Poverty-Food Insecurity Nexus in the Post-Construction Context of a Large Hydropower Dam in the Brazilian Amazon.

Within the 2030 Sustainable Development Agenda, large hydropower dams are positioned as a sustainable energy source, notwithstanding their adverse impacts on societies and ecosystems. This study contributed to ongoing discussions about the persistence of critical social issues, even after the investments of large amounts of resources in areas impacted by the construction of large hydropower dams. Our study focused on food insecurity and evaluated this issue in the city of Altamira in the Brazilian Amazon, which has been profoundly socially and economically impacted by the construction, between 2011 and 2015, of Brazil's second-largest dam, namely, Belo Monte. A survey in Altamira city featured a 500-household random sample. Structural equation modeling showed conditioning factors of 60% of the population experiencing varying food insecurity degrees. Poverty, female-led households, lower education, youth, and unemployment were strongly linked to higher food insecurity. Crowded, officially impacted, and resettled households also faced heightened food insecurity. Our findings underscore the food insecurity conditions in the region impacted by the Belo Monte dam, emphasizing the need to take into account this crucial issue while planning and implementing hydropower dams.

Fish community turnover in a dammed Andean River over time

We describe the change in the fish community of the Porce River in Magdalena River Basin, Colombia, following the construction of the Porce III hydropower reservoir based on 13 years of monitoring data. The results show a clear reduction of the number of native species, which have been supplanted by colonizing non-native species, especially in the reservoir. Four native species detected prior to dam construction have apparently disappeared, but 12 new species were registered post-construction. We analyzed spatial changes in beta diversity in the aquatic environments surrounding the dam. The new environment generated by the reservoir presents a unique species composition and contributes significantly to the total beta diversity of the system. Altogether three distinct new fish assemblages emerged following reservoir formation and there are now six assemblages where there had previously been three. This dramatic change, already visible within a decade of construction, highlights just how strong of an impact dam construction has on habitats and how rapidly fish communities react in this hotspot for endemic fish diversity. Our findings demonstrate the importance of monitoring fish communities for revealing the impact of damming on river ecosystems and informs potential complementary fish diversity inventories elsewhere in the Magdalena River basin.(AU)

Describimos el cambio en la comunidad de peces del río Porce en la cuenca del río Magdalena en Colombia luego de la construcción del embalse hidroeléctrico Porce III con base en 13 años de datos de monitoreo. Los resultados mostraron una reducción de especies nativas y, el embalse ha sido colonizado por especies no nativas. A lo largo del monitoreo cuatro especies desaparecieron de las capturas, y se registró la aparición de 12 especies nuevas después de la construcción del embalse. Analizamos los cambios espaciales en la diversidad beta en los ambientes acuáticos que rodean la presa. El nuevo entorno generado por el embalse presenta una composición de especies única; en total, surgieron tres nuevos ensamblajes de peces distintos después de la formación del embalse y ahora hay seis ensamblajes. Este cambio, ya visible a una década de la construcción, resalta cuán fuerte es el impacto que tiene la construcción de presas en los hábitats y cuán rápido reaccionan las comunidades de peces. Nuestros hallazgos demuestran la importancia de monitorear las comunidades de peces para revelar el impacto de las represas en los ecosistemas fluviales, además permite complementar los inventarios de diversidad en la cuenca del río Magdalena.(AU)

Tracing institutional surprises in the water-energy nexus: Stalled projects of Chile's small hydropower boom.

In this paper, we examine small hydropower trends in Chile through institutional and ethnographic research and we reflect on what lessons this case provides for scholarship on the water-energy nexus. Contrary to the tendency in water-energy nexus scholarship to advocate for further integration of water and energy management, this paper explains an approach to investigation that answers recent calls to politicize the nexus by examining inequity and inefficiency. Methodologically, we trace institutional surprises in water-energy nexus interactions. Internationally, small hydropower growth is part of a boom in renewable energy, yet in Chile the reality is more complicated. We examine the paradoxical trend of hundreds of stalled small hydropower projects that remain incomplete throughout central to southern Chile. These stalled projects indicate unexpected behavior in how water, energy, and environmental institutions interact, in Mapuche Indigenous territory specifically where projects are highly conflictive. A fantastical materialism is also visible. Government and private sector ambitions of organized, massive, and lucrative small hydropower development are resulting in unruly material realities, yet over time capital finds an unforeseen way to produce value. In this case, water rights are being sold with approved environmental impact studies on the water market. Overall, our findings challenge the assumptions that commodifying water can be done equitably and efficiently for all parties involved, in particular for the Mapuche people. Findings also question hydropower's future viability as a sustainable renewable energy endeavor in a market-driven system.

