References of "Ovidio, Michaël"
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See detailSpawning behaviour and mating success in hybrids of silver bream (Blicca bjoerkna L.) and rudd (Scardinius erythrophthalmus L.) in an experimental environment
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

in Animal Biology (2013), 63

The egg-release, mating, courting and aggressive acts for the spawning behaviour as well as the survival rates after spawning at stages of eyed embryos, viable hatchlings, and larvae to dry food ... [more ▼]

The egg-release, mating, courting and aggressive acts for the spawning behaviour as well as the survival rates after spawning at stages of eyed embryos, viable hatchlings, and larvae to dry food consumption for the mating success were studied in cultured silver bream Blicca bjoerkna × rudd Scardinius erythrophthalmus hybrids at their first sexual maturity. Experiments were conducted in experimental environments simulating natural reproductive conditions of the parental species. Spawning behaviour was analysed over 1 day from 8.00 to 18.00 hours using a remote-controlled video. Mating success was assessed from eggs and hatched embryos collected on the spawning ground. The results showed that these hybrids exhibited all the reproductive behaviours of the parental species with significantly more courtship than mating. Each egg-release act was accompanied by mating behaviour, involving all the experimental males. A surprising aggressive behaviour was observed in one male which attacked all other experimental fish. Successful mating resulted in the presence of fertilized eggs, the production of hatched embryos in experiments, and the survival of larvae at the dry food consumption stage. However, the low viable hatchling rate observed could indicate a very low chance of survival for these hybrids in rivers in which the occurrence of post-F1 individuals may be more possible by backcrossing. [less ▲]

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See detailEvaluation de la qualité biologique des rivières wallonnes sur base des indices biologiques poissons. Support technique aux inventaires 2012.
Rimbaud, Gilles ULg; Ovidio, Michaël ULg; Dierckx, Arnaud ULg et al

Report (2012)

Ce rapport a pour objectif l’évaluation de la qualité biologique des eaux de surface basée sur les indices biologiques « poissons » dans un certain nombre de cours d’eau de Wallonie. Il résulte d’une ... [more ▼]

Ce rapport a pour objectif l’évaluation de la qualité biologique des eaux de surface basée sur les indices biologiques « poissons » dans un certain nombre de cours d’eau de Wallonie. Il résulte d’une convention entre le Service public de Wallonie et l’Université de Liège. [less ▲]

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See detailA comparative study of sexual product quality in F1 hybrids of the bream Abramis brama X the silver bream Blicca bjoerkna
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

in Fisheries Science (2012), 78

The gonadosomatic index at spawning, absolute fecundity, and egg size for the female sexual products as well as the density and consistency of semen for the male sexual products were examined in cultured ... [more ▼]

The gonadosomatic index at spawning, absolute fecundity, and egg size for the female sexual products as well as the density and consistency of semen for the male sexual products were examined in cultured Abramis brama 9 Blicca bjoerkna F1 hybrids and compared with the parental species at their first sexual maturity. Females ovulated under environmental conditions, and their eggs were weighed, counted and measured. Semen of males was macroscopically examined and spermatozoa counted using a hemocytometer. Results revealed that hybridization affected the quality of female and male gametes but with an overlap between hybrids and parents. The gonadosomatic index and fecundity were significantly lower than those of parental species. Egg sizes in hybrids showed a parental effect but to the benefit of hybrids. Semen of hybrids was more diluted which was classified into two groups: the white semen overlapping slightly with parents and the aqueous without any overlap with parents. Overlapped areas between hybrids and parents in term of quality of sexual products could translate that females and males of these hybrids have the biological capacity to produce high quality gametes and thus, a greater chance to produce F2 and backcross generations in rivers. [less ▲]

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See detailBehavioural adaptations of rheophilic fish radio-tracked in a river highly fragmented by hydroelectric plants. Outcomes of a partial reopening of their migration routes.
Ovidio, Michaël ULg; Dierckx, Arnaud ULg; Benitez, Jean-Philippe ULg et al

in Proceedings of the 9th International Conference on Ecohydraulics (2012, September)

Using water resources for hydroelectricity production influences and limits the quality and quantity of habitat available for use by fishes and influences fish mobility. In the Amblève (River Meuse basin ... [more ▼]

