Evaluación biológica de escalas de artesas para algunas de las principales especies de peces Ibéricos

Son muy pocos los estudios que evalúen y aseguren el buen funcionamiento de las escalas de peces. Por todo ello, con este trabajo, se ha profundizado en una metodología y análisis de resultados que puedan servir de guía para tal fin. Se ha utilizado tecnología de telemetría PIT-tag, centrándose en los movimientos ascendentes de los peces. Las escalas en las que se ha trabajado han sido del tipo “artesas”, localizadas en la cuenca del Duero. Se ha observado que los ciprínidos ibéricos estudiados tienen una capacidad de ascenso muy similar a la trucha y que los tiempos de ascenso no han supuesto retrasos importantes a la migración. También se ha analizado el efecto de las variables ambientales y la influencia de la longitud del pez. Se espera que este trabajo sirva de apoyo en futuras evaluaciones biológicas y los resultados reviertan en la mejora del diseño de escalas.Instituto Universitario de Investigación en Gestión Forestal SostenibleDoctorado en Ciencia e Ingeniería Agroalimentaria y de Biosistema

Session D7: The Most Evaluated Fishway in Spain: A New Lesson Every Year

Abstract: Salto de San Fernando” hydropower plant is placed at River Tormes, just upstream of Santa Teresa reservoir (Salamanca, Spain). The dam is 13 m high and it has a pool and weir with bottom orifice fish ladder to let potamodromous fish (Iberian barbel – Luciobarbus bocagei–, Nothern straightmouth nase –Pseudochondrostoma duriense– and brown trout –Salmo trutta–) overcome the obstacle. This fish ladder is being monitored since 2012: daily trapping and counting fish that reach the last pool; fish passage video recording through orifices and spillways; tagging fish (PIT, Tbar and others) and studying passage metrics (location, entrance, passage time, performance). Results have been analyzed as a function of physical –discharge, temperature, atmospheric pressure– and biological variables –species, sex, size, competition–. Downstream migration is also analyzed to locate fish routes and understand fish behavior. After every research, passage improvement options are detected, accomplished and assessed on next migration season. At this moment, this overall approach has quintupled fish ladder efficiency and it offers lot of information about Iberian fish behavior and their preference under different hydraulic conditions

Fishways as downstream routes in small hydropower plants: Experiences with a potamodromous cyprinid

Producción CientíficaFish need to move upstream and downstream through rivers to complete their life cycles. Despite the fact that fishways are the most commonly applied solution to recover longitudinal connectivity, they are not considered viable for downstream migration. Therefore, alternative facilities are recommended to facilitate downstream migration. However, a few recent studies have disagreed with this general assumption, showing the potential for bidirectional movements. This study advances our understanding of the potential of fishways for downstream migration by studying their efficiency in a run-of-the-river hydropower plant in the Duero River (Spain). To achieve this, downstream movements of the Iberian barbel (n = 299) were monitored in a stepped fishway for two years with passive integrated transponder (PIT)-tag technology, considering the effect of fish origin and release zone. The results showed that 24.9% of barbels descended through the fishway, with the origin and release zone affecting the fishway location. In addition, downstream movements were observed throughout the whole year, except in winter. The study concludes that, under specific scenarios, fishways could act as safe alternative routes for downstream migration.Unión Europea H2020 - (grant 727830)Ayudas Torres Quevedo - (grants PTQ2018-010162 and PTQ2016-08494)Universidad de Valladolid - (grant PIF-UVa 2017

Fishway attraction efficiency during upstream and down-stream migration: field tests in a small hydropower plant with run-of-the-river configuration

Producción CientíficaUnderstanding fishway attraction is one of the main open challenges in fishways research, and unraveling the mechanisms and relationships that trigger it is crucial to improve the performance of fishways. Furthermore, attraction is usually understood in terms of upstream migration; however, taking into account the possible bidirectional use of fishways, it is equally important to study this phenomenon during downstream migration, although this is usually considered negligible. Therefore, this study aims to advance our understanding of fishway attraction efficiency by considering both upstream and downstream movements in a key small hydropower plant scheme in the Iberian Peninsula. To achieve this, one of the most common Iberian fish species, the Iberian barbel (Luciobarbus bocagei, Steindachner), was monitored via telemetry in a stepped fishway. The studied fishway, considering the specialized literature, would be classified as poor in attraction, i.e., difficult to find due to its low competing discharge and the long distance between the main river flow and both fishway entrances. Fish were PIT tagged and released in different upstream and downstream locations and on different dates. The results showed that a significant proportion of the tagged barbels was able to successfully locate the fishway from both sides, in spite of the mentioned localization drawbacks, with inter-annual variability and with repeated events throughout the years. This suggests that even a fishway with a theoretical poor attraction can still be localized by fish, allowing their use as a two-way migration route, at least with species and HPP schemes such as those already studied