Interplay of geomorphology and hydrology drives macroinvertebrate assemblage responses to hydropeaking.

Hydropeaking leads to major anthropogenic disturbance of river networks worldwide. Flow variations imposed by hydropeaking may significantly affect macroinvertebrate assemblages within the river network. As such, the responses of macroinvertebrate assemblages to hydropeaking are expected to be complex and vary across spatial and temporal scales as well as ecological organization levels. To unpack this complexity, we assessed the interplay of geomorphic and hydrological variables as drivers of the responses of macroinvertebrate assemblages to hydropeaking. Specifically, we studied different levels of ecological organization of macroinvertebrate assemblages in two functional process zones (FPZs; Sub-Andean and Central Valley Gravel Dominated) subjected to different flow management in two Chilean Andean river networks. Hydropeaking caused significant reduction of macroinvertebrate abundances in both FPZs and at all ecological organization levels with the exception of one feeding guild (scrapers). Furthermore, the response of macroinvertebrate assemblage variance was stronger in the Central Valley Gravel Dominated FPZ. Both geomorphic and hydrological variables influenced macroinvertebrate assemblage responses. However, the effects of the principal geomorphic variables operated at valley (meso) spatial scale and the main hydrological variables operated at the sub-daily (micro) temporal scale. Therefore, to minimise the effects of hydropeaking on macroinvertebrate assemblages, flow management should consider reduction of sub-daily variability. Furthermore, placement of new barriers should take into account not only their position within the river network but also their effects downstream that strongly depend on characteristics of river valley.

The Downstream Impacts of Hydropower Dams and Indigenous and Local Knowledge: Examples from the Peace-Athabasca, Mekong, and Amazon.

There has been much written about the negative social and environmental impacts of large hydropower dams, particularly the impacts on people and the environment caused by flooding linked to the creation of large reservoirs. There has also long been recognition of the importance of Indigenous and local knowledge for understanding ecological processes and environmental impacts. In this paper, however, we focus on a topic that has received insufficient consideration: the downstream impacts of dams, and the role of Indigenous and local knowledge in assessing and addressing these impacts. Using examples from three river basins in different parts of the world: the Peace-Athabasca in Canada, the Mekong in mainland Southeast Asia, and the Amazon in Brazil, we demonstrate that the downstream impacts of hydropower dams are often neglected due to the frequently long distances between dams and impacted areas, jurisdictional boundaries, and the less obvious nature of downstream impacts. We contend that Indigenous or local knowledge, if applied consistently and appropriately, has important roles to play in understanding and addressing these impacts, with the goal of avoiding, reducing, and appropriately compensating for the types of environmental injustices that are frequently associated with the downstream impacts of dams.

Hydropower development, collective action, and environmental justice in the Brazilian Amazon.

The Brazilian Amazon has long served as a site of infrastructure development and natural resource extraction. Development projects including dams and mines have largely benefitted distant urban actors at a cost to local communities and the environment. We draw from theories of internal colonialism and environmental justice to examine the ways that dam building undermined the well-being of communities affected by construction of the Belo Monte Dam, and to understand how those communities engaged in collective action to minimize negative impacts on their livelihoods. Drawing from semi-structured interview and ethnographic data, we find that farmers and fishers impacted by Belo Monte used a variety of tactics to resist exploitation and ultimately receive more equitable compensation for their losses. We propose two processes were central to their success in mobilizing for environmental justice: transformative resistance and collaborative claims-making.

