Distribution of diversity of fishes in an Andean fluvial network

Introduction: The distribution of freshwater fishes in the Colombian Andes results from the interaction between historical and recent factors. Currently, the Andean landscape is facing rapid transformation processes. However, the knowledge regarding species distribution and environmental requirements is advancing slower than the transformations underway in the fluvial networks. Objective: To understand the conformation of the fish assemblage in the middle and lower Cauca River basin, considering the local environmental context before the construction of the Ituango Dam, and quantifying β diversity and its two components (turnover and nestedness) amongst local fish communities. Methods: 58 localities were monitored during nine years (between February 2010 and November 2018), the period before the dam's operation. The species richness (α-diversity), species turnover (β-diversity), and assemblage composition were estimated for the given localities. Results: 114 species were recorded, representing ~ 49 % of the total richness of known species for the Magdalena basin. The richness distribution showed that the number of species varies among the aquatic environments. Swamps presented the most significant number of species, followed by the Cauca River, while streams had the lowest values of richness. The spatial analyses of β-diversity revealed a high variation component in the study area due to species replacement between the aquatic environments. Conclusions: The implementation of long-term monitoring allowed us to recognize that the Cauca River basin conserves a great variety of species-rich environments. The species turnover indicates a high proportion of endemism or multiple sites with unique species. Finally, our study will serve as a baseline to verify, over time, whether the dam's construction is associated with essential changes in the structure of fish communities.

Introducción: La distribución de los peces de agua dulce en los Andes colombianos es el resultado de la interacción entre factores históricos y recientes. Actualmente, el paisaje Andino enfrenta procesos de rápida transformación. Sin embargo, el conocimiento sobre la distribución de las especies y sus requerimientos ambientales no avanza tan rápido como las transformaciones en curso en las redes fluviales. Objetivo: Comprender la conformación del ensamble de peces en la cuenca media y baja del río Cauca, considerando el contexto ambiental local antes de la construcción de la represa de Ituango, y cuantificar la diversidad beta y sus dos componentes (recambio y anidamiento) entre las comunidades de peces locales. Métodos: Se analizaron 58 localidades durante nueve años (entre febrero 2010 y noviembre 2018), período previo a la operación de la represa. La riqueza de especies (diversidad α), el recambio de especies (diversidad β) y la composición del conjunto se estimaron para las localidades dadas. Resultados: Se registraron 114 especies, que representan ~ 49 % de la riqueza total de especies conocidas para la cuenca del Magdalena. La distribución de la riqueza mostró que el número de especies varía entre los ambientes acuáticos. Las ciénagas presentaron el mayor número de especies, seguidas por el río Cauca, mientras que las quebradas presentaron los valores más bajos de riqueza. Los análisis espaciales de la diversidad β revelaron un alto componente de variación en el área de estudio debido al reemplazo de especies entre los ambientes acuáticos. Conclusiones: La implementación del monitoreo a largo plazo permitió reconocer que la cuenca del río Cauca conserva una gran variedad de ambientes ricos en especies. El recambio de especies indica una alta proporción de endemismo o múltiples sitios con especies únicas. Finalmente, nuestro estudio servirá como línea base para verificar, con el tiempo, si la construcción de la represa está asociada con cambios esenciales en la estructura de las comunidades de peces.

Microplastics pollution in the Yellow River basin: current status and control strategy / 生物工程学报

Microplastics pollution has attracted worldwide attention. Compared with the status quo of microplastics pollution in marine environment and other major rivers and lakes, the relevant data of the Yellow River basin is relatively inadequate. The abundance, types, and spatial distribution characteristics of microplastic pollution in the sediments and surface water of the Yellow River basin were reviewed. Meanwhile, the status of microplastic pollution in the national central city and Yellow River Delta wetland was discussed, and the corresponding prevention and control measures were put forward. The results showed that the spatial distribution of microplastics pollution in sediments and surface water of the Yellow River basin increased from upstream to downstream, especially in the Yellow River Delta wetland. There are obvious differences between the types of microplastics in sediment and surface water in the Yellow River basin, which is mainly related to the materials of microplastics. Compared with similar regions in China, the microplastics pollution levels in national key cities and national wetland parks in the Yellow River basin are in the medium to high degree, which should be taken seriously. Plastics exposure through various ways will cause serious impact on aquaculture and human health in the Yellow River beach area. To control microplastic pollution in the Yellow River basin, it is necessary to improve the relevant production standards, laws and regulations, and improve the capacity of biodegradable microplastics and the degradation capacity of plastic wastes.

Genetic variability of cocoa from the amazon basin: implications for genetic conservation

The cocoa and chocolate production chain involves US$60 billion annually and three million farmers around the world, in an area exceeding nine million hectares. The use of wild germplasm will enable to generate new disease- and pest-resistant cultivars and ability to adapt to changing environments. Here we evaluated 145 cocoa accessions, originated from nine Amazonian basins, based on eight fruit traits. Univariate anova showed significant differences (p<0.05) for all traits. For seven traits, the variance component within basins was higher (81.5%, on average). Therefore, it is recommended that the collection of wild accessions prioritize a larger number of plants from a few populations of the most divergent basins. The multivariate analyses revealed a greater divergence between the Ji-Paraná-RO and Solimões/Amazonas-PA basins (27.69) and a greater similarity between Alien clones-PER and Solimões/Amazonas-AM (0.66) in relation to their populations. They also revealed that the accessions differentiation occurred according to the river basin system. These results allowed elucidate the genetic structure and distribution of cacao populations. In addition, strengthen the importance of collecting and conserving germplasm to preserve genetic resources.

An updated distribution list of Leptophlebiidae Banks, 1900 (Ephemeroptera: Insecta) for Piauí state / Uma lista de distribuição atualizada de Leptophlebiidae Banks, 1900 (Ephemeroptera: Insecta) para o estado do Piauí

Abstract Leptophlebiidae is the second most diverse family within Ephemeroptera, with species distributed across various States in Brazil, but with gaps in distribution records in others. Currently, nine species of Leptophlebiidae are recorded for the state of Piauí. Based on this information gap, the objective of this study was to present an updated species list of the family Leptophlebiidae new occurrence records and distributional sites for the state of Piauí, Brazil. By analyzing 447 specimens, we have significantly expanded our knowledge about the distribution of Leptophlebiidae species in the state of Piauí, increasing the recorded species from nine to 17. We have also added new occurrence records for six species and, for the first time, documented the presence of four genera. It is important to highlight that there is still an extensive area within the Cerrado and Brazilian semiarid regions where the occurrence of Ephemeroptera is unknown, confirming that the diversity in this area is underestimated and that knowledge of Ephemeroptera species and their distributions can expand with increased sampling efforts in the coming years, reducing the Linnean and Wallacean shortfall regarding this group. Our results also demonstrate the urgent need for inventories in the southern part of the state of Piauí, particularly in the sub-basins of the middle and upper Parnaíba river, which are considered suitable for monoculture expansion in Brazil.