Using water resources for hydroelectricity production influences and limits the quality and quantity of habitat available for use by fishes and influences fish mobility. In the Amblève (River Meuse basin, Belgium), the major part of the river is fragmented by hydroelectric power plants that largely prevent the biological movements of the fish population. In 2007, in the hydroelectric site of Lorcé, a modern pool-type fish pass was constructed, re-establishing the upstream movements of fish after more than 80 years of total obstruction. Sixteen different fish species promptly used the new fish pass and the objective of our study was to analyse their behavioural tactics and spawning activity once released upstream of the dam in a previously inaccessible environment. The study focussed on rheophilic holobiotic species, the nase (Chondrostoma nasus), the barbel (Barbus barbus), the European grayling (Thymallus thymallus) and the brown trout (Salmo trutta), which are highly representative of the fish population of the river. The fish were radio-tagged and intensively located using manual tracking techniques during their circum reproduction periods. The results indicate that most individuals of the different species seem to have found usable spawning areas and exploited a large part of the newly usable river stretch (as well as tributaries) located upstream of the fish pass. However, a major problem was observed during the post-spawning period, when the tracked individuals tried to reach their original departure sites (located downstream of the fish pass). The absence of a downstream migration device combined with the passage of all the water through the turbine severely disrupted their post-reproductive movements. [less ▲]

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See detailWhat do we know to evaluate the health of brown trout (Salmo trutta) populations?
Gouraud, Véronique; Baran, Philippe; Bardonnet, Agnès et al

in Proceedings of the 9th International Conference on Ecohydraulics (2012, September)

The renewed emphasis on the concept of the health of ecosystems highlights society’s interest in taking measures to protect environments transformed by human activity. The criteria used for evaluating the ... [more ▼]

The renewed emphasis on the concept of the health of ecosystems highlights society’s interest in taking measures to protect environments transformed by human activity. The criteria used for evaluating the health of fish population are rarely discussed within the scientific community. The exercise proposed here aimed to discuss these for the brown trout (Salmo trutta), a flagship species from the freshwater fish community typical from headwaters of watercourses which represent most of the French hydrographic network. This initiative aimed to gather the ideas of a limited number of experts on the function of these populations and on the criteria for evaluating their function. The main key parameters were identified and organised into a hierarchical framework for each development stage. A consensus emerged on the fact that in the current stage of knowledge, the diagnosis can be established based on the analysis of abiotic parameters crucial for the biology and, with more difficulty, on the analysis of biotic parameters. For all the development stages, the identified parameters are linked to habitat (substrate, stream flow, temperature and water quality), hydrology and connectivity. Further knowledge must be acquired in order to be able to measure the biological criteria. That implies to reinforce longterm biological monitoring and research to understand the variability in biological parameters, the relevant spatiotemporal scales and the functional processes. [less ▲]

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See detailFish responses to artificial flow and water temperature variability in a large river (Rhône, France)
Capra, Hervé; Ovidio, Michaël ULg; Pella, Hervé et al

in Proceedings of the 9th International Conference on Ecohydraulics (2012, September)

Understanding fine scale behavioural responses of fish to changes in abiotic characteristics of habitat, such as flow variability, is an interesting innovative issue to improve river management in highly ... [more ▼]

Understanding fine scale behavioural responses of fish to changes in abiotic characteristics of habitat, such as flow variability, is an interesting innovative issue to improve river management in highly disturbed aquatic environments. For example, in the Rhône River (France), important hydrology and thermal contrasts are mainly explicated by the succession of dams and nuclear power plants. The main aim of our study was to describe fish behaviour in term of movements and habitat use as responses to habitat variability due to the production of peaking electricity and temperature heterogeneity (natural or due to a nuclear power plant release). Fixed telemetry system (accuracy of few square meters; Hydroacoustic Technology Inc.) enabled to define individual fish behavior during different short habitat variability configuration (flow increase, flow decrease, temperature increase....). We then recorded at a local scale continuous movements of n=61 fish during short term (lower than day) habitat variability. The study was conducted in a 2 km long river stretch, from July to September 2009. Abiotic conditions (temperature, depth, velocity or substrate) were simulated (with an accuracy comparable with fish positioning accuracy) every where at any time (i.e. for any discharge) using a hydraulic 2D model calibrated and validated for the whole discharge range observed during the experiment. Three main species were represented : two native cyprinids, chub (Squalius cephalus) and barbel (Barbus barbus), and an invasive species, wels catfish (Silurus glanis). Fish mobility and habitat use were studied to describe changes in behavior associated with changes of abiotic conditions. The separate effects of each environmental factors (discharge, temperature, photoperiod) and their interactions on fish behavioral responses were studied. Finally, variability of fish habitat preferences were estimated to refine understanding of observed behaviors. The different results highlighted the advantages and limitations of the telemetry acoustic system in a large river to address fish displacement in response to discharge and temperature variability. They also emphasized the necessity of a 2D hydrodynamic model to understand fish behaviour. [less ▲]

