the fish ladder at Porto Primavera Dam in the severely regulated Upper Paraná River, for two Neotropical migratory fish species. Overall, 564 fish (448 Megaleporinus obtusidens and 116 M. piavussu) were PIT-tagged, released in upstream and downstream areas (on the left and right banks), and monitored continuously for 4 years. The fish performed two-way movements through the fish ladder, ascending from the tailrace and descending from the forebay. We registered entry into the fishway of 46 M. obtusidens (10.3%) individuals and only three M. piavussu (2.6%) individuals; therefore, all analyses were focussed on M. obstusidens. Entry proportion ranged from 0 to 48.1%, depending on the release site, and was greatest for fish released downstream near the fishway entrance. Entry times ranged from 3.0 to 384.0 days, and median times were 32.9 and 25.8 days for downstream and upstream respectively. Of fish that entered the fishway, passage percentages were 80% for fish released downstream and 100% for fish released upstream, and median transit times were 0.7 and 0.9 h respectively. Results suggest that if guidance and entry conditions can be improved, this fishway design holds promise as an effective solution for providing passage in both directions. Universidade Estadual Do Oeste Do Paraná Programa de Pos-Graduacao em Conservacao e Manejo de Recursos Naturais Jardim Universitário, Rua Universitária 2069 Universidade Estadual Do Oeste Do Paraná Grupo de Pesquisa em Tecnologia em Ecohidraulica e Conservacao de Recursos Pesqueiros e Hidricos Programa de Pós-Graduação em Recursos Pesqueiros e Engenharia de Pesca, Rua da Faculdade, 645 US Geological Survey-Leetown Science Center S.O. Conte Anadromous Fish Research Center Universidade Estadual Paulista-UNESP Engineering College of Ilha Solteira Department of Biology and Zootechny Fish Ecology Laboratory Universidade Estadual Paulista-UNESP Engineering College of Ilha Solteira Department of Biology and Zootechny Fish Ecology Laboratory

Migratory behaviour of selected fish species is described in the Parana River, Brazil-Argentina-Paraguay, to search for patterns relevant to tropical regulated river systems. In a 10 year mark-recapture study, spanning a 1425 km section of the river, 32 867 fishes composed of 18 species were released and 1083 fishes were recaptured. The fishes recaptured were at liberty an average 166 days (maximum 1548 days) and travelled an average 35 km (range 0-625 km). Cluster analysis applied to variables descriptive of movement behaviour identified four general movement patterns. Cluster 1 included species that moved long distances (mean 164 km) upstream (54%) and downstream (40%) the mainstem river and showed high incidence (27%) of passage through dams; cluster 2 also exhibited high rate of movement along the mainstem (49% upstream, 13% downstream), but moved small distances (mean 10 km); cluster 3 included the most fishes moving laterally into tributaries (45%) or not moving at all (25%), but little downstream movement (8%); fishes in cluster 4 exhibited little upstream movement (13%) and farthest downstream movements (mean 41 km). Whereas species could be numerically clustered with statistical models, a species ordination showed ample spread, suggesting that species exhibit diverse movement patterns that cannot be easily classified into just a few classes. The cluster and ordination procedures also showed that adults and juveniles of the same species exhibit similar movement patterns. Conventional concepts about Neotropical migratory fishes portray them as travelling long distances upstream. The present results broaden these concepts suggesting that migratory movements are more diverse, could be long, short or at times absent, upriver, downriver or lateral, and the diversity of movements can vary within and among species. The intense lateral migrations exhibited by a diversity of species, especially to and from large tributaries (above reservoirs) and reservoir tributaries, illustrate the importance of these habitats for the fish species life cycle. Considering that the Parana River is highly impounded, special attention should be given to the few remaining low-impact habitats as they continue to be targets of hydropower development that will probably intensify the effects on migratory fish stocks.