Resumo Leptophlebiidae é a segunda família mais diversa de Ephemeroptera, com espécies distribuídas em vários estados do Brasil, mas com lacunas no registro de distribuição em outros. Por exemplo, no estado do Piauí tem registrado apenas nove espécies de Leptophlebiidae. Baseada nessa lacuna de informação, o objetivo deste estudo foi apresentar uma lista atualizada de espécies da família Leptophlebiidae, novos registros de ocorrência e sítios de distribuição para o estado do Piauí, Brasil. Ao analisar 447 exemplares, ampliamos significativamente nosso conhecimento sobre a distribuição das espécies de Leptophlebiidae no estado do Piauí, aumentando o número de espécies registradas de nove para 17. Também adicionamos novos registros de ocorrência para seis espécies e, pela primeira vez, documentamos a presença de quatro gêneros. Destacamos que ainda existe uma extensa área do Cerrado e semiárido brasileiro que se desconhece a ocorrência de Ephemeroptera, confirmando que a diversidade nessa área é subestimada e que o conhecimento sobre as espécies de Ephemeroptera e suas distribuições podem se expandir com o aumento do esforço amostral nos próximos anos, diminuindo as lacunas Lineana e Wallaceana sobre esse grupo. Nossos resultados também demonstram a necessidade emergencial de inventários no sul do Estado do Piauí, principalmente nas sub-bacias do médio e alto rio Parnaíba que é considerado adequado para a expansão da monocultura no Brasil.

Construction of a surveillance and early warning index system for schistosomiasis transmission risk along the middle and lower reaches of the Yangtze River basin / 中国血吸虫病防治杂志

Objective To establish a surveillance and early warning index system for schistosomiasis transmission risk along the middle and lower reaches of the Yangtze River basin, so as to provide insights into creation of a sensitive and highly efficient surveillance and early warning system for schistosomiasis. Methods National and international publications, documents, laws and regulations pertaining to schistosomiasis control were retrieved with keywords including schistosomiasis, surveillance, early warning and control interventions from 2008 to 2022, and a thematic panel discussion was held to preliminarily construct surveillance and early warning index system for schistosomiasis transmission risk along the middle and lower reaches of the Yangtze River basin. The index system was then comprehensively scored and screened using the Delphi method, and the weight of each index was determined using analytic hierarchy process and the modified proportional allocation method. In addition, the credibility of the Delphi method was evaluated using positive coefficient, authority coefficient, degree of concentration and degree of coordination of experts. Results Following two rounds of expert consultation, a surveillance and early warning index system for schistosomiasis transmission risk in endemic areas along the middle and lower reaches of the Yangtze River basin was preliminarily constructed, including 3 primary indicators, 9 secondary indicators and 41 tertiary indicators. The normalized weights of primary indicators epidemics, natural and social factors and comprehensive control were 0.639 8, 0.145 6 and 0.214 6, respectively, and among all secondary indicators, snail status (0.321 3) and schistosomiasis prevalence (0.318 5) had the highest combined weights, while social factors had the lowest combined weight (0.030 4). Of all tertiary indicators, human egg-positive rate (0.041 9), number of acute schistosomiasis cases (0.041 5), number of stool-positive bovine and sheep (0.041 1), and prevalence of Schistosoma japonicum in free-ranging livestock (0.041 1) had the highest combined weights. During two rounds of consultation, the positive coefficient of experts was both 100%, and the authority coefficient was both 0.9 and greater, while the coordination coefficients were 0.338 to 0.441 and 0.426 to 0.565 (χ2 = 22.875 to 216.524, both P values < 0.05). Conclusions The established surveillance and early warning index system for schistosomiasis transmission risk along the middle and lower reaches of the Yangtze River basin is of great scientific values and authority, which may provide insights into construction of the sensitive and highly efficient surveillance and early warning system for schistosomiasis in the context of low prevalence and low intensity of infection in China.

Effect of environmental characteristics on the diversity of aquatic macroinvertebrates in Andean rivers regulated for hydroelectric generation / Efecto de características ambientales en la diversidad de macroinvertebrados acuáticos en ríos andinos regulados para generación hidroeléctrica

Introduction: The Andes are characterized by an abundance of water resources and flows are frequently regulated by reservoirs for the generation of energy. The effects of regulation on aquatic macroinvertebrate communities are not well known in Colombia. Objective: To test the hypothesis that regulated currents have less macroinvertebrate diversity. Methods: We collected water and organism samples before, and after, the regulation of the Tafetanes, Calderas and Arenosa rivers, in Antioquia, Colombia, during various hydrological cycles (rain, transition and drought) and climatic phenomena (ENSO/El Niño Phenomenon) between 2016 and 2018. Results: We collected 53 214 individuals, from 165 taxa, mostly from the orders Ephemeroptera, Plecoptera, Trichoptera and Diptera (90 % of captures). Changes in diversity responded to spatial differences rather than to physicochemical variables: diversity was higher in non-regulated sites, regardless of the hydrological period or associated ENSO. Most species were found in all sampling sites, but abundance was higher in the site with the best habitat conservation status. Conclusion: The results support the hypothesis that physical barriers have effects on macroinvertebrate diversity at the local scale, however, the condition of adjacent habitats also seems to play an important role in preserving richness and abundance. The conservation of forest adjacent to the riverbed could mitigate the impacts of regulation.