The monthly dynamics of blue water footprints and electricity generation of four types of hydropower plants in Ecuador.

Water evaporates from reservoirs of hydropower plants (HPPs), often in significant volumes. Reservoir evaporation is a dynamic phenomenon depending on climate, varying size of open water surfaces (OWS), and electricity production. Due to a lack of data and methods to estimate the OWS's size variation, previous studies assessed HPPs water footprints (WFs) considering static OWSs acknowledging the uncertainty of this omission. This study estimates WFs of HPPs, considering dynamic OWSs for four plant types in Ecuador, Flooded lakes, and Flooded rivers, with dam heights lower or higher than their Gross Static Head (GSH). It quantifies OWSs size variation using a Digital Elevation Model and GSH data, assessing OWS evaporation, effects on electricity production and WFs. There are large differences among the evaporation of HPPs when OWS size variations are considered. HPP operation, geographical features, and climate determine temporal differences. Flooded lake HPPs have relatively large WFs. Flooded River HPPs, with dam heights below their GSH, have the smallest WFs, but water storage capacity is limited. Static area approaches underestimated annual WFs by 10% (Flooded Lake HPPs) to 80% (Flooded River HPPs). Earlier studies showed effects of HPPs on water from a water management perspective, suggesting that less water-intensive HPP technologies are favorable, or that other water-efficient electricity-generating technologies, like solar or wind, should replace HPPs. This study also included the electricity perspective, indicating that energy management and water storage are important factors for WFs. The most water-effective technology cannot fulfill current electricity production due to a lack of storage options. The system dynamics analysis indicates that aiming for small WFs is not always the best option from an energy and water perspective.

Biodiversity of Hematophagous Diptera (Culicidae and Psychodidae) in a Small Hydroelectric Power Station and Surrounding Area in the State of Minas Gerais, Brazil.

Hydroelectric power stations may affect the population dynamics of mosquitoes and sand flies, a group with impact on public health due to the possibility to transmit pathogens to humans. This work characterized and compared the fauna of mosquitoes and sand flies in a hydroelectric power station and peridomicile areas in the State of Minas Gerais, Brazil. Insect collections were performed in August 2015 at dry season and February 2016 in rainy season. Ten HP light traps were set at each of two sites for three consecutive days in each of two seasons (dry and rainy). Furthermore, collections with Shannon traps were made in each sampling area (hydropower plant and peridomicile area) from 4:00 p.m. being shut down at 8:00 p.m. for two consecutive days in each of two seasons (dry and rainy). In total, 1,222 insects from 13 genera and 27 species were collected. The most plentiful species were respectively Culex declarator (Dyar and Knab, 1906) and Pintomyia pessoai (Coutinho & Barretto, 1940). A high number of insects (78.5%) were collected during the rainy period (P < 0.05). About equitability, statistical significance was observed in the peridomicile area (dry season J = 0.75 and rainy season J = 0.82). The highest values of species diversity were observed in the hydropower plant (H = 2.68) and peridomicile area (H = 2.38) both in the rainy season with statistical significance comparing with dry season. Our results demonstrate that the occurrence of vector species in this region increases the potential risk of transmission of pathogens, especially arbovirus and Leishmania Ross, 1903.

Dams, Chinese investments, and EIAs: A race to the bottom in South America?

The political economy of dam development in South America is changing as a result of a resurgence in water infrastructure investments. The arrival of Chinese-funded projects in the region has altered a context traditionally dominated by multilateral development banks. Tensions are escalating around new dam projects and the environmental impact assessment process is increasingly the site of politicization around water in the region. In this perspective, we examine the most recent surge in dam development in South America, the resulting environmental and social impacts, and the mobilization of civil society and environmental groups that have developed in response to these projects. In the absence of regionally shared standards for environmental assessment and regional mechanisms to mitigate the emerging conflicts-primarily occurring between companies, states, and civil society-we argue there is a risk of a race to the bottom to finance infrastructure projects with laxer environmental and social standards.

Mercury contamination levels in the bioindicator piscivorous fish Hoplias aïmara in French Guiana rivers: mapping for risk assessment.