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See detailEscapement success and patterns of downstream migration of female silver eel Anguilla anguilla in the River Meuse
Verbiest, Hilde; Breukelaar, André; Ovidio, Michaël ULg et al

in Ecology of Freshwater Fish (2012), 21

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See detailModélisation hydrodynamique et télémétrie : vers de nouvelles connaissances pour l'écologie des poissons du Rhône
Capra, Hervé; Ovidio, Michaël ULg; McNeil, Eric et al

in IS Rivers Extended Abstract book (2012, June)

The article presented herein aims to demonstrate how a two-dimensional hydrodynamic model representing abiotic conditions can be used to study the behaviour of fish affected by large fluctuations of ... [more ▼]

The article presented herein aims to demonstrate how a two-dimensional hydrodynamic model representing abiotic conditions can be used to study the behaviour of fish affected by large fluctuations of environmental conditions in the Rhône River. This represents a major advancement in the understanding of aquatic community structures and in particular, for the structure of fish communities that are rarely used in France. For the first time, the environmental conditions affecting fish and their spatial localization will be simultaneously known. The model can also simulate habitat conditions and water temperatures over longer time frame. For example, this methodology is compatible with the monitoring of fish communities of the Rhône River, which was initiated in 1979. The interest in modeling precise habitat and temperature conditions with hydrodynamic models for a large array of flows allows one to consider the role that these two key environmental factors play on fish behaviour. [less ▲]

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See detailReproductive performance in F1 hybrids of two phytophilous cyprinid fish, the silver bream (Blicca bjoerkna) x the rudd (Scardinius erythrophthalmusl
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

in Program and Abstracts of the XIV European Congress of Ichthyology (2012, June)

Reproductive performance including the spawning behaviour and quality of gametes in cultured F1 hybrids of two phytophilous cyprinid fish species, the silver bream Blicca bioerkno x rudd Scardinius ... [more ▼]

Reproductive performance including the spawning behaviour and quality of gametes in cultured F1 hybrids of two phytophilous cyprinid fish species, the silver bream Blicca bioerkno x rudd Scardinius erythrophtalmus was investigated in this study at their first sexual maturity. The spawning behaviour was studied in terms of egg release, courting and mating acts under reproductive conditions between hybrids or mixed with the silver bream males. Behavioural experiments were conducted in experimental environments simulating natural reproductive conditions of the species using the spawning ground, high temperature, mixing of sex, natural photoperiod and no hormonal injections. The quality of gametes was evaluated by analysing egg production, sperm density, and F2 and backcross offsprings. For the egg production, the gonadosomatic index, absolute fecundity and egg diameters were analysed at spawning. sperm density was estimated by counting spermatozoa in a hemocytometer. F2 and backcross offsprings were produced from eggs of the female hybrid fertilised with the sperm of a corresponding hybrid male and a male silver bream. The results revealed that these hybrids exhibited all the reproductive behaviours of the parental species with an intense courting activity. Each egg-release act was accompanied by mating activity, involving simultaneously and successively all the experimental males, hybrids and silver bream, resulting in fertilised eggs. The quality of female sexual products was close to that found in parental species. However, the male sexual products were found more diluted, and F2 generations produced with a significantly lower hatching rate than backcrosses. This study has proven that these FL hybrids have the capacity to exhibit all the reproductive behaviour as observed in the wild population of parental species. These hybrids are fertile and thus biologically viable. ln rivers, their backcrossed offsprings have a greater chance of occurring than F2 progeny. [less ▲]

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See detailEscapement Success And Patterns Of Downstream Migration Of Female Silver Eel Anguilla Anguilla In The River Meuse
Verbiest, Hilde; Breukelaar, André; Ovidio, Michaël ULg et al

Poster (2012, May)

Downstream migration of female silver eel Anguilla anguilla (L.) was studied by remote telemetry in the lower part of the River Meuse (Belgium and The Netherlands) using a combination of 9 detection ... [more ▼]

Downstream migration of female silver eel Anguilla anguilla (L.) was studied by remote telemetry in the lower part of the River Meuse (Belgium and The Netherlands) using a combination of 9 detection stations and manual tracking. N=31 eels (LT 64-90cm) were implanted with active transponders and released in 2007 into the River Berwijn, a small Belgian tributary of the River Meuse, 326 km from the North Sea. From August 2007 till April 2008 13 eels (42%) started their downstream migration and were detected at two or more stations. Mean migration speed was 0.62 m.s-1 (or 53 km.day-1). Only two eels (15%) arrived at the North Sea, the others being held up or killed at hydroelectric power stations, caught by fishermen or by predators or stopped their migration and settled in the river delta. A majority (58%) of the eels classified as potential migrants did not start their migration and settled in the River Berwijn or upper Meuse as verified by additional manual tracking. [less ▲]