Introducción: Los Andes se caracterizan por tener gran abundancia de recursos hídricos y las corrientes son frecuentemente reguladas por embalses para la generación de energía. Los efectos de la regulación en las comunidades de macroinvertebrados acuáticos no se conocen bien en Colombia. Objetivo: Probar la hipótesis de que las corrientes reguladas presentan menor diversidad de macroinvertebrados. Métodos: Recolectamos muestras de agua y organismos, antes y después de la regulación de los ríos Tafetanes, Calderas y La Arenosa, en Antioquia, Colombia, durante varios ciclos hidrológicos (lluvia, transición y sequía) y fenómenos climáticos (ENSO/Fenómeno de El Niño) entre 2016 y 2018. Resultados: Recolectamos 53 214 individuos, de 165 táxones, en su mayoría de los órdenes Ephemeroptera, Plecoptera, Trichoptera y Diptera (90 % de las capturas). Los cambios en la diversidad respondieron a las diferencias espaciales más que a las variables fisicoquímicas: la diversidad fue mayor en sitios no regulados, independientemente del periodo hidrológico o del ENSO. La mayoría de las especies se encontraron en todos los sitios de muestreo, pero su abundancia fue mayor en el sitio de mejor estado de conservación del hábitat. Conclusiones: Los resultados apoyan la hipótesis de que las barreras físicas tienen efectos sobre la diversidad de macroinvertebrados a escala local, sin embargo, el estado de los hábitats adyacentes también parece jugar un papel importante en la preservación de la riqueza y abundancia. La conservación del bosque adyacente podría mitigar los impactos generados por la regulación.

Localization and Distribution of Two Invasive Alien Species Eichhornia crassipes and Echinocloa pyramidalis in the Pool Malebo Eco-region, Democratic Republic of the Congo

Aim: To study the distribution of two invasive alien plants and associated plants as well as their distribution in the Malebo Pool eco-region. Methodology: The study was carried out by direct observation by circulating on a motorized canoe. Plant samples were randomly harvested (n=6) in August 2020 depends on the sites. Plant species identification was performed on the field, and those species of which the identification was difficult, were brought to the laboratory for proper identification according to APG III. Results: 19 species, including two Pteridophytes and 17 Angiosperms, belonging to 19 families and 12 orders were identified. The site of Molondo was the most diversified with 15 plant species, followed respectively by the sites of Mipongo (13 species), Japon (12 species) and Kingabwa (07 species). The plant species Ludwigia abyssinica A. Rich., Ipomoea aquatica Forsk, Eichhornia crassipes (Mart), Pistia stratiotes L, Echinochloa pyramidalis (Lam) and Salvinia molesta D.S. Mitchell were present in all four prospected sites. E. pyramidalis and E. crassipes constitute a serious threat for the environment and are source of erosion/loss of aquatic biodiversity. Physiologically, these species form a mono-specific carpet and eliminate native or autochthonous species of aquatic flora.Conclusions and Suggestions: The invasion of alien species is a consequence of human activities and a concern, as it affects all sectors of society. These plants can alter, disrupt, and degrade many ecosystem services like the disturbing of habitats and the alteration of the environmental and biological conditions around them. They can also reduce light and diversity of native aquatic plant species. Controlling invasive alien species is thus a challenge for the Congolese society. Political decision-makers are therefore invited to take appropriate measures for managing and protecting the local aquatic flora and valorize the invasive plants as potential medicinal remedy.

Educación ambiental mediada desde las ecologías sociocuturales para el abordaje del territorio en contextos escolares / Environmental education mediated from socio-cultural ecologies for the approach to territory in school contexts

RESUMEN Desde la perspectiva de las ecologías socioculturales, como campo emergente interdisciplinario, se puede enriquecer de manera alternativa y complementaria la educación ambiental, puesto que permite un acercamiento comprensivo a las dinámicas de ocupación humana y las transformaciones en un territorio concreto desde una mirada histórica, política y sociocultural. Esta investigación, se llevó a cabo en el contexto territorial de la cuenca del río Quindío, en el centro-occidente de Colombia, con la participación de 144 estudiantes y 40 docentes, de cuatro Instituciones Educativas públicas. La metodología fue de enfoque cualitativo, donde se empleó como instrumento de recolección y análisis de información, una encuesta tipo cuestionario con preguntas abiertas, para indagar aspectos socioambientales, históricos y paisajísticos del contexto territorial de dicha cuenca. Los resultados develaron que estudiantes y docentes, en general, desconocen los procesos históricos de ocupación humana de la región; con relación a los principales cambios percibidos en el paisaje, los estudiantes señalaron el incremento de las urbanizaciones, la disminución de las zonas verdes y la contaminación, mientras que los docentes manifestaron cambios en los usos del suelo, el crecimiento urbanístico y el desarrollo basado en el turismo. Sin duda, estos hallazgos son importantes, como lectura del territorio, para ser tenidos en cuenta en la praxis de la educación ambiental de las instituciones educativas.

ABSTRACT From the perspective of socio-cultural ecologies as an emerging interdisciplinary field, environmental education can be enriched in an alternative and complementary way since they allow a comprehensive approach to the dynamics of human occupation and transformations in a specific territory from a historical perspective, political and socio-cultural. This research was carried out in the territorial context of the Quindío River basin in central-western Colombia, with the participation of 144 students and 40 teachers from four public educational institutions. The methodology was a qualitative approach, where a questionnaire-type survey with open questions was used as an instrument for collecting and analyzing information to investigate socio-environmental, historical, and landscape aspects of the territorial context of said basin. The results revealed that students and teachers, in general, are unaware of the historical processes of human occupation of the region; Concerning the main changes perceived in the landscape, the students pointed out the increase in urbanizations, the decrease in green areas, and pollution; while teachers expressed changes in land use, urban growth, and development based on tourism. Undoubtedly, these findings are important as a reading of the territory to be considered in the praxis of environmental education in educational institutions.

Building knowledge to save species: 20 years of ichthyological studies in the Tocantins-Araguaia River basin / Construindo conhecimento para salvar espécies: 20 anos de estudos ictiológicos na bacia do rio Tocantins-Araguaia

Abstract: The Tocantins-Araguaia River basin is the largest basin located entirely in the Brazilian territory. The high degree of endemism of its ichthyofauna has been revealed in several studies, with the upper Tocantins River having the largest absolute number of endemic taxa within the Amazon basin. Here we provide an accurate review of the ichthyofauna of the Tocantins-Araguaia River basin, based on collections made between 2000-2020, including an extensive list of valid fish species occurring in the basin and a discussion of the major threats to its ichthyofauna. Ichthyofauna diversity was further refined based on web searches. Protected Areas and hydropower plants were mapped using shape files or coordinates from the responsible government agencies. 751 species of fishes are currently known from the Tocantins-Araguaia River basin. A considerable increase in fish diversity knowledge occurred in the last 20 years, in parallel with significant anthropic alterations in the basin and its surroundings. Dams constructed along the basin are ranked as the major threats to ichthyofauna. Although the drainage-basin holds several conservation units and indigenous lands, they have not been sufficient to guarantee the preservation of fish species. Our compilation emphasizes that the upper Tocantins River must be considered as a priority area to preserve fish species. Some mitigation actions that may achieve satisfactory results concerning ichthyofauna conservation are proposed.