In French Guiana, native populations present high level of mercury contamination, which has been linked to the consumption of contaminated fishes. The goal of this study is to undertake a cartography of mercury contamination levels in fishes from the six main Guiana rivers. The selected species for this study is the ubiquitous piscivorous fish Hoplias aimara. A total number of 575 fishes from 134 discrete fishing sites are regrouped into 51 river sectors. Results from this study permits to rank the six main Guiana rivers by their mean level of contamination: Oyapock (0.548 mg kg-1), Comté (0.624 mg kg-1), Maroni (0.671 mg kg-1), Approuague (0.684 mg kg-1), Mana (0.675 mg kg-1), and Sinnamary (1.025 mg kg-1). The contamination is however not spatially homogenous along each river, and a map of the different levels of mercury contamination in fishes is provided. Sectors of low mean Hg contamination are observed both upstream (0.471 mg kg-1) and downstream (0.424 mg kg-1), corresponding to areas without any influence of gold mining activities and areas under the influence of estuarine dilution, respectively. Anoxia and gold mining activities are found to be the two main factors responsible for the high mercury concentration in fish muscles. While mean levels of mercury contaminations are higher in anoxia areas (1.029 mg kg-1), contaminations induced by gold mining activities (0.717 mg kg-1) present the most harmful consequences to human populations. No significant differences in Hg concentrations are observed between 2005 and 2014 for neither a pristine nor a gold mining area, while Hg concentration differences are observed between former (0.550 mg kg-1) and current gold mining sites (0.717 mg kg-1).

The use of dead stand trees by birds: a prospective study in a Brazilian hydroelectric dam / O uso de paliteiros por aves: um estudo prospectivo em uma usina hidrelétrica no Brasil

Abstract: Hydropower constructions cause severe disturbances to biodiversity. Arboreal plants die after flooding; however, they expose their emerged branches (also called paliteiros) as a new habitat for animals and plants. Nothing is known about how paliteiros influence the presence of aquatic birds. This study verified which species of birds use the paliteiros, what are their behaviors and probably consequences to ecological processes. In November 2018, we sampled 5 km of paliteiros recording perched birds and their behaviors in the Três Marias dam, a 1040 km2 flooded area in southeastern Brazil. In total, 5.4% of paliteiros were used by 14 bird species. The Neotropic Cormorant Nannopterum brasilianus (Gmelin, 1789) was the most frequent species. Birds mainly preened feathers; they also rested (with no apparent activity), defecated, hunted, fed, vocalized and drank water. Attention must be focused to some behaviors such as resting and defecation, which may influence long-term ecological processes (e.g., incorporating additional organic matter and changing aquatic community) in the dam.

Resumo: Construções de hidrelétricas causam severos distúrbios à biodiversidade. Após a inundação de grandes áreas as plantas arbóreas morrem, apesar disso, elas deixam expostos seus galhos emersos (também chamados de paliteiros) criando um novo hábitat para animais e plantas. Nada se sabe sobre como os paliteiros influenciam a presença de aves aquáticas. Este estudo verificou quais espécies de aves utilizam os paliteiros, quais comportamentos elas exibem e suas prováveis consequências para processos ecológicos. Em novembro de 2018 foram amostrados 5 km de paliteiros, as aves empoleiradas nestas estruturas e seus comportamentos na represa de Três Marias, uma área inundada de 1040 km2 no sudeste do Brasil. Ao total, 5.4% das árvores mortas foram utilizadas por 14 espécies de aves. O biguá Nannopterum brasilianus (Gmelin, 1789) foi a espécie mais frequente nos paliteiros. As aves frequentemente limparam as penas, descansaram (sem nenhuma atividade aparente), defecaram, caçaram, se alimentaram, vocalizaram e beberam água. Mais atenção deve ser focada em alguns comportamentos das aves tais como o descanso seguido de defecação que podem influenciar processos ecológicos a longo prazo (p. ex., a incorporação de matéria orgânica e mudança de comunidade aquática) na represa.