Este estudo teve como o objetivo avaliar a ocorrencia e distribuicao espacial e temporal de ovos e larvas de peixes, bem como, verificar a composicao e estrategias reprodutivas das especies ao longo do rio Aguapei - SP. As coletas foram realizadas mensalmente de outubro/2009 a marco/2010, atraves de arrastos horizontais na superficie da agua durante 10 minutos ao anoitecer utilizando rede de plâncton conico-cilindrica de 0,5mm de malha. Diferencas significativas na densidade media do ictioplâncton entre os locais e meses foram averiguadas atraves da Analise de Variância Unifatorial (ANOVA one-way). Um total de 1.626 ovos e 1.547 larvas foram coletados. A ANOVA aplicada nao demonstrou diferencas significativas nas densidades do ictioplâncton em relacao aos pontos amostrados. Com relacao a distribuicao temporal diferencas significativas p

Utilization of the fish ladder installed at the Engenheiro Sergio Motta Dam (also known as Porto Primavera) on the Paraná River, Southern Brazil, by long-distance migrating potamodromous species (sampling Protocol I), and ascending and descending movements (Protocol II) were evaluated. Three pools along the fish ladder (designated as lower, middle, and upper) were sampled monthly between December, 2004 and March, 2005 to determine the abundance of species in the ladder. The ascending and descending movements of the species in the ladder were also analyzed in the same period. In the samples for both protocols, 37 species representing 17 families and 5 orders (Characiformes, Siluriformes, Perciformes, Gymnotiformes, and Myliobatiformes) were recorded. Characiformes were represented by 21 species. Long- distance migratory species (11 species) predominated in the ladder (60% of the total number of individuals), with high abundance of Rhinelepis aspera (5645 individuals). For protocol I, mean abundance varied greatly among the months and pools, with lowest values in December and March for all pools, and highest in January for the lower pool due to high capture of R. aspera. Fish abundance declined from the lower to the upper pool, especially for R. aspera and Rhaphiodon vulpinus. For Protocol II, 17 species were recorded ascending the ladder, where Astyanax altiparanae and Leporinus friderici were the most abundant species (684 and 111 individuals, respectively). However, 18 species showed descending movements, with high captures of Metynnis maculatus and A. altiparanae (339 and 319 individuals, respectively). Twelve species (52%) moved in both directions, and among the seven migratory species sampled, four were recorded ascending and descending, and three species only ascending the ladder. The fish ladder appears to selectively favor species with high swimming capabilities. A discussion is presented on the requirements for future research on attraction to the fish ladder entrance, downstream movements, fish utilization of the ladder, and impacts on spawning and rearing habitat both upstream and downstream of the dam. A utilização da escada para peixes instalada na barragem Engenheiro Sergio Motta (também conhecida como Porto Primavera) no rio Paraná, no sudeste do Brasil, por espécies potamódromas de longa distância (protocolo I) e os movimentos ascendentes e descendentes (protocolo II) foram avaliados. Três tanques ao longo da escada para peixes (denominados como foz, meio e tomada) foram amostrados mensalmente entre dezembro de 2004 a março de 2005 para avaliar a abundância de espécies na escada. Os movimentos ascendentes e descendentes das espécies na escada foram analisados no mesmo período. Nas amostragens relativas aos protocolo I e II, foram capturadas 37 espécies representando 17 famílias e cinco ordens (Characiformes, Siluriformes, Perciformes, Gymnotiformes e Myliobatiformes). Os Characiformes foram representados por 21 espécies. Espécies migradoras de longa distância (11 espécies) predominaram (60% do total), com maior abundância de Rhinelepis aspera (5645 indivíduos). A abundância média variou entre os meses e tanques para o protocolo I, com menores valores em dezembro e março para todos os tanques, e maiores em janeiro no tanque foz, devido a maior captura de R. aspera. A abundância de peixes diminuiu do tanque foz para o tanque tomada, especialmente para R. aspera e Rhaphiodon vulpinus. Nas capturas relativas ao protocolo II, foram capturadas 17 espécies ascendendo a escada: Astyanax altiparanae e Leporinus friderici foram as mais abundantes (com 684 e 111 indivíduos, respectivamente). Entretanto, 18 espécies apresentaram movimentos descendentes, com elevadas capturas de Metynnis maculatus e A. altiparanae (339 e 319 indivíduos, respectivamente). Doze espécies apresentaram movimentos ascendentes e descendentes na escada, e das sete espécies migradoras amostradas, quatro apresentaram movimentos para cima e para baixo, e três espécies somente subiram. Esta escada para peixes parece favorecer seletivamente espécies com elevada capacidade de natação. As necessidades de pesquisas futuras para elucidar sobre a atratividade da escada, movimentos descendentes, utilização da escada pelos peixes e os impactos sobre as áreas de reprodução e criadouros, ambos a montante e jusante da barragem, são discutidos.