Resumo: A bacia do rio Tocantins-Araguaia é a maior bacia localizada completamente no território brasileiro. O elevado nível de endemismo de sua ictiofauna foi atestado em vários estudos, com o alto rio Tocantins possuindo o maior número absoluto de táxons endêmicos da bacia Amazônica. Aqui, fornecemos uma acurada revisão sobre o conhecimento da ictiofauna da bacia do rio Tocantins-Araguaia entre 2000-2020; uma extensa lista das espécies válidas de peixes ocorrentes na bacia, assim como uma discussão sobre as maiores ameaças para sua ictiofauna. Dados sobre a diversidade da ictiofauna foram refinados por meio de buscas na internet. O mapeamento das Áreas Protegidas e das hidrelétricas foi realizado utilizando os arquivos de área ou coordenadas fornecidas pelas agências governamentais responsáveis. 751 espécies de peixes são atualmente conhecidas para a bacia do rio Tocantins-Araguaia. Um aumento considerável no conhecimento sobre a diversidade de peixes ocorreu nos últimos 20 anos em paralelo com significativas alterações antrópicas na bacia e seu entorno. As represas ao longo da bacia são consideradas a maior ameaça à ictiofauna. Embora a região hidrográfica abrigue diversas unidades de conservação e terras indígenas, estas não têm sido suficientes para garantir a preservação das espécies de peixes. Nossa compilação enfatiza que o alto rio Tocantins precisa ser considerado como área prioritária para a conservação das espécies de peixes. Algumas ações mitigatórias, que podem atingir resultados satisfatórios em relação à conservação da ictiofauna, são também propostas.

Community structure of benthic invertebrates in the Allipén River basin, North Patagonia, Araucania region (38º S, Chile) / Estrutura da comunidade de invertebrados bentônicos na bacia do rio Allipén, Patagônia Norte, Região da Araucanía (38º S, Chile)

One of the biological indicators most used to determine the health of a fluvial ecosystem are the benthic macroinvertebrates. The presence of recurrent species in a wide gradient of latitudes, dominates the biogeographic pattern of the benthic macroinvertebrates in Chilean fresh waters, nevertheless the knowledge on the communitarian ecology of these in the Chilean rivers continues to be scarce. Null models became a powerful statistical tool for describing the ecological mechanisms that drive the structure of an ecological community and the underlying patterns of diversity. The objective of this study was to determine the community structure of benthic invertebrates in the Allipén River by describing their composition, richness and abundance of species through richness models and null models based on presence/absence. The results reveal a high family richness and low diversity, three phyla, five classes, 11 orders and 28 families were identified in the study area during the four seasons of the year. The Arthropoda phylum was the most representative in abundance and richness. Regarding to richness, Trichoptera (7 families) and Diptera (6 families) followed by Ephemeroptera (3 families) were the orders that showed the greatest diversity of families, however, a low diversity with a H'≤ 1.5 nit was registered in the study area. We demonstrated through the null models, the randomization in the species associations corresponding to the three analyzed sites. The information provided here contributes to the understanding of the ecological patterns of the invertebrate communities in the Allipén River, establishing the basis for more complex ecological studies.

Um dos indicadores biológicos mais utilizados para determinar a saúde de um ecossistema fluvial são os macroinvertebrados bentônicos. A presença de espécies recorrentes em um amplo gradiente de latitudes domina o padrão biogeográfico dos macroinvertebrados bentônicos nas águas doces do Chile; no entanto, o conhecimento sobre a ecologia comunitária destes nos rios chilenos continua escasso. Os modelos nulos se tornaram uma poderosa ferramenta estatística para descrever os mecanismos ecológicos que orientam a estrutura de uma comunidade ecológica e os padrões subjacentes da diversidade. O objetivo deste estudo foi determinar a estrutura da comunidade de invertebrados bentônicos no rio Allipén, descrevendo sua composição, riqueza e abundância de espécies através de modelos de riqueza e modelos nulos baseados na presença / ausência. Os resultados revelam alta riqueza de espécies e baixa diversidade, sendo identificados três filos, cinco classes, 11 ordens e 28 famílias na área de estudo durante as quatro estações do ano. O filo de Arthropoda foi o mais representativo em abundância e riqueza. Em relação à riqueza, Trichoptera (7) e Diptera (6) seguidos por Ephemeroptera (3) foram as ordens que mostraram a maior diversidade de famílias, no entanto, uma baixa diversidade com H'≤ 1,5 nit foi registrada na área de estudo. Demonstramos através dos modelos nulos, a randomização nas associações de espécies correspondentes aos três locais analisados. As informações aqui fornecidas contribuem para a compreensão dos padrões ecológicos das comunidades de invertebrados no rio Allipén, estabelecendo a base para estudos ecológicos mais complexos.

Community structure of benthic invertebrates in the Allipén River basin, North Patagonia, Araucania region (38º S, Chile) / Estrutura da comunidade de invertebrados bentônicos na bacia do rio Allipén, Patagônia Norte, Região da Araucanía (38º S, Chile)

One of the biological indicators most used to determine the health of a fluvial ecosystem are the benthic macroinvertebrates. The presence of recurrent species in a wide gradient of latitudes, dominates the biogeographic pattern of the benthic macroinvertebrates in Chilean fresh waters, nevertheless the knowledge on the communitarian ecology of these in the Chilean rivers continues to be scarce. Null models became a powerful statistical tool for describing the ecological mechanisms that drive the structure of an ecological community and the underlying patterns of diversity. The objective of this study was to determine the community structure of benthic invertebrates in the Allipén River by describing their composition, richness and abundance of species through richness models and null models based on presence/absence. The results reveal a high family richness and low diversity, three phyla, five classes, 11 orders and 28 families were identified in the study area during the four seasons of the year. The Arthropoda phylum was the most representative in abundance and richness. Regarding to richness, Trichoptera (7 families) and Diptera (6 families) followed by Ephemeroptera (3 families) were the orders that showed the greatest diversity of families, however, a low diversity with a H'≤ 1.5 nit was registered in the study area. We demonstrated through the null models, the randomization in the species associations corresponding to the three analyzed sites. The information provided here contributes to the understanding of the ecological patterns of the invertebrate communities in the Allipén River, establishing the basis for more complex ecological studies.