Water-electricity nexus in Ecuador: The dynamics of the electricity's blue water footprint.

Freshwater has spatial and temporal constraints, affecting possibilities to generate electricity. Previous studies approached this from a water perspective quantifying water consumption of electricity to optimize water use, or from an electricity perspective using modeling methods to optimize electricity output. However, power plants consume different water volumes per unit of electricity, depending on the applied technology, and supply systems often include a mix of different technologies with a different water footprint (WF), an indicator of water consumption, per unit of electricity. When water availability varies in time, probably the contribution of different electricity generating technologies also varies in time, resulting in WF fluctuations. Focusing on electricity generation from the water perspective, we assessed how water availability affects an electricity mix's dynamics and its blue WF using Ecuador as a case study. We studied the Amazon and Pacific basins, which have different temporal and spatial water availability fluctuations, assessing monthly water availability, electricity production, and blue WFs per plant. The Amazon basin has smaller temporal and spatial availability fluctuations than the Pacific. The difference between the largest and smallest water availability in the Amazon basin is two-fold, in the Pacific four-fold. Hydropower generation in the Amazon basin contributes more than 60% to the electricity mix. However, hydropower is directly affected by water availability, and its production decreases in water-limited periods. For biomass plants, limited water availability affects the fuel source, sugarcane bagasse. As water availability decreases, other technologies in the mix take over, causing WF variation (from 4.8 to 8.6 103 m3 per month). Usually, less water-availability means more water-efficiency, implying fossil-fueled plants in the Pacific take over from hydropower in the Amazon. It is relevant to assess the water-electricity nexus in countries with electricity mixes dominated by hydropower because energy planning needs to consider water availability and electricity mix dynamics.

Efectos de la generación de energía hidroeléctrica en la reproducción de Prochilodus magdalenae (Prochilodontidae): evidencia de la respuesta endócrina / Hydropower effects on Prochilodus magdalenae (Prochilodontidae) reproduction: evidence from endocrine response

RESUMEN Objetivo. Describir la respuesta endocrina asociada con la reproducción de un pez potamódromo tropical ante cambios en el régimen de descarga de caudal producido por la generación de hidro-energía en un río Andino. Materiales y métodos. Se analizó la reproducción de Prochilodus magdalenae en individuos de dos sectores de una cuenca neotropical: uno con flujo hidrológico natural y otro con un régimen regulado. Resultados. En la sección de la cuenca con flujo natural, se encontró que la producción de hormonas relacionadas con la reproducción de peces (FSH y LH) estaba correlacionada con el índice gonadosomático, mientras que en peces bajo la influencia del pulso de agua producto de la operación hidroeléctrica esta correlación no fue detectada. Conclusiones. La producción de hormonas asociadas con la reproducción en peces potamódromos fue sensible a cambios en el nivel/caudal. En consecuencia, peces expuestos a las alteraciones en el pulso de caudal estarían recibiendo estímulos ambiguos que afectan la producción de hormonas, la sincronización de la reproducción con las señales ambientales y la maduración, lo cual es esencial para el éxito reproductivo.

ABSTRACT Objective. Describe the endocrine response associated with the reproduction of a tropical potamodromous fish under changes in the flow discharge produced by hydropower in an Andean. Materials and methods. We analyzed Prochilodus magdalenae reproduction in individuals from two sectors of a Neotropical river basin: one with a natural flow and another one with a regulated hydrological regime. Results. In the sector of the basin with the natural flow we found that the production of hormones related with fish reproduction (FSH and LH) was correlated with the gonadosomatic index, while in fish experiencing hydropeaking due to hydroelectric operation no such correlation was detected. Conclusions. Hormone production associated to reproduction of the Potamodromous fish was sensitive to changes in water level and discharge. Then, fish exposed to hydropeaking would be receiving ambiguous stimuli that affect hormone production, reproduction synchronization with environmental cues, and ripening, which are essential for reproductive success.

Massive tree mortality from flood pulse disturbances in Amazonian floodplain forests: The collateral effects of hydropower production.