Effect of thermo‐velocity barriers on fish: influence of water temperature, flow velocity and body size on the volitional swimming capacity of northern straight‐mouth nase (Pseudochondrostoma duriense)

Producción CientíficaWater temperature and flow velocity directly affect the fish swimming capacity, and thus, both variables influence the fish passage through river barriers. Nonetheless, their effects are usually disregarded in fishway engineering and management. This study aims to evaluate the volitional swimming capacity of the northern straight-mouth nase (Pseudochondrostoma duriense), considering the possible effects of water temperature, flow velocity and body size. For this, the maximum distance, swim speed and fatigue time (FT) were studied in an outdoor open-channel flume in the Duero River (Burgos, Spain) against three nominal velocities (1.5, 2.5 and 3 m s−1) and temperatures (5.5, 13.5 and 18.5°C), also including the changes between swimming modes (prolonged and sprint). Results showed that a nase of 20.8 cm mean fork length can develop a median swim speed that exceeds 20.7 BL s−1 (4.31 m s−1) during a median time of 3.4 s in sprint mode, or 12.2 BL s−1 (2.55 m s−1) for 23.7 s in prolonged mode under the warmest scenario. During prolonged swimming mode, fish were able to reach further distances in warmer water conditions for all situations, due to a greater swimming speed and FT, whereas during sprint mode, warmer conditions increased the swim speed maintaining the FT. In conclusion, the studied temperature range and flow velocity range influence fish swimming performance, endurance and distance travelled, although with some differences depending on the swimming mode. The provided information goes a step forward in the definition of real fish swimming capacities, and in turn, will contribute to establish clear passage criteria for thermo-velocity barriers, allowing the calculation of the proportion of fish able to pass a barrier under different working scenarios, as well designing of the optimized solutions to improve the fish passage through river barriers.Junta de Castilla y León (proyecto VA299B11-2)Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 10103202

Upstream movement capacity of invasive signal crayfish (Pacifastacus leniusculus) under different environmental and biometric factors

Producción CientíficaThe spread of invasive crayfish species is a major threat to endemic species worldwide. This threat affects native crayfish as well as flora and fauna species in general. In order to limit their dispersal, different methods have been used, the most promising of which are those related to physical barriers. For their design, it is essential to know the limits in the capacity of crayfish to move under different hydraulic scenarios, although to date, there are few studies on this topic. The present work analyzes the volitional upstream movement capacity of the signal crayfish (Pacifastacus leniusculus) in a laboratory open flume, with different configurations of environmental and hydraulic variables (bed roughness, flow velocity, water temperature, times of day) and accounting for the possible effect of biometric factors (carapace length, sex). Twenty-four different trials with five individuals per trial were carried out, tracking all crayfish movements individually by visual tags and with a video monitoring system. Data were analyzed using survival analysis techniques and parametric models were developed, considering as response variables the maximum distance traveled and the movement speed. The results showed that the combination of bed roughness and flow velocity were the best predictors to explain crayfish movement performance, with a flow velocity greater than 0.8 m/s together on a non-rough bed being the limiting factor; the water temperature and the sex also have a significant effect. This information can serve as a basis for the design of future barriers to the dispersal of invasive crayfish species in the Iberian Peninsula

Bidirectional connectivity in fishways: A mitigation for impacts on fish migration of small hydropower facilities

Producción Científica1.Most freshwater fish need to move freely through rivers to complete their lifecycles. Thus, river barriers (e.g. dams, culverts and gauging stations) may delay,hinder or even block their longitudinal movements, affecting fish conservation.The most widespread solution to allow upstream fish migration are fishways,whereas downstream migration is basically facilitated through spillways, turbinesor specific solutions such as bypass systems.2. So far, studies and scientific discussions concerning bidirectional movementsthrough fishways are scarce and focused on large dams and reservoirs, mainlywith large migratory species such as salmonids, rather than smaller facilities andlesser known species.3. This study investigated bidirectional movements through a small run-of-the-riverhydropower plant with a pool-and-orifice type fishway, using the Iberian barbel(Luciobarbus bocagei), a potamodromous cyprinid, as the target species. Passiveintegrated transponder and radio tracking data were collected over 4 years andcombined to characterize upstream and downstream movements. The studyfocused primarily on fish movements through the fishway, but also estimated themultiple associated routes of passage.4. The results show diverse fish movements with inter- and intra-annual variability,with several individuals performing bidirectional movements and even some fishreturning over the years.5. The documented movements and observations indicate that fishways can serveas an effective bidirectional migration corridor for fish, potentially enhancing theconservation efforts for potamodromous species. This study supports thedecision to use fishways as an overall mitigation tool to reduce the impact ofsmall hydropower facilities on fish.European Union’s Horizon 2020 research and innovation program. grant agreement no.727830European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no.10103202

