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See detailRehabilitation effort for anadromous salmonids in the river Meuse basin. Achievements and new challenges
Ovidio, Michaël ULiege; Kestemont, Patrick; Dierckx, Arnaud ULiege et al

Conference (2019, May)

Until the end of the 19th century, the Atlantic salmon (Salmo salar) was widespread in the river Meuse basin and salmon fisheries were prosperous in France, Belgium and The Netherlands. The number of ... [more ▼]

Until the end of the 19th century, the Atlantic salmon (Salmo salar) was widespread in the river Meuse basin and salmon fisheries were prosperous in France, Belgium and The Netherlands. The number of salmon and sea trout captures reaches 57000 ind/year in the Dutch Rhine-Meuse delta. Between 1840 and 1950, the building of navigation dams in the river Meuse and its tributaries, as well as the increase of industrial water pollution and the overexploitation of the stock, led to the extinction of all anadromous fish species. In 1983, the capture of a sea trout (Salmo trutta) in the lower Belgian Meuse brought the problem of the migratory of fish to the surface. Based on scientific advices and feasibility studies carried out from 1983 to 1986, the program Salmon Meuse was launch in 1987. It aims at the restoration of the complete life cycle of migratory salmonids in the international River Meuse Basin. Important rehabilitation efforts have been progressively done since the beginning of the project to the present 1) Improvement of the general quality of the water 2) Restocking with strains originating from France, Ireland, Scotland 3) Hydromorphological restoration of gravel bed habitats 4) The construction of modern fishways for upstream migration in the Meuse and tributaries 5) Adoption of measures to facilitate downstream migration at hydroelectric sites 6) Development of a salmon hatchery with facilities to realise artificial reproduction using returning adults 7) The establishment of international collaboration network 8) The election of the best strains based on genetics of returning adults and the process of smoltification finally 9) The opening of the Haringvliet sluices in the Estuary of the Meuse in the Netherland in 2018. In the year 2000, the first adult salmon originating from restocking program was captured in the fishway of Lixhe, and this return of a salmon, more than 50 years of his extinction, was a major ecological event. From 2000 to 2018, the number of returning Atlantic salmon and sea trout progressively increased and reaches n=60 in the best year. This underline partial achievement of the objectives of the project, but the number of returning adult is sill too low to have a natural sustainable population. Supplementary efforts must be undertaken in the future, especially in terms of success of smolts downstream migration and escapement success as well as an optimization of the restocking practices (in terms of quantity and choice of the best development stage). During our talk, we will synthesise the major key-points of this challenging project whose success requires a balance between the development and maintenance of numerous human activities and the associate preservation of the aquatic environment. We will use examples of results originating from recent scientific research. [less ▲]

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See detailWhat happens to glass eels after restocking in upland rivers? A long‐term study on their dispersal and behavioural traits
Nzau Matondo, Billy ULiege; Séleck, Emilie; Dierckx, Arnaud ULiege et al

in Aquatic Conservation (2019)

The European eel Anguilla anguilla is a critically endangered fish species as a result of human activities and climate change in river and oceanic ecosystems. Restocking using glass eels in continental ... [more ▼]

The European eel Anguilla anguilla is a critically endangered fish species as a result of human activities and climate change in river and oceanic ecosystems. Restocking using glass eels in continental freshwater areas is a potential conservation measure for enhancing local eel stocks and for conserving the species in aquatic habitats, where it may otherwise disappear. However, little is known about the fate of these restocked individuals and the early ecological behaviour of the young eels translocated in rivers.A portable radio‐frequency identification (RFID) telemetry system and 12‐mm tags were used to track restocked eels for a duration of 4 years. The aim was to understand the early movement, behavioural traits, dispersal, and habitat use of elvers after restocking performed in 2013 with glass eels in a shallow riverine environment.From the 241 tagged eels (total length, Q50 = 152 mm), 85% were detected in 1968 positions during a period of 4 years, beginning in 2014. Clear seasonality in eel activity was observed, with higher mobility in summer when the water temperature was high (above 12°C). Dispersal was slowed by numerous artificial obstacles and the high carrying capacity of habitats. There was a negative relationship between the body size of eels at tagging and their mobility. Five behavioural categories of mobility patterns were identified: ascending, descending, oscillating with an upstream trend, oscillating with a downstream trend, and stationary. The first four categories depleted with time, in favour of stationary individuals that displayed a highly sedentary lifestyle.This study provides new knowledge of the long‐term dispersal behaviour of restocked eels and the influence of seasons, barriers, and habitats on their colonization strategy changing with time. The results contribute to a better understanding of the issue of uncommon restocking practices in upland rivers. [less ▲]