Um dos indicadores biológicos mais utilizados para determinar a saúde de um ecossistema fluvial são os macroinvertebrados bentônicos. A presença de espécies recorrentes em um amplo gradiente de latitudes domina o padrão biogeográfico dos macroinvertebrados bentônicos nas águas doces do Chile; no entanto, o conhecimento sobre a ecologia comunitária destes nos rios chilenos continua escasso. Os modelos nulos se tornaram uma poderosa ferramenta estatística para descrever os mecanismos ecológicos que orientam a estrutura de uma comunidade ecológica e os padrões subjacentes da diversidade. O objetivo deste estudo foi determinar a estrutura da comunidade de invertebrados bentônicos no rio Allipén, descrevendo sua composição, riqueza e abundância de espécies através de modelos de riqueza e modelos nulos baseados na presença / ausência. Os resultados revelam alta riqueza de espécies e baixa diversidade, sendo identificados três filos, cinco classes, 11 ordens e 28 famílias na área de estudo durante as quatro estações do ano. O filo de Arthropoda foi o mais representativo em abundância e riqueza. Em relação à riqueza, Trichoptera (7) e Diptera (6) seguidos por Ephemeroptera (3) foram as ordens que mostraram a maior diversidade de famílias, no entanto, uma baixa diversidade com H'≤ 1,5 nit foi registrada na área de estudo. Demonstramos através dos modelos nulos, a randomização nas associações de espécies correspondentes aos três locais analisados. As informações aqui fornecidas contribuem para a compreensão dos padrões ecológicos das comunidades de invertebrados no rio Allipén, estabelecendo a base para estudos ecológicos mais complexos.

Community structure of benthic invertebrates in the Allipén River basin, North Patagonia, Araucania region (38º S, Chile)

Abstract One of the biological indicators most used to determine the health of a fluvial ecosystem are the benthic macroinvertebrates. The presence of recurrent species in a wide gradient of latitudes, dominates the biogeographic pattern of the benthic macroinvertebrates in Chilean fresh waters, nevertheless the knowledge on the communitarian ecology of these in the Chilean rivers continues to be scarce. Null models became a powerful statistical tool for describing the ecological mechanisms that drive the structure of an ecological community and the underlying patterns of diversity. The objective of this study was to determine the community structure of benthic invertebrates in the Allipén River by describing their composition, richness and abundance of species through richness models and null models based on presence/absence. The results reveal a high family richness and low diversity, three phyla, five classes, 11 orders and 28 families were identified in the study area during the four seasons of the year. The Arthropoda phylum was the most representative in abundance and richness. Regarding to richness, Trichoptera (7 families) and Diptera (6 families) followed by Ephemeroptera (3 families) were the orders that showed the greatest diversity of families, however, a low diversity with a H 1.5 nit was registered in the study area. We demonstrated through the null models, the randomization in the species associations corresponding to the three analyzed sites. The information provided here contributes to the understanding of the ecological patterns of the invertebrate communities in the Allipén River, establishing the basis for more complex ecological studies.

Resumo Um dos indicadores biológicos mais utilizados para determinar a saúde de um ecossistema fluvial são os macroinvertebrados bentônicos. A presença de espécies recorrentes em um amplo gradiente de latitudes domina o padrão biogeográfico dos macroinvertebrados bentônicos nas águas doces do Chile; no entanto, o conhecimento sobre a ecologia comunitária destes nos rios chilenos continua escasso. Os modelos nulos se tornaram uma poderosa ferramenta estatística para descrever os mecanismos ecológicos que orientam a estrutura de uma comunidade ecológica e os padrões subjacentes da diversidade. O objetivo deste estudo foi determinar a estrutura da comunidade de invertebrados bentônicos no rio Allipén, descrevendo sua composição, riqueza e abundância de espécies através de modelos de riqueza e modelos nulos baseados na presença / ausência. Os resultados revelam alta riqueza de espécies e baixa diversidade, sendo identificados três filos, cinco classes, 11 ordens e 28 famílias na área de estudo durante as quatro estações do ano. O filo de Arthropoda foi o mais representativo em abundância e riqueza. Em relação à riqueza, Trichoptera (7) e Diptera (6) seguidos por Ephemeroptera (3) foram as ordens que mostraram a maior diversidade de famílias, no entanto, uma baixa diversidade com H 1,5 nit foi registrada na área de estudo. Demonstramos através dos modelos nulos, a randomização nas associações de espécies correspondentes aos três locais analisados. As informações aqui fornecidas contribuem para a compreensão dos padrões ecológicos das comunidades de invertebrados no rio Allipén, estabelecendo a base para estudos ecológicos mais complexos.

Population structuration and chromosomal features homogeneity in Parodon nasus (Characiformes: Parodontidae): A comparison between Lower and Upper Paraná River representatives

The ichthyofauna of the La Plata hydrographic basin is divided into Upper and Lower Paraná River systems due to the geographic isolation of the Sete Quedas waterfalls, currently flooded by the lake of the Itaipu dam. In Parodontidae, pairs of species, or groups of cryptic species were described between these systems. Although genetic isolation and speciation have already been proposed in other species in the group, Parodon nasus has been maintained as a valid species and distributed throughout the La Plata river basin. In this perspective, specimens of P. nasus from four different sampling sites in the Upper and Lower Paraná River systems were compared regarding the karyotypes, molecular analyzes of population biology and species delimitation to investigate their genetic and population isolation in the La Plata river basin. Despite a geographic barrier and the immense geographic distance separating the specimens sampled from the Lower Paraná River system compared to those from the Upper Paraná River, the data obtained showed P. nasus as a unique taxon. Thus, unlike other species of Parodontidae that showed diversification when comparing the groups residing in the Lower versus Upper Paraná River, P. nasus showed a population structure and a karyotypic homogeneity.(AU)

