Evaluation of the performance of successive multispecies improved fishways to reconnect a rehabilitated river

Abstract

The equipping of barriers with fishways has useful applications for testing hypotheses of fish migration and connectivity in river networks, but multiple passage performance for potamodromous fish is poorly known to date. The aim of this study was to analyse the performance of new fishways installed in the river Vesdre (Belgium). Thirty-eight barbel (Barbus barbus; mean: 508 mm, 2133 g) and seven chub (Squalius cephalus; mean: 372 mm, 935 g) were captured by electric fishing and fish pass monitoring and were equipped by RFID-tags and/or radio-transmitters. They were translocated downstream of three different fishways (nature-like pool-type, block ramp, and technical pool-type) in the lower course of the Vesdre. Detection antennas connected to automatic receivers were placed downstream and upstream of each fishway to evaluate the approaching rate, the overall and adjusted passage efficiencies, the passage delays, temperature, dates and time period. The best passage performance and passage delays were observed for the block ramp fishway (88%; 9 h median time to pass) in comparison with pool structures (47 and 73%; 94 and 144 h median time to pass, respectively). The overall passage efficiency was 18.2 and 29.4% for two successive fishways, and 18.2% for three fishways. Passages occurred mainly during dark periods at median temperatures of 14°C (barbel) and 12.3°C (chub), and during highly variable flow conditions. This study provided evidence of the success rate of the reestablishment of the ecological continuity in the river Vesdre as a result of the construction of improved fish-passage structures.

Improving bypass performance and passage success of Atlantic salmon smolts at an old fish-hostile hydroelectric power station: a challenging task

“…Among the diverse set of methods suitable for field analysis of migration at hydropower stations, biotelemetry is recognized as an efficient tool (Ovidio et al, 2017a(Ovidio et al, , b 2020Wilkes et al, 2018a). Depending on the research budget, the size of the fish, the environment, the objectives in terms of sampling effort and the degree of details on searching behaviour, several methods can be used: presence/absence or 2D and 3D acoustic telemetry (e.g.…”

“…Physical obstructions are recognized as major factors influencing the migrations, population structures, spawning success and recruitment of freshwater organisms by preventing or limiting access to formerly available functional habitats (Fullerton et al, 2010;Nunn and Cox, 2012;Benitez et al, 2015;(Ovidio and Philippart, 2002) Ovidio et al, 2020). In addition, hydropower turbines represent a major problem for downstream migrating fish, causing direct or delayed mortality due to passage through turbines, as well as delays for fish that need to migrate long distances (Fjeldstad et al, 2012;Buysse et al, 2015).…”

Assessment of Fish Abundance, Biodiversity and Movement Periodicity Changes in a Large River over a 20-Year Period

“…River fragmentation by dams causes physicochemical and hydromorphological modifications of upstream and downstream habitats, hydropeaking, alterations to the river's natural flow, and obstruction to sediment and biological organisms such as fish and invertebrates [2][3][4]. In an ecosystem where fish fauna represents an important functional element, it is imperative to re-establish connectivity to allow each species to complete its life cycle [5][6][7], because these barriers fragment previously natural rivers and can thus preclude movement between functional habitats [8,9]. The complete Environments 2022, 9, 22 2 of 22 removal of obstacles would constitute the ideal scenario, but this is typically complicated to implement due to the presence of numerous social and usage constraints [4,10].…”

Trying to choose the less bad route: Individual migratory behaviour of Atlantic salmon smolts (Salmo salar L.) approaching a bifurcation between a hydropower station and a navigation canal

“…In highly fragmented environments, the success of migrations is dependent on the performance of the up-and downstream fish-passage structures and mitigation and management measures to facilitate smolt and adult movements (Katopodis and Williams, 2012;Williams et al, 2012;Fjeldstad et al, 2018). Significant progress has been made in fishway design to restore the upstream migration of different fish species, including Atlantic salmon adults, with some that have demonstrated good performance (Benitez et al, 2018;Silva et al, 2018;Ovidio et al, 2020). On the other hand, the re-establishment of a successful and quick downstream migration often remains difficult and challenging in anthropised rivers (Holbrook et al, 2011;Fjeldstad et al, 2012;Newton et al, 2019;Ovidio et al, 2021).…”