Large dams built for hydroelectric power generation alter the hydrology of rivers, attenuating the flood pulse downstream of the dam and impacting riparian and floodplain ecosystems. The present work mapped black-water floodplain forests (igapó) downstream of the Balbina Reservoir, which was created between 1983 and 1987 by damming the Uatumã River in the Central Amazon basin. We apply remote sensing methods to detect tree mortality resulting from hydrological changes, based on analysis of 56 ALOS/PALSAR synthetic aperture radar images acquired at different flood levels between 2006 and 2011. Our application of object-based image analysis (OBIA) methods and the random forests supervised classification algorithm yielded an overall accuracy of 87.2%. A total of 9800 km2 of igapó forests were mapped along the entire river downstream of the dam, but forest mortality was only observed below the first 49 km downstream, after the Morena rapids, along an 80-km river stretch. In total, 12% of the floodplain forest died within this stretch. We also detected that 29% of the remaining living igapó forest may be presently undergoing mortality. Furthermore, this large loss does not include the entirety of lost igapó forests downstream of the dam; areas which are now above current maximum flooding heights are no longer floodable and do not show on our mapping but will likely transition over time to upland forest species composition and dynamics, also characteristic of igapó loss. Our results show that floodplain forests are extremely sensitive to long-term downstream hydrological changes and disturbances resulting from the disruption of the natural flood pulse. Brazilian hydropower regulations should require that Amazon dam operations ensure the simulation of the natural flood-pulse, despite losses in energy production, to preserve the integrity of floodplain forest ecosystems and to mitigate impacts for the riverine populations.

Otolith microchemistry and diadromy in Patagonian river fishes.

Coastal habitats in Chile are hypothesized to support a number of diadromous fish species. The objective of this study was to document migratory life histories of native galaxiids and introduced salmonids from a wide latitudinal range in Chilean Patagonia (39-48°S). Otolith microchemistry data were analysed using a recursive partitioning approach to test for diadromy. Based on annular analysis of Sr:Ca ratios, a diadromous life history was suggested for populations of native Aplochiton taeniatus, A. marinus, and Galaxias maculatus. Lifetime residency in freshwater was suggested for populations of A. zebra and G. platei. Among introduced salmonids, populations of Oncorhynchus tshawytscha and O. kisutch exhibited patterns consistent with anadromy, whereas the screened population of O. mykiss appeared restricted to freshwater. Salmo trutta exhibited variable patterns suggesting freshwater residency and possibly anadromy in one case. The capacity and geographic scope of hydropower development is increasing and may disrupt migratory routes of diadromous fishes. Identification of diadromous species is a critical first step for preventing their loss due to hydropower development.

Fishery parameters and population dynamics of silver croaker on the Xingu river, Brazilian Amazon / Parâmetros pesqueiros e dinâmica populacional da pescada branca no Rio Xingu, Pará, Brasil

The study analyzed the fishery parameters and population dynamics of the silver croaker, Plagioscion squamosissimus, and its exploitation status, before the damming of the Xingu River by the Belo Monte hydroelectric dam. Silver croaker was caught throughout the year, with a total production of 239 tons. Estimated Catch per Unit Effort (CPUE) was 14.16 kg.fisher-1.day-1. The mean price paid to the fishers for a kilogram of silver croaker ranged from US$1.89 to US$3.28. Mean longevity estimated was 7.68 years. The total mortality (Z) was calculated at approximately 1.44 year-1, natural mortality (M) was 0.76 year-1, fishery mortality (F) was 0.68 year-1, and the current exploitation rate (E) was 0.47 year-1. The study highlights the importance of P. squamosissimus as a fishery resource in the Xingu region and provides important insights for the development of future fishery management strategies and conservation of the species stocks.(AU)