A ictiofauna do sistema hidrográfico La Plata é dividida em alto e baixo rio Paraná devido ao isolamento geográfico dos Saltos das Sete Quedas há 22 milhões de anos, atualmente inundado pelo lago da represa da Usina de Itaipu. Em Parodontidae, espécies pares ou grupos de espécies crípticas foram descritos entre esses sistemas. Contudo, embora o isolamento genético e especiação já tenham sido propostos em outras espécies do grupo, Parodon nasus tem sido mantido como espécie válida e distribuída em toda a bacia do rio La Plata. Nessa perspectiva, exemplares de P. nasus de quatro diferentes pontos de amostragem nos sistemas do alto e baixo rio Paraná foram comparados quanto ao arranjo dos cariótipos, análises moleculares de biologia populacional e delimitação de espécies, afim de investigar seu isolamento genético e populacional na bacia do rio La Plata. Apesar da barreira geográfica e imensa distância geográfica separando os exemplares amostrados no sistema baixo rio Paraná em comparação àqueles do alto rio Paraná, os dados obtidos demonstraram P. nasus como único táxon válido. Dessa forma, diferentemente de outras espécies de Parodontidae que demonstraram diversificação quando comparados grupos pares residentes no baixo e alto rio Paraná, P. nasus demonstrou estruturação populacional e homogeneidade cariotípica.(AU)

Flood pulse influence on the feeding ecology of two Amazonian auchenipterid catfishes

We assessed the flood pulse effect on the diet composition, trophic niche breadth, and the amount of food intake of two Amazonian auchenipterids with different feeding strategies. Sampling was carried out quarterly (from April/2012 to January/2014) on the middle Xingu River, using gillnets. We measured specimens for standard length and total weight. The specimens' stomachs were removed, weighed, and had their contents identified. We analyzed 360 stomachs of Auchenipterus nuchalis and 584 of Tocantinsia piresi. The diet of A. nuchalis was mainly composed of aquatic insects and crustaceans, while T. piresi fed on fruits and seeds. The diet composition of both species varied seasonally, but only T. piresi changed its trophic niche breadth in response to hydrological changes, becoming more specialist during the higher water periods (filling and flood). Both species also showed differences in their amount of food intake between hydrological periods, with A. nuchalis feeding more intensely in lower water periods (ebb and dry), while T. piresi in the higher water periods. We evidenced different responses to the hydrological periods for the related species. We emphasize that studies considering the relationship between flood pulse and feeding ecology of the organisms are essential to understanding river floodplain systems' dynamics.(AU)

Avaliamos o efeito do pulso de inundação na composição da dieta, amplitude de nicho trófico e quantidade de alimento ingerido de dois auchenipterídeos amazônicos com diferentes estratégias alimentares. Os espécimes foram amostrados trimestralmente entre abril/2012 e janeiro/2014 no médio rio Xingu, utilizando malhadeiras. Estes foram mensurados quanto ao comprimento padrão e peso total. Os estômagos dos espécimes foram removidos, pesados e seu conteúdo identificado. Analisamos 360 estômagos de Auchenipterus nuchalis e 584 de Tocantinsia piresi. A dieta de A. nuchalis foi predominantemente composta por insetos aquáticos e crustáceos, enquanto para T. piresi frutos e sementes predominaram. A composição da dieta de ambas as espécies variou sazonalmente, mas apenas para T. piresi a amplitude de nicho trófico variou entre períodos hidrológicos, sendo mais especialista nos períodos de águas altas (enchente e cheia). Ambas as espécies diferiram na quantidade de alimento ingerido entre os períodos hidrológicos, sendo maior para A. nuchalis nos períodos de águas baixas (vazante e seca) e para T. piresi nos períodos de águas altas. Evidenciamos diferentes respostas à variação hidrológica pelas espécies. Enfatizamos que estudos considerando a relação entre a dinâmica do pulso de inundação e a ecologia alimentar dos organismos é fundamental para um melhor entendimento da dinâmica das planícies de inundação.(AU)

Fishes of the Mitú Region: middle basin of the río Vaupés, Colombian Amazon / Peces de la región de Mitú: cuenca media del río Vaupés, Amazonia colombiana

Abstract: The Amazon River basin hosts the most diverse freshwater ichthyofauna in the world, and yet huge areas of the basin remain unexplored. This is the case for the upper tributaries of the rio Negro, especially those draining the Colombian territory. Here we present a list of 224 species derived from the examination of specimens collected in the Mitú region (Vaupés Department, Colombia), the middle basin of the río Vaupés. Of the species identified in our study, 10 species are recorded from Colombia for the first time, and 26 species are newly recorded from the Colombian Amazon. The number of species we present here comprise almost one-third of the known species diversity of the Colombian Amazon and nearly a tenth of the total number of those known across the entirety of the Amazon basin. The most diverse orders were Characiformes (120 species) and Siluriformes (65 species), and the remaining six orders comprised less than 20% of total species. The study area comprised blackwater systems, which are considered to be nutrient-poor environments. We discuss some ecological aspects that might explain how this highly diverse ichthyofauna originates and is maintain in less productive systems. The list presented here adds an important number of new records and complements the information derived from previous studies, carried out thus far with regards to the fish fauna of the Colombian Amazon.

Resumo: La cuenca del río Amazonas alberga la ictiofauna dulceacuícola más diversa del mundo, sin embargo, grandes áreas de la cuenca permanecen inexploradas. Este es el caso de los afluentes de la parte alta del río Negro, especialmente los sistemas que drenan el territorio colombiano. A continuación, presentamos un listado de 224 especies derivadas del análisis de especímenes recolectados en la región de Mitú, cuenca media del río Vaupés (Departamento de Vaupés, Colombia). De las especies identificadas, 10 especies se registran en Colombia por primera vez y 26 especies para la Amazonía colombiana. El número de especies que presentamos aquí comprende casi un tercio de las especies conocidas para la Amazonía colombiana y casi una décima parte del total de las conocidas para la gran cuenca del Amazonas. Los órdenes más diversos fueron Characiformes (120 especies) y Siluriformes (65 especies), y los seis órdenes restantes comprendieron menos del 20% del total de especies. El área de estudio comprende sistemas de aguas negras que se consideran ambientes poco productivos por sus bajos contenidos de nutrientes. Discutimos aquí algunos aspectos ecológicos que podrían explicar cómo esta ictiofauna tan diversa tiene su origen y es mantenida en estos sistemas poco productivos. La información derivada del presente estudio adiciona nuevos registros de especies de peces para Colombia, y complementa la información derivada de los estudios realizados a la fecha en la Amazonía colombiana.