Two-way migration of a potamodromous cyprinid in a small hydropower plant with a pool type fishway

Producción CientíficaMost freshwater fish need to move freely through rivers to complete their life cycles. Thus, river barriers that hinder or block their longitudinal movement (e.g., dams, culverts, gauging stations), directly affect their reproductive, feeding, and habitat routes. A holistic solution to these barriers would need to allow directed, undistracted, and bidirectional fish migration between different habitats; that is to say, it would need to allow two-way migration. The most extended solution that would allow upstream fish migration is a fishway. However, for downstream migration fish have alternate routes such as spillways, turbines, or bypasses. Studies and discussions about two-way migration and bidirectional movement through a fishway have been focused on large dams and reservoirs; thus, there is a lack of available data on other environments, less popular species, or smaller dams and weirs. In this sense, it is possible to hypothesize that a fishway, especially in a smaller facility, could enhance two-way migration by allowing bidirectional movement. Therefore, as a first step to analyzing the possibility, we studied longitudinal connectivity (two-way migration and bidirectional movements) through a small run-of-river hydropower plant (HPP) with a step-pool type fishway, a common and representative configuration of several small HPPs around the world. A potamodromous cyprinid—the Iberian barbel (Luciobarbus bocagei)—was selected as the target species. In this study, radio and PIT tracking data were collected for four different years and combined to characterize movement in the full system: fishway, turbines/spillways, and the river reach downstream (up to 3 km) and upstream (up to 4 km) from the HPP. The results demonstrated the existence of several types of movement with inter-annual and intra-annual variability. Several fish even returned over the years. This suggests that, in this type of HPP facility, a fishway can provide bidirectional connectivity and two-way migration, thus ensuring that a great proportion of fish complete their life cycles.European Union’s H2020 - (grant 727830, FIThydro

Turning pools in stepped fishways: Biological assessment via fish response and CFD models

Producción CientíficaWith the aim of building more compact fishways and adapting them to field conditions to improve their location by fish, it is common to use turning pools, reducing the longitudinal development of the construction. However, depending on their design, turning pools may affect the hydraulic performance of the fishway and consequently the fish passage. To study these phenomena, turning pools in a vertical slot and in different configurations of submerged notches with bottom orifice fishway types were assessed. Both types of fishways were studied using numerical 3D models via OpenFOAM, a computational fluid dynamics software, in combination with fish responses, assessed with PIT (Passive Integrated Transponder) tag telemetry for three different species of potamodromous cyprinids in several fishways. Results show differences between the hydrodynamics of straight and turning pools, with lower values in the hydrodynamic variables in turning pools. Regarding fish behavior, the ascent was slower in turning pools but with no effect on passage success and without being a problem for fish migration. This information validates the use of turning pools as a key design component for fishways for studied species.Ayudas Torres Quevedo - (grants PTQ2018-010162 and PTQ2016-08494)Unión Europea H2020 - (grant 727830

Fish upstream passage through gauging stations: experiences with Iberian barbel in Flat-V Weirs

Producción CientíficaThe monitoring of river discharge is vital for the correct management of water resources. Flat-V gauging weirs are facilities used worldwide for measuring discharge. These structures consist of a small weir with a triangular cross-section and a flat “V”-shaped notch. Their extensive use is a consequence of their utility in the measurement of both low and high flow conditions. However, depending on their size, local morphology and river discharge can act as full or partial hydraulic barriers to fish migration. To address this concern, the present work studies fish passage performance over flat-V weirs considering their hydraulic performance. For this, radio-tracking and video-monitoring observations were combined with computational fluid dynamics (CFD) models in two flat-V weirs, using Iberian barbel (Luciobarbus bocagei) as the target species. Results showed that fish passage is conditioned by both hydraulic and behavioral processes, providing evidence for scenarios in which flat-V weirs may act as full or partial barriers to upstream movements. For the studied flat-V weirs, a discharge range of 0.27–8 m3/s, with a water drop difference between upstream and downstream water levels lower than 0.7 m and a depth downstream of the weir of higher than 0.3 m can be considered an effective passage situation for barbels. These findings are of interest for quantifying flat-V weir impacts, for engineering applications and for establishing managing or retrofitting actions when required.European Union’s Horizon 2020 (Grant 101032024