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See detailEvaluation de la qualité biologique des rivières wallonnes sur base des indices biologiques poissons
Dierckx, Arnaud ULiege; Benitez, Jean-Philippe ULiege; Rimbaud, Gilles ULiege et al

Report (2018)

Ce document reprend les informations recueillies dans le cadre d’un travail effectué par l’Université de Liège pour le compte du Service public de Wallonie-DEMNA et financé dans le cadre d’un marché ... [more ▼]

Ce document reprend les informations recueillies dans le cadre d’un travail effectué par l’Université de Liège pour le compte du Service public de Wallonie-DEMNA et financé dans le cadre d’un marché public de services qui a pour objectif l’évaluation de la qualité biologique des eaux de surface basée sur les indices biologiques « poissons » dans seize cours d’eau de Wallonie. [less ▲]

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See detailMovement behaviours of potamodromous fish within a large anthropised river after the reestablishment of the longitudinal connectivity
Benitez, Jean-Philippe ULiege; Dierckx, Arnaud ULiege; Nzau Matondo, Billy ULiege et al

in Fisheries Research (2018), 207

Human activity has caused longitudinal fragmentation of many rivers. Fishways have been installed worldwide, but their successive use by potamodromous species remains poorly documented, particularly in ... [more ▼]

Human activity has caused longitudinal fragmentation of many rivers. Fishways have been installed worldwide, but their successive use by potamodromous species remains poorly documented, particularly in large river ecosystems. Four vertical slot fishways were installed within a 32-km stretch of the lower Belgian Meuse River basin. From 2012 to 2016, n=532 individuals belonging to 11 potamodromous fish species (rheophilic, limnophilic and large carnivorous) were continuously captured in the most downstream fishway (M0), tagged with an RFID transponder and released upstream. These could be further detected in upstream river part within three fishways (M1 and M2 in the Meuse, and O1 in an important tributary, the Ourthe) that were equipped with RFID detection stations. In the first downstream stretch (13 km from M0 to M1) we quantified an ascending rate until M1 (number of individuals detected in M1/ number of individuals tagged in M0) of 32.9% including all individuals tagged, with a maximum value of 67.2% for chub (Squalius cephalus), 40% for pike (Esox Lucius) and 35.5% for nase (Chondrostoma nasus), and a progression time M0 to M1 of 1.1 days per kilometre (d/km), with trout (Salmo trutta) as the fastest species (0.3 d/km). Upstream of the M1 fishway, many individuals of rheophilic species (trout and barbel, Barbus barbus) preferred to enter in the Ourthe tributary (detection at the Ourthe fishway) unlike the upstream Meuse (detection at the most upstream fishway in the Meuse), demonstrating a new accessibility to more adapted spawning sites. Most fish were present within fishways mainly in spring during the circum-spawning migration, and during summer and autumn for dispersal and/or seeking-refuge. The diel activity cycle varied depending on the species, with detection during the entire diel cycle (e.g. chub and barbel), during the day (e.g. trout) and during the night (e.g. catfish, Silurus glanis). The installation of fishways in the degraded river Meuse can be considered adequate for the restoration of the free movement because potamodromous species demonstrated their ability to migrate over long distances (> 20 km) and to reach potential spawning habitats through the reopened access to a tributary. [less ▲]

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See detailEtude du franchissement de 3 passes à poissons sur la Vesdre aval en 1° catégorie
Watthez, Quentin; Goffaux, Delphine; Sonny, Damien et al

Report (2018)

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See detailRapport de convention sur la Réhabilitation du Saumon Atlantique dans le bassin de la Meuse
Ovidio, Michaël ULiege; Dierckx, Arnaud ULiege; Benitez, Jean-Philippe ULiege et al

Report (2018)

Le présent rapport d’activités intègre les travaux des deux équipes universitaires de Namur et de Liège dans la cadre de la convention relative à la réhabilitation du saumon atlantique dans le bassin de ... [more ▼]

Le présent rapport d’activités intègre les travaux des deux équipes universitaires de Namur et de Liège dans la cadre de la convention relative à la réhabilitation du saumon atlantique dans le bassin de la Meuse. [less ▲]

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See detailThe use of behavioural metrics to evaluate fishway efficiency
Ovidio, Michaël ULiege; Sonny, Damien; Dierckx, Arnaud ULiege et al

in River Research and Applications (2017), 33(9), 1484-1493

Fishways are installed worldwide to facilitate accessibility to functional habitats and to increase the ecological continuity of rivers. Their evaluations are increasing, but complete studies in the field ... [more ▼]

Fishways are installed worldwide to facilitate accessibility to functional habitats and to increase the ecological continuity of rivers. Their evaluations are increasing, but complete studies in the field with wild individuals are still scarce. In the lower Bocq River (Belgium), a pool type fishway was installed in 2011. A combined passive‐integrated‐transponder‐tag and radio‐telemetry system was designed and installed downstream of the dam and in the fishway to analyse fine‐scale individual fish behaviour. Three fish species (brown trout, European grayling, and barbel) were captured in the river; n = 125 fish were tagged and released downstream of the fishway. Behavioural metrics were proposed and used in order to attain a comprehensive view on the efficiency of the fishway, including attraction and entrance efficiency, searching and passage delays, and overall and adjusted passage efficiency. The results indicate a major problem in terms of attraction efficiency (48.9% for the trout, 20.5% for the grayling, and 41.2% for the barbel) and time to find the entrance of the fishway (mean 65.1 hr for the trout and 538.9 r for the grayling). For fish that succeed to approach the entrance of the fishway, the passage efficiency was 86.9% for the trout, 55.5% for the grayling, and 7.1% for the barbel. The time taken to cross the structure was reasonable for the salmonids (mean < 1.5 hr for trout and grayling) but very long (21 hr) for the barbel. Our results underline the necessity of a holistic approach to evaluate fishway efficiency using precise comprehensive metrics and hydraulic characterization. [less ▲]

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See detailA field quantification of all inclusive fish-pass efficiency using a combined telemetry system
Ovidio, Michaël ULiege; Sonny, Damien; Dierckx, Arnaud ULiege et al

Conference (2017, July)

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See detailLong-term monitoring of European eels in the Belgian Meuse River basin. From the historical drastic decline to recent outcomes of restocking practices.
Nzau Matondo, Billy ULiege; Dierckx, Arnaud ULiege; Benitez, Jean-Philippe ULiege et al

Conference (2017, June)

Long-term monitoring of yellow- and glass eel stages were performed in upland areas (>300km from sea) in order (i) to quantify the decline of wild yellow eels entering in the Belgian Meuse from the ... [more ▼]

Long-term monitoring of yellow- and glass eel stages were performed in upland areas (>300km from sea) in order (i) to quantify the decline of wild yellow eels entering in the Belgian Meuse from the Netherlands; (ii) to follow their upstream individual colonization; and (iii) to analyze the adaptation of young eels stocked as glass eels imported from UK. By monitoring a fish pass from 1992 to 2016, we quantified that the number of ascending eels has declined from n=5613 in 1992 to n=21 in 2016 (3.99%/year) and the mean length of eels has increased (4.1mm/year). During 6-years, upstream individual colonization of eels (2010-2015, n=1371) was followed using fixed RFIDtracking system. Few eels continued to migrate 4 years after tagging (<0.3%) and at >20km upstream (3.7%); and velocity of eels varied between individuals (0.012- 3.1km/day). In a 4-year (2013-2016) monitoring study of restocked glass eels using electrofishing and mobile RFID-tracking campaigns, we observed that eels grew rapidly in upland small brooks and recruitment was better in rivers with high carrying capacity (>15.8%, 2years post-stocking). Restocked eels dispersed in up- and downstream directions with behaviors including sedentary, nomadic and intermediate lifestyles. This suggests stocking as potential management measure to enhance local eel stocks. [less ▲]