Checklist of freshwater fishes from Loreto, Peru / Lista de especies de peces de agua dulce de Loreto, Perú

Abstract This study presents an extensive review of published and unpublished occurrence records of fish species in the Loreto department. Located in the northeast of the country, Loreto is the most geographically extensive region in the Peruvian territory. Despite the increase in fish collections in Loreto in recent years, the ichthyofauna of this department needs to be more documented. Based on a database of scientific collections and bibliographic information, an updated checklist of the freshwater fishes from Loreto is presented. The results reveal a rich and diversified ichthyofauna, with 873 species distributed in 331 genera, 50 families and 15 orders. The main groups are Characiformes (42.6%), Siluriformes (34.8%), Gymnotiformes (8.6%) and Cichliformes (7.4%). Part of the ichthyofauna has restricted distribution for Loreto (4.7%). In addition, 9.0% of species from Loreto are used in fisheries. Meanwhile, 219 species (25%) were categorized according to the IUCN criteria where only six species (0.7%) are currently considered threatened species (CR, EN or VU). The results presented in this work indicate that this department needs more studies to know the biodiversity of fish, likewise, the information presented constitutes a contribution to the knowledge of fish diversity that would support environmental management actions and decision-making aimed at conserving one of the most diverse departments of Peru.

Resumen Este trabajo presenta una revisión de los registros de especies de peces, publicados y no publicados, del departamento de Loreto. Localizado al noreste del país, Loreto es el departamento más extenso del territorio peruano. A pesar del incremento en el número de las colectas de peces en Loreto en años recientes, la ictiofauna de este departamento necesita ser más documentada. Sustentado en los registros en bases de datos de colecciones científicas e información bibliográfica, se presenta una actualización de la lista de peces de agua dulce de Loreto. Los resultados revelaron una ictiofauna rica y diversificada, con 873 especies, distribuidas en 331 géneros, 50 familias y 15 órdenes. Los principales taxones fueron Characiformes (42.6%), Siluriformes (34.8%), Gymnotiformes (8.6%) y Cichliformes (7.4%). Parte de la ictiofauna tiene distribución restricta para Loreto (4.7%). Además, 9.0% de las especies son usadas en pesquerías de Loreto. Mientras tanto, 219 (25%) especies fueron categorizadas de acuerdo con los criterios de la IUCN, donde sólo seis especies (0.7%) son consideradas actualmente especies amenazadas (CR, EN o VU). Los resultados presentados en este trabajo señalan que este departamento necesita más estudios para conocer la biodiversidad de peces, así mismo, la información presentada constituye un aporte al conocimiento de la biodiversidad íctica que respaldarían las acciones de gestión ambiental y toma de decisiones destinados a conservar uno de los departamentos más diversos del Perú.

Putative poison gland in the thorny catfish Acanthodoras spinosissimus (Siluriformes: Doradidae) / Suposta glândula de veneno no bagre rebeca Acanthodoras spinosissimus (Siluriformes: Doradidae)

Acanthodoras is the only genus of catfish known to secrete a conspicuous and abundant milky-looking substance through an axillary pore located just below the base of the posterior cleithral process. Despite this remarkable feature, there is no published information on the anatomical structures that produce the secretion and its possible biological/ecological functions. Dissection and histological analysis of preserved specimens of A. spinosissimus revealed the presence of a saccular axillary gland with large, binuclear secretory cells, similar to those found in other poisonous catfish. Secretory cells near the lumen appear to lose nuclei and become filled with secretory products, possibly with proteinaceous elements, as indicated by their eosinophilic appearance. As far as we know, the saccular morphology of the gland appears to constitute a unique characteristic of Acanthodoras among Doradidae catfishes. Further studies are necessary to determine the chemical composition of the secretion, as well as its possible uses by the catfish in its natural environment.

Acanthodoras é o único gênero de bagre conhecido por secretar uma substância de aparência leitosa conspícua e abundante através de um poro axilar localizado logo abaixo da base do processo cleitral posterior. Apesar dessa característica marcante, não há informações publicadas sobre as estruturas anatômicas que produzem a secreção, nem sobre suas possíveis funções biológicas/ecológicas. A dissecção e análise histológica de espécimes preservados de A. spinosissimus revelaram a presença de uma glândula axilar sacular com células secretoras binucleares, semelhantes às encontradas em outros bagres venenosos. As células secretoras próximas ao lúmen parecem perder os núcleos e são preenchidas com produtos secretores, possivelmente com elementos proteicos, conforme indicado por sua aparência eosinofílica. Até onde sabemos, a morfologia sacular da glândula parece constituir uma característica única de Acanthodoras entre os bagres Doradidae. Mais estudos são necessários para determinar a composição química da secreção, bem como seus possíveis usos pelo bagre em seu ambiente natural.

Putative poison gland in the thorny catfish Acanthodoras spinosissimus (Siluriformes: Doradidae)

ABSTRACT Acanthodoras is the only genus of catfish known to secrete a conspicuous and abundant milky-looking substance through an axillary pore located just below the base of the posterior cleithral process. Despite this remarkable feature, there is no published information on the anatomical structures that produce the secretion and its possible biological/ecological functions. Dissection and histological analysis of preserved specimens of A. spinosissimus revealed the presence of a saccular axillary gland with large, binuclear secretory cells, similar to those found in other poisonous catfish. Secretory cells near the lumen appear to lose nuclei and become filled with secretory products, possibly with proteinaceous elements, as indicated by their eosinophilic appearance. As far as we know, the saccular morphology of the gland appears to constitute a unique characteristic of Acanthodoras among Doradidae catfishes. Further studies are necessary to determine the chemical composition of the secretion, as well as its possible uses by the catfish in its natural environment.

RESUMO Acanthodoras é o único gênero de bagre conhecido por secretar uma substância de aparência leitosa conspícua e abundante através de um poro axilar localizado logo abaixo da base do processo cleitral posterior. Apesar dessa característica marcante, não há informações publicadas sobre as estruturas anatômicas que produzem a secreção, nem sobre suas possíveis funções biológicas/ecológicas. A dissecção e análise histológica de espécimes preservados de A. spinosissimus revelaram a presença de uma glândula axilar sacular com células secretoras binucleares, semelhantes às encontradas em outros bagres venenosos. As células secretoras próximas ao lúmen parecem perder os núcleos e são preenchidas com produtos secretores, possivelmente com elementos proteicos, conforme indicado por sua aparência eosinofílica. Até onde sabemos, a morfologia sacular da glândula parece constituir uma característica única de Acanthodoras entre os bagres Doradidae. Mais estudos são necessários para determinar a composição química da secreção, bem como seus possíveis usos pelo bagre em seu ambiente natural.