Este estudo analisa os parâmetros pesqueiros e dinâmica populacional da pescada branca, Plagioscion squamosissimus, e seu status de explotação, antes do barramento do rio Xingu pela hidrelétrica de Belo Monte. A pescada branca foi capturada durante todo o ano, com uma produção total de 239 toneladas. A captura por Unidade de Esforço (CPUE) foi de 14,16 kg.pescador-1.dia-1. O preço médio pago aos pescadores por um quilo de pescada branca variou entre R$ 4,16e R$ 7,21. A longevidade média estimada para a espécie foi de 7,68 anos. A mortalidade total (Z) foi calculada em aproximadamente 1,44 ano-1, a mortalidade natural (M) foi de 0,76 ano-1, a mortalidade da pesca (F) foi de 0,68 ano-1 e a taxa de exploração atual (E) foi de 0,47 ano-1. O estudo destaca a importância de P. squamosissimus como recurso pesqueiro na região do Xingu, e fornece informações importantes para o desenvolvimento de futuras estratégias de manejo pesqueiro e conservação dos estoques de espécies.(AU)

Fishery parameters and population dynamics of silver croaker on the Xingu river, Brazilian Amazon / Parâmetros pesqueiros e dinâmica populacional da pescada branca no Rio Xingu, Pará, Brasil

The study analyzed the fishery parameters and population dynamics of the silver croaker, Plagioscion squamosissimus, and its exploitation status, before the damming of the Xingu River by the Belo Monte hydroelectric dam. Silver croaker was caught throughout the year, with a total production of 239 tons. Estimated Catch per Unit Effort (CPUE) was 14.16 kg.fisher-1.day-1. The mean price paid to the fishers for a kilogram of silver croaker ranged from US$1.89 to US$3.28. Mean longevity estimated was 7.68 years. The total mortality (Z) was calculated at approximately 1.44 year-1, natural mortality (M) was 0.76 year-1, fishery mortality (F) was 0.68 year-1, and the current exploitation rate (E) was 0.47 year-1. The study highlights the importance of P. squamosissimus as a fishery resource in the Xingu region and provides important insights for the development of future fishery management strategies and conservation of the species stocks.

Este estudo analisa os parâmetros pesqueiros e dinâmica populacional da pescada branca, Plagioscion squamosissimus, e seu status de explotação, antes do barramento do rio Xingu pela hidrelétrica de Belo Monte. A pescada branca foi capturada durante todo o ano, com uma produção total de 239 toneladas. A captura por Unidade de Esforço (CPUE) foi de 14,16 kg.pescador-1.dia-1. O preço médio pago aos pescadores por um quilo de pescada branca variou entre R$ 4,16e R$ 7,21. A longevidade média estimada para a espécie foi de 7,68 anos. A mortalidade total (Z) foi calculada em aproximadamente 1,44 ano-1, a mortalidade natural (M) foi de 0,76 ano-1, a mortalidade da pesca (F) foi de 0,68 ano-1 e a taxa de exploração atual (E) foi de 0,47 ano-1. O estudo destaca a importância de P. squamosissimus como recurso pesqueiro na região do Xingu, e fornece informações importantes para o desenvolvimento de futuras estratégias de manejo pesqueiro e conservação dos estoques de espécies.

Hidronegócio em questão: empoderamento dos atores regionais no contexto da descentralização da geração e gestão da energia elétrica / Hydrogen in question: empowering regional actors in the context of the decentralization of the generation and management of electrical energy

O artigo apresenta uma reflexão sobre o modelo centralizado de produção de energia elétrica no Brasil, com destaque para a fonte hidrelétrica, realizada por meio da construção de barragens e usinas, que geram fortes impactos sociais e ambientais. Esse modelo, que opera de forma verticalizada, interligado de norte a sul, fez da energia elétrica uma mercadoria, uma commodity, que favorece o desenvolvimento do Hidronegócio. Dessa forma atende aos interesses de grandes grupos econômicos, empreiteiras, bancos, fornecedoras de equipamentos, grandes consumidores e empresas de consultoria que visam unicamente o aumento dos seus lucros. Para se contrapor a esse modelo, que concentra e exclui, é necessário que ocorra a desconcentração da geração de energia elétrica e o aproveitamento dos potenciais regionais, como a biomassa residual, possibilitando o empoderamento das comunidades, visando a promoção do desenvolvimento regional.