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See detailPoor Performance of a Retrofitted Downstream Bypass Revealed by the Analysis of Approaching Behaviour in Combination with a Trapping System
Ovidio, Michaël ULiege; Dierckx, Arnaud ULiege; Bunel, Sarah et al

in River Research and Applications (2017), 33

The implementation of fish downstream migration bypass systems is still a major challenge, and there is interest in validating the adequacy of different configurations of bypass devices. In the Amblève ... [more ▼]

The implementation of fish downstream migration bypass systems is still a major challenge, and there is interest in validating the adequacy of different configurations of bypass devices. In the Amblève River (Belgium), a mobile 3.3-m height dam feeds two principal Francis and one Francis micro-turbine and is equipped with a modern vertical slot fish pass and a downstream bypass. The aim of this study was to test the bypass attraction and efficiency (i.e. percentage of fish that approach the entrance and use the bypass) for Atlantic salmon smolts. During three consecutive years, a total of 1346 smolts were equipped with a radio frequency identification tag and released from March to May upstream of the dam of Lorcé. The entrance of the downstream migration bypass was equipped with a radio frequency identification antenna in order to detect the smolts approaching. In 2014, a capture cage was also placed downstream the bypass to evaluate its efficiency. The mean percentage of detected smolts at the entrance varied from 26.2 to 39.7%. In 2014, 16.5% of the released smolts entered the bypass and were finally caught in the cage, representing 39% of the smolts detected at the entrance. More than 98% of the detections occurred during night (mainly between 9 PM and 3 AM). The searching delay near the bypass entrance varied from less than 5 min to more than 5 days (median 4.3 min). Visual observation indicated a behavioural reluctance before entering the bypass, with a shift from positive to negative rheotaxy. Our results underline the difficulty to install retrofitted bypass system on old existing hydropower plants. Copyright © 2016 John Wiley & Sons, Ltd. [less ▲]

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See detailAssessment of the entering stock, migration dynamics and fish pass fidelity of european eel in the belgian meuse river
Nzau Matondo, Billy ULiege; Benitez, Jean-Philippe ULiege; Dierckx, Arnaud ULiege et al

in River Research and Applications (2017), 33

Migration dynamics of incoming eels in Belgium via Lixhe in the Meuse River were investigated using two fish passes with different configurations— net traps and automatic detection stations—as tools to ... [more ▼]

Migration dynamics of incoming eels in Belgium via Lixhe in the Meuse River were investigated using two fish passes with different configurations— net traps and automatic detection stations—as tools to distinguish resident and migrating eels. From April to September 2013, 435 eels (P50 length, 403 mm; range, 196–836 mm) were caught (daily maxima catch, 90 eels per day), 90% between 13 June and 1 August (50 days) and P50 on 19 July. Eels migrated mostly at 19–26 °C (P50, 24.4 °C), river discharge 65–314m3 s 1 (P50, 84m3 s 1), during the dark at 00:00–05:00 h and during both the waxing and waning phases of moonlight. From 396 eels tagged and released 0.3 km downstream of the Lixhe dam, 6.8% of them were recaptured, and 37.4% were detected. Migration flux was estimated at 7184 eels (0.863 t) using the markrecapture method and decreased to 1156 eels (0.139 t) using automatic transponder detection. Most eels probably migrated through a sluice located downstream of Lixhe to reach the upper Meuse via the Albert Canal. Eels moved almost independently to the configuration of the fish passes and their location, but most eels displayed fidelity to the fish pass where they were captured. Migrant eels showed a wide range of size and life stages, with a higher proportion of eels (80%) belonging to the yellow eel stage. A lower proportion of eels (6%) had a larger size and presented an advanced continental silvering process corresponding to the migrating stage before their transatlantic migration. Copyright © 2016 John Wiley & Sons, Ltd. [less ▲]

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See detailConvention relative à la réhabilitation du Saumon atlantique dans le bassin de la Meuse (Rapport 2015-2016)
Ovidio, Michaël ULiege; Dierckx, Arnaud ULiege; Benitez, Jean-Philippe ULiege et al

Report (2016)

Le présent rapport d’activités intègre les travaux des deux équipes universitaires de Liège et de Namur (coordination Ulg – Dr M. Ovidio) dans la cadre de la subvention relative à la réhabilitation du ... [more ▼]

Le présent rapport d’activités intègre les travaux des deux équipes universitaires de Liège et de Namur (coordination Ulg – Dr M. Ovidio) dans la cadre de la subvention relative à la réhabilitation du saumon atlantique dans le bassin de la Meuse. [less ▲]