A fjord-like tropical ecosystem, Pacific coast of Costa Rica: overview of research in Golfo Dulce / Un ecosistema tropical similar a un fiordo, costa del Pacífico de Costa Rica: panorama de la investigación en el Golfo Dulce

Abstract Introduction: Coastal ecosystems worldwide are under the influence of local, regional and global stressors, such as pollution, eutrophication and climate change. Golfo Dulce is a relatively pristine and accessible deep tropical ecosystem that provides opportunities for comparative and collaborative research. Objective: To summarize published reports on past research conducted in this ecosystem, identify topics for further study, and suggest new research issues. Methods: A search was made on the web for reports based on research conducted in Golfo Dulce and published in scientific journals. Reports focusing on environmental parameters and on the biota were included. Results: A total of 123 studies that include data from Golfo Dulce are cited. The four topics more frequently addressed were reports based on the results of the R/V Victor Hensen expedition (1993-1994) and follow-up work on microbiology, studies on water parameters, research on vertebrates, and zooplankton studies. The reports focusing on vertical profiles of oxygen and temperature are discussed in detail, followed by those on the biota. Conclusions: Golfo Dulce has low oxygen concentrations below 50 m and is frequently anoxic at the 200 m deep basin with occasional formation of H2S. However, the ecosystem contains a relatively high diversity of identified organisms, from bacteria to whales. Of particular relevance for future studies are multidisciplinary surveys aiming at obtaining data on primary productivity, the diversity and biomass of the main groups of planktonic, demersal and benthic organisms, and the frequency and magnitude of the influx of deep offshore waters over the sill into the basin. These data, as well as the information gathered in the past, are essential for updating the trophic model developed more than 25 years ago and in support of new predictive models on the functioning of the ecosystem.

Resumen Introducción: Los ecosistemas costeros alrededor del mundo están bajo la influencia de tensores locales, regionales y globales, como la contaminación, la eutroficación y el cambio climático. El Golfo Dulce es un profundo ecosistema tropical relativamente inalterado y accesible, que provee oportunidades para la investigación comparativa y colaborativa. Objetivo: Resumir los informes publicados sobre investigaciones pasadas realizadas en el ecosistema, identificar tópicos para estudios futuros y sugerir nuevas áreas de investigación. Métodos: Se hizo una búsqueda en la red de informes basados en investigaciones hechas en Golfo Dulce y publicadas en revistas científicas. Fueron incluidos aquellos informes sobre parámetros ambientales y la biota. Resultados: Un total de 123 estudios que incluyen datos sobre Golfo Dulce son citados. Los cuatro tópicos citados con más frecuencia fueron: Los resultados de la expedición del R/V Victor Hensen (1993-1994) y estudios de seguimiento sobre microbiología, informes sobre parámetros acuáticos, investigaciones sobre vertebrados y estudios sobre zooplancton. Los informes sobre perfiles de oxígeno y temperatura son presentados con mayor detalle, seguidos por aquellos sobre la biota. Conclusiones: Golfo Dulce tiene bajas concentraciones de oxígeno por debajo de 50 m y es usualmente anóxico a 200 m en el fondo, con formación ocasional de H2S. Sin embargo, el ecosistema contiene una diversidad de organismos identificados relativamente alta, desde bacterias hasta ballenas. De relevancia particular para futuros estudios es, entre otros, la conducción, de muestreos multidisciplinarios orientados a obtener datos sobre productividad primaria, la diversidad y biomasa de los principales grupos de organismos planctónicos, demersales y bénticos, así como la frecuencia y magnitud del flujo de agua oceánica hacia el interior. Estos datos, así como los obtenidos en el pasado, son esenciales para actualizar el modelo trófico desarrollado hace más de 25 años, o en apoyo de nuevos modelos predictivos de funcionamiento del ecosistema.

An investigation on systematic history and distribution areas of tarek (Alburnus tarichi (Güldenstädt, 1814)) / Uma investigação sobre a história sistemática e as áreas de distribuição de tarek (Alburnus tarichi (Güldenstädt, 1814))

Abstract This study aimed to determine the distribution area of tarek (Alburnus tarichi (Güldenstädt, 1814)) and to define how it must be called according to the scientific name by evaluating its previous studies made by various systematisers and their reports on its distribution, and by comparing literature knowledge. The taxonomic characteristics of the collected samples were evaluated and several measurements and counts were taken on the samples; analfin origin 0-4 scales behind dorsal fin-base; 72-91 lateral line scales; 21-29 gill rakers; 7½-10 branched dorsal-fin rays and 10-12½ branched anal-fin rays. Body and caudal peduncle was moderately compressed. Body was covered by overlapping scales. Tarek has five different populations in the Basin. They are Van, Erçek, Nazik and Aygır Lakes and Koçköprü Dam Lake populations. The main living area of the tarek population is Lake Van; however, between May and June, mature individuals of tarek enter to tributaries of Van Lake. Some of them are Karasu, Bendimahi, Deliçay, Zilan, Karmuç, Sapur, Yanıkçay, Gevaş, Engil, Kurubaş and Akköprü Streams. At the end of study, it was concluded that tarek should be called as Alburnus tarichi (Güldenstädt, 1814) and it is an endemic fish species distributed only in Van Lake Basin.

Resumo Este estudo teve como objetivo determinar a área de distribuição de tarek (Alburnus tarichi) (Güldenstädt, 1814) e definir como deve ser chamado de acordo com o nome científico, avaliando estudos anteriores feitos por vários sistematizadores e seus relatórios sobre sua distribuição, e comparando o conhecimento da literatura. As características taxonômicas das amostras coletadas foram avaliadas e várias medições e contagens foram realizadas nas amostras, como origem analfin 0-4 escalas atrás da base da barbatana dorsal; 72-91 escalas de linha lateral; 21-29 rakers branquiais; 7½-10 raios da nadadeira dorsal ramificada, e 10-12½ raios da nadadeira anal ramificados. Pedúnculo caudal e corporal foram moderadamente comprimidos. O corpo estava coberto por escamas sobrepostas. Tarek tem cinco populações diferentes na bacia estudada. São as populações dos lagos Van, Erçek, Nazik e Aygır, e Koçköprü barragem. A principal área de presença da população tarek é o Lago Van; no entanto, entre maio e junho, indivíduos maduros de tarek entram nos afluentes do lago Van. Alguns deles são os fluxos Karasu, Bendimahi, Deliçay, Zilan, Karmuç, Sapur, Yanıkçay, Gevaş, Engil, Kurubaş e Akköprü. No final do estudo, concluiu-se que tarek deveria ser chamado Alburnus tarichi (Güldenstädt, 1814) e que é uma espécie de peixe endêmica distribuída apenas na Bacia do Lago Van.