This paper presents a reflection on the centralized model of electric energy production in Brazil, with emphasis on the hydroelectric source, made through the construction of dams and power plants, which generate strong social and environmental impacts. This model, which operates vertically, interconnected from north to south, has made electric energy a commodity, that favors the development of the Hydropower. In this way, it serves the interests of large economic groups, contractors, banks, equipment suppliers, large consumers and consulting companies that only aim to increase their profits. In order to counteract this model, which concentrates and excludes, it is necessary to decentralize the electric energy generation and to promote the use of regional potentials, such as residual biomass, to enable the empowerment of the communities, aiming the promotion of regional development.

The invisibility of fisheries in the process of hydropower development across the Amazon.

We analyze the invisibility of fisheries and inadequacy of fishers' participation in the process of hydropower development in the Amazon, focusing on gaps between legally mandated and actual outcomes. Using Ostrom's institutional design principles for assessing common-pool resource management, we selected five case studies from Brazilian Amazonian watersheds to conduct an exploratory comparative case-study analysis. We identify similar problems across basins, including deficiencies in the dam licensing process; critical data gaps; inadequate stakeholder participation; violation of human rights; neglect of fishers' knowledge; lack of organization and representation by fishers' groups; and lack of governmental structure and capacity to manage dam construction activities or support fishers after dam construction. Fishers have generally been marginalized or excluded from decision-making regarding planning, construction, mitigation, compensation, and monitoring of the social-ecological impacts of hydroelectric dams. Addressing these deficiencies will require concerted investments and efforts by dam developers, government agencies and civil society, and the promotion of inter-sectorial dialogue and cross-scale participatory planning and decision-making that includes fishers and their associations.

Reproduction of two loricariid species in a confined river and implications for environmental impacts of dams

Fish reproduction in floodplain rivers is often linked to flow regime and with the inundation of floodplain habitats. However, in confined rivers, where floodplains are absent, the relation between reproduction and flow can in comparison be expected to be distinct. In this study, we describe the reproductive life-history of Hemiancistrus fuliginosus and Hypostomus isbrueckeri in a confined river and discuss its differences relative to floodplain loricariids and also the implications for effects of dam construction and flow regulation. We found the reproductive peak of both species occurred during lowering waters, just after maximum river flow, in contrast to floodplain species that tend to spawn during rising waters. The studied species presented attributes of equilibrium life-history strategy, which are related to predictable river flow variation. Because both species spawned during low river flow, which is historically predictable in summer, we suggest that their reproduction may be severely disrupted, depending on how flow regime is affected by dam operation. These results have implications for assessing and mitigating the impacts of river damming on fish populations in confined rivers, and we point to ecologically driven flow management and conservation of free-flowing rivers as mitigation and conservation alternatives.(AU)

A reprodução de peixes em rios com planície de inundação está associada ao regime de vazão e sua interação com os hábitats laterais. Entretanto, em rios confinados, sem planícies de inundação, pode-se esperar que a relação entre reprodução e vazão seja comparativamente distinta. Neste estudo, descrevemos as características reprodutivas da história de vida de Hemiancistrus fuliginosus e Hypostomus isbrueckeri em um rio confinado, discutimos as diferenças em relação à reprodução de loricarídeos em planícies de inundação e também as implicações para o efeito de barragens e manejo da vazão de rios. O pico reprodutivo de ambas as espécies ocorreu durante o período de baixa vazão, logo após o período de máxima vazão, contrastando com o padrão observado na reprodução de espécies em planícies de inundação, que ocorre principalmente no período de incremento de vazão. As duas espécies apresentaram história de vida com estratégia de equilíbrio. Pelo fato de ambas espécies desovarem durante a baixa vazão do rio, cuja ocorrência no verão é historicamente previsível, sugerimos que seus padrões de desova podem ser severamente alterados, dependendo de como o regime de vazão for afetado pela operação da barragem. Esses resultados têm implicações para avaliação e manejo de impactos ambientais de barragens em rios confinados, sendo que o manejo ecológico de vazão e a conservação de rios livres de barragens como alternativas de mitigação e conservação, respectivamente.(AU)