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See detailIs adult translocation a credible way to accelerate the recolonization process of Chondrostoma nasus in a rehabilitated river?
Ovidio, Michaël ULiege; Hanzen, Céline; Gennotte, Vincent ULiege et al

in Cybium (2016), 40(1), 43-49

The decline of the patrimonial rheophilic nase, Chondrostoma nasus (Linnaeus, 1758) populations was mainly caused by construction of dams and hydroelectric power-plants, together with the straightening ... [more ▼]

The decline of the patrimonial rheophilic nase, Chondrostoma nasus (Linnaeus, 1758) populations was mainly caused by construction of dams and hydroelectric power-plants, together with the straightening and artificialization of the river banks and water pollution. In this study, we tested the hypothesis whether the translocation of few adult nase individuals from a river stretch to another upstream may be a credible way to accelerate the recolonization process of the species in the Amblève River (Southern Belgium). In February and March 2011, just before their spawning period, eight adult nases (462-509 mm; 1546-2002 g; presumed males and females) were captured in the lower part of the River Amblève. Fin clip samples were stored in alcohol for further genetic analysis. They were equipped with a 14 g radio transmitter and translocated upstream in a 18 km river stretch, where the species had disappeared since decades due to river anthropization. They were manually located two to five times/week using mobile receivers until maximum June 2012 (n = 977 locations). River temperature and flow were hourly recorded during the entire tracking period. The tagged nase individuals displayed various mobility patterns, exploited different areas of the river stretch, occupied longitudinal home ranges from 3.4 to 36.1 km (one individual finally left the new river stretch) and travelled total distances from 12.2 to 186.6 km. The tagged individuals were most of the times apart from one to another, but most individuals grouped together in potential spawning areas in late March-early April 2011, suggesting an attempt to reproduce. In September 2011, electric fishing in two potential detected spawning sites allowed to capture 16 juvenile (0+) nases, demonstrating the existence of spawning activity in the newly occupied river stretch. Individual genetic characterization was performed in 2014 in order to reveal a possible direct lineage between juveniles and adults. Allelic distribution of 22 microsatellite markers unambiguously identified the 16 juveniles as full-sib progeny descending from two of the translocated adults. This demonstrated that the adult nases succeeded to find spawning areas and that progeny found raised-up from the translocated individuals. [less ▲]

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See detailAn overview of potamodromous fish upstream movements in medium-sized rivers, by means of fish passes monitoring
Benitez, Jean-Philippe ULiege; Nzau Matondo, Billy ULiege; Dierckx, Arnaud ULiege et al

in Aquatic Ecology (2015), 49(4), 481-497

This study aims to investigate the upstream movement patterns of potamodromous fish species using multi-annual monitoring of modern multi-species fish passes in two medium-sized Belgian rivers: the ... [more ▼]

This study aims to investigate the upstream movement patterns of potamodromous fish species using multi-annual monitoring of modern multi-species fish passes in two medium-sized Belgian rivers: the Berwinne and the Amble`ve. During a 6-year monitoring period including a frequency of 1–5 times per week, the captured individuals were identified, measured and weighed to determine species abundance, and the periodicity of their seasonal movement patterns was investigated in relation to environmental factors. In the Amble`ve, 22 different fish species were monitored (n = 1513 individuals; biomass of 154 kg) and 14 species in the Berwinne (n = 3720; 408 kg). In both fish passes, inter-annual differences were observed, but the first year of monitoring was the best in terms of biomass, indicating the existence of an opening effect just after the fish passes opening, which allowed new migration routes. Salmonids and rheophilic cyprinids were predominant in terms of biomass, while minnow and spirlin were predominant in terms of number of fishes. The diversity in sizeranged from 46 to 760 mm demonstrating the importance of movements in various life stages. The capture periodicity showed different mobility patterns between the adult and juvenile stages in most species. Movements occurred frequently during the circus reproduction period for some species, but many species moved also apart from spawning period. This study highlights the omnipresence of patrimonial holobiotic potamodromous fish at different life stages that reflect their biological needs to move throughout the annual cycle. They must be considered as target species in river continuity restoration programmes and fish-pass design. [less ▲]

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