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See detailProbability of detection and positioning error of a hydro acoustic telemetry system in a fast-flowing river: intrinsic and environmental determinants
Bergé, Julien; Capra, Hervé; Pella, Hervé et al

in Fisheries Research (2012), 125-126

In situ fixed acoustic telemetry methods make it possible to study simultaneously the detailed movements of individual fish and their relationship to the environment, but the properties of these methods ... [more ▼]

In situ fixed acoustic telemetry methods make it possible to study simultaneously the detailed movements of individual fish and their relationship to the environment, but the properties of these methods is little known in harsh physical conditions. We examined the probability of tag detection by the system and the positioning error for detected tags of an existing telemetry system installed with 32 fixed hydrophones in a reach of the fast-flowing Rhône River in France. The reach was 1.8 km long and had heterogeneous thermal and hydraulic conditions described by a two-dimensional hydraulic model. We compared positions detected by the system with true positions estimated using a tachometer or a differential GPS, for various sets of experimental tag emissions. We analyzed how the probability of detection and the positioning error were affected by user-defined variables and three groups of environmental variables describing the configuration of the hydrophones around tag position, the physical environment at tag position and the reception quality. Tag emissions from the center channel had an average probability of detection (40-50%) higher than emissions originating from positions close to the banks, and were positioned with smaller average errors (3-5 m). The probability of detection of emissions typically varied between near 0% and 80% with configuration variables (density of surrounding hydrophones and location of tag relative to the hydrophones) and also decreased in the presence of coarse substrate. The positioning error was mainly reduced when user-defined variables of the triangulation software were set by an expert user. Configuration variables also influenced the positioning error with weaker effects than those observed for detection probability. [less ▲]

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See detailEssai d’estimation des dommages piscicoles engendrés par les prises d’eau industrielles et les turbines hydroélectriques dans les cours d’eau de la Province de Liège. Partie C. Le cours principal de l’Amblève non navigable.
Philippart, Jean-Claude ULg; Ovidio, Michaël ULg; Rimbaud, Gilles ULg et al

Report (2011)

Ce rapport à la Commission provinciale de Liège du Fonds piscicole de Wallonie est un dossier bibliographique qui analyse l’impact sur les populations de poissons des centrales hydroélectriques (CHE ... [more ▼]

Ce rapport à la Commission provinciale de Liège du Fonds piscicole de Wallonie est un dossier bibliographique qui analyse l’impact sur les populations de poissons des centrales hydroélectriques (CHE) installées sur le cours principal de l’Amblève non navigable. Il s’agit d’un grand cours d’eau (module du débit : 20 m3/s dans le cours inférieur à Martinrive-Aywaille) constitué de zones à ombre et à truite qui abritent une importante biodiversité piscicole dont notamment des poissons migrateurs amphihalins comme l’anguille européenne, la truite de mer et le saumon atlantique en cours de réintroduction en Wallonie.L’évaluation des impacts piscicoles des CHE se limite à une approche très préliminaire consistant à apprécier de manière théorique (par rapport à des modèles élaborés en France) les ordres de grandeur des entraînements vers les turbines et des mortalités des populations migratrices (surtout les anguilles argentées et les smolts de Salmonidés) attendues sur les différents sites, compte tenu des caractéristiques connues des prises d’eau (grilles), des turbines (Kaplan, Francis, Banki ; grandeur des roues, vitesse de rotation, débit turbiné), de la taille des poissons et des possibilités de dévalaison par une voie autre (déversoir de barrage, exutoire de dévalaison) que le passage dans les turbines. Partant de ces premiers résultats, le rapport détaille les actions à entreprendre sur chaque site hydroélectrique pour le rendre moins pénalisant pour les poissons migrateurs en dévalaison et dans certain cas, en montaison comme à la cascade de Coo. Il propose aussi quelques recommandations générales applicables à l’évaluation objective de l’impact piscicole de tout site hydroélectrique et à l’atténuation de cet impact. Ainsi, en matière biologique et piscicole, il apparait prioritaire de mettre en place des programmes d’études permettant : i) de caractériser qualitativement (taille des poissons et périodicité des mouvements) et surtout quantitativement (effectifs numériques et biomasse) les migrations de dévalaison des principales espèces cibles dans les cours d’eau concernés des zones à ombre et à truite et ii) d’estimer les mortalités réelles des poissons dans les différents types d’installation de production d’hydroélectricité. [less ▲]

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