References of "Ovidio, Michaël"
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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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See detailDescription of Fish Mobility and Habitat Use in a Large Regulated Fast Flowing River (the Rhône River, France) Using Fine Scale Acoustic Tracking
Bergé, Julien; Capra, Hervé; Pella, Hervé et al

Conference (2011, September)

Understanding fine scale behavioral responses of fish to changes in abiotic characteristics of streams (in term of flow and water temperature) is an interesting innovative issue to improve river ... [more ▼]

Understanding fine scale behavioral responses of fish to changes in abiotic characteristics of streams (in term of flow and water temperature) is an interesting innovative issue to improve river management of highly disturbed large rivers. Acoustic telemetry system have become an essential technology for such studies involving continuous (per second) and accurate tracking of fish movements. In the Rhône River (France), important hydrology and thermal contrasts are mainly explicated by the succession of dams and nuclear power plant from the Leman Lake (Switzerland). In this context, it is likely that fish are compelled to adapt their behaviour and their habitat selection in this changing environment. In order to test this hypothesis, a fixed acoustic telemetry survey was performed in the Rhône River during summer 2009 in front of the Bugey nuclear power plant which released warmed water within the river. A study site of 1.8 km long and 140 m wide was monitored using 32 hydrophones developed by HTI® (Hydroacoustic Technology Inc.). Sixty two fish mainly belonging to three species barbel (Barbus barbus), chub (Leuciscus cephalus) and wels catfish (Silurus glanis) were marked with acoustic tags (307 KHz; pulse rate ~ 3 sec.) and followed continuously during 89 days. Fish positions were coupled with a 2D hydraulic model to obtain main physical characteristics encountered by fish such as flow velocity, water depth, water temperature and substrate. The accuracy of the telemetry system was checked and a positional error less than 4 m was found in the channel (detection efficiency of 50 %) and less than 8 meters along the banks (detection efficiency of 20 %). Behavioral responses of fish were investigated through the individual mobility and activity during selected phases of flow (increase, decrease and stability) and water temperature changes (imposed by both warm water plumes and the rapid transition of deep cold waters from the Leman Lake discharged within the river). Mobility and activity of fish were particularly studied to determine the amount of movement associated with a change of abiotic conditions. The separate effects of each environmental factors on behavioral responses of fish were studied and interactions between factors were analyzed to highlight potential synergistic or antagonistic effects. Finally, movement rules (i.e. individual movement decisions in a particular surrounding environment) were analyzed to determine the role of perception of the environment by fish (i.e. how the fish feel the changes in physical habitat) in the use of space. [less ▲]

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See detailUse of Fixed and Mobile Acoustic Telemetry Systems to Understand Fish Responses to Habitat Variability in a Large River (Rhône, France)
Capra, Hervé; Pella, Hervé; Ovidio, Michaël ULg et al

Conference (2011, September)

The presentation would summarize the advantages and limitations of both fixed and mobile acoustic telemetry equipment deployed in a fast flowing large river : the Rhône river (France). The objectives were ... [more ▼]

The presentation would summarize the advantages and limitations of both fixed and mobile acoustic telemetry equipment deployed in a fast flowing large river : the Rhône river (France). The objectives were to describe fish behavior in term of fish movements as responses to habitat variability due to the production of peaking electricity and temperature heterogeneity (natural or due to a nuclear power plant release). At a local scale we used a fixed automatic acoustic telemetry system to record continuous movements of n=62 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. In a 35 km long study site, we used a mobile acoustic telemetry system to record weekly position of n=108 fish over different seasons and different habitat conditions (low or high flows; low or high temperature...), from March to December 2010. Discharge and abiotic conditions (temperature, depth, velocity or substrate) were known (with an accuracy comparable with fish positioning accuracy) every where at any time (i.e. any discharge) using hydraulic 2D model calibrated and validated for the whole discharge range observed during telemetry studies. Fixed telemetry system (accuracy of few square meters) enabled to define individual habitat use during different short habitat variability configuration (flow increase, flow decrease, temperature increase....). Three main species were represented : two native cyprinids, chub (Leuciscus cephalus) and barbel (Barbus barbus), and an invasive species, wels catfish (Silurus glanis). We analyzed habitat used, habitat preference, fish movement patterns versus habitat variability. Mobile telemetry system (accuracy of few hundred square meters) enabled to evaluate space and time utilisation of fish (mainly the same species than for fixed telemetry study) at a larger scale and during different seasons encompassing the reproduction period, the summer or the winter periods. The different results obtained by both telemetry systems will be presented to illustrate the advantages and limitations of those systems in a large river to address fish displacement in response to discharge and temperature variability. This comparison also emphasized the contribution of a 2D hydrodynamic model to understand fish behaviour. [less ▲]

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See detailReproductive behaviour and sexual production in the first-generation hybrids of roach Rutilus rutilus L. x common bream Abramis brama L
Nzau Matondo, Billy Nzau; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

in Journal of Applied Ichthyology (2011), 27(3), 859-867

The aim of this study was to further test the viability of the roach Rutilus rutilus · common bream Abramis brama hybrid in terms of reproductive behaviour and sexual production. Egg release, mating and ... [more ▼]

The aim of this study was to further test the viability of the roach Rutilus rutilus · common bream Abramis brama hybrid in terms of reproductive behaviour and sexual production. Egg release, mating and aggressive acts in reproductive behaviour, as well as absolute fecundity and sperm density in milt for sexual production were examined in the first generation of these hybrids at their first sexual maturity. The F2 and backcrosses of hybrids were also studied. The results revealed that these hybrids expressed a normal and typical mating behaviour, producing viable gametes. Under experimental reproduction between hybrids (hybrid reproduction), the number of egg-release acts (range, 21–66) was nearer (v2 test, P > 0.05) the number of mating acts (11–65). Moreover, hybrid males exhibited territorial and aggressive behaviours. However, in experimental reproduction of female and male hybrids mixed with parental males (mixed reproduction), the egg-release act and the mating act were inhibited by the intense territorial and aggressive activities of the common bream male. Absolute fecundity values (median, <2.2 · 103 eggs) and sperm density (<7 · 109 spermatozoa ml)1) of hybrids showed a greater decrease (U test, P < 0.05) than in parental species (median, >6.0 · 103 eggs and >14 · 109 spermatozoa ml)1, respectively). Nevertheless, these hybrids were fertile. F2 and backcross generations were produced, although with a significantly lower viable hatching rate (FEP test, P < 0.05) in F2 individuals from the female and its corresponding hybrid male (<6%), indicating a very low chance of survival in rivers. [less ▲]

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See detailStratégies de reproduction et structure des populations chