Marine and Freshwater Research
Volume 69
Number 12 2018
Fish Passage 2018 & Hydropower Symposium
Fish and hydropower are often in conflict. The need to produce energy often comes at the expense of fisheries productivity. This has led to a global effort in research to understand and mitigate development impacts and sustain this important research.
This study aims to assess the upstream and downstream passage performance of the Iberian barbel (Luciobarbus bocagei), when facing a small broad-crested experimental weir with varying widths of the weir crest (W), and discharges (Q). Results varied among the configurations tested, emphasising the complex influence of factors on passage performance of barbel. The outcomes of this work may be useful to identify potential migration obstacles for medium-sized potamodromous cyprinids.
Hydropower and irrigation development threatens the long-term sustainability of Indonesia’s unique and important inland fisheries by blocking important migration pathways. Blocked fish may be affected because they are unable to feed, spawn or access important habitat. There has been significant recent interest in developing engineering solutions to help overcome these potential impacts. Fishways, channels around or through a migration barrier, are one such solution that has had enormous success internationally. However, technology is largely untested in Indonesia and there is an urgent need for locally focussed research.
We evaluated the stress and metabolic responses of the streaked prochilod, Prochilodus lineatus, during the passage through a fish ladder in the Paraná River, Brazil. The results suggested presence of metabolic alterations, mainly for small fish, but not stress. Physiological indicators are helpful tools to assess the passing of long-distance migratory fish through fishways, aiming adoption of good management practices.
This telemetry study demonstrated that co-location of low-head hydropower with a fish pass facilitates high attraction efficiency for upstream migrating sea trout. The probability of passage and passage delay were influenced by downstream river level and river flow but not by the hydropower operation. These findings will enable development of guidelines for improvement of fish passes at low-head hydropower schemes.
This review has provided a summary of knowledge on two-way fish migration of salmonids and eels past hydroelectric plants in Europe. General designs and recommendations for best practices for fish-pass facilities are provided. We generally recommend (1) using ramps, nature-like channels and vertical-slot fishways for these species and (2) reducing water drop between the pools in pool-and-weir fishways for trout and grayling, compared with the design of traditional Atlantic salmon ladders. For safe downstream fish migration, we generally recommend a combination of physical blocking structures in front of hydropower intakes, such as fine-mesh trash racks with alternative escape routes and bypass arrangements.
We evaluated fish-ladder effectiveness at Porto Primavera Dam in the Paraná River, for two Neotropical migratory fish species in ascending and descending direction. The entry rate was low for both species, especially for fish from upstream. However, once the fish entered into the fishway, the success rate was high in both directions.
Near nature-like fish by-pass systems can function as an important habitat for the conservation of the remaining native riverine fish fauna. The heterogenic configuration of the Danube by-pass system in Vienna-Freudenau provides conditions for a broad range of fish species from all life stages, including eggs, larvae, juveniles and adults. Finally, approved management tools are discussed.
We evaluated total project survival for fish moving downstream past a small hydropower facility located on the Upper Mississippi River in Minnesota, USA. Survival rates were developed from a desktop model that incorporated estimates of spillway and gate passage, intake trash-rack impingement, and turbine entrainment and survival. The results indicated that it was unlikely that the operation of the project was affecting local fish populations.
Efficient bypasses are necessary to ensure safe downstream passage of migrating fish at hydropower plants. We reviewed literature for efficient design criteria of surface bypasses and suggest a list of parameters for bypass-performance studies. Considering this list in future bypass-performance studies can help perform meta-analyses on bypass performance and improve bypass design considerations.
Hydropower dams disrupt longitudinal connectivity, which has led to declines in migratory fish species. We assessed the performance of two fish passage solutions for Atlantic salmon smolts and documented improved passage conditions at the site, confirming angled racks with bypasses as best-practise solutions for downstream passage, but also that large nature-like fishways may act as downstream passage routes for salmon.
This study compared fish monitoring data simultaneously recorded by ARIS sonar, GoPro camera and a multi-mesh stow net from fish downstream passage. Because there is a lack of knowledge about the accuracy of sonar- and camera-based fish counts and identification, we compared the recorded number, length and species composition among the different monitoring approaches.
We evaluated, under laboratory conditions, the effects of pressure changes in the Amazonian catfish Pimelodus pictus, simulating passage through turbines. Fish remained negatively buoyant in the pressure chamber and even low ratios of pressure change caused severe injuries. These findings corroborated the need to diversify species for barotrauma experiments and better understand buoyancy in benthic species.
Experiments conducted with the Pictus catfish showed that the current hypo-hyperbaric chambers used to study barotrauma in nektonic species can have limitations when applied to benthic fish. This study discusses these limitations and present potential methods to overcome them. Diversification of approaches for barotrauma studies with benthic species is critical to provide information for the development of effective mitigation measures.
Hydraulic and physical conditions through three different low-head turbines (very low head (VLH), Archimedes screw and horizontal Kaplan) were assessed using an autonomous sensor. All turbines displayed conditions that could injure fish migrating downstream. Strike events were common at the VLH and screw turbine, and decompression, strike and shear observed at the Kaplan turbine.
This study documents the behavioural effects, injuries and mortality rates of blue gourami (Trichopodus trichopterus) and iridescent sharks (Pangasianodon hypophthalmus) resulting from shear forces, similar to what they might experience during hydroturbine passage. For both species, the occurrence of negative effects increased with the severity of shear forces. To minimise impacts on these species, the operation and design of hydroturbines in their native river systems should strive to minimise the occurrence of these critical limits.
Barotrauma can occur in fish from exposure to rapid decompression associated with downstream passage through hydraulic structures. To predict injury and mortality resulting from barotrauma, four Australian fish species were exposed to a range of decompressions simulating downstream passage through hydraulic structures. Fish were then assessed so that dose–response models could be developed for application to current and future infrastructure.
The fish movement downstream dams may be affected by hydropower plant operation. We used a numerical flow model to understand possible velocity barriers in water for neotropical fish and the effect of each turbine on these barriers. The results showed no velocity barrier for some important neotropical fish and may support mitigation decisions in the South America.
The rapid and ongoing expansion of hydropower on large river systems globally has compromised fisheries and affected rural livelihoods and food security. This paper explores the proposal to develop a hydropower scheme on the Kafue River in Zambia, how it will potentially affect the downstream aquatic ecosystem and options for optimising the dam’s operational procedures to protect the fisheries and wildlife for future generations.
This study has highlighted potential impacts of reservoir cascades on fish diversity, which must be carefully considered in river-basin inventories for hydropower plants, and reinforce the importance of long-term monitoring. Reduction in richness of native and migratory fish following reservoir formation and longitudinal gradient of diversity along the cascade was observed. Important predictors of variation in fish-assemblage structure were assessed, including non-native fish species.
Trap-and-haul of adult salmon is a conservation strategy in regulated rivers, but better protocols are needed to ensure effectiveness. We demonstrated that Chinook salmon released into a cold-water reservoir had lower thermal exposure than did salmon released into a warm-water tributary where prespawn mortality has been episodically high. The strategy may be effective in dammed rivers with stressful water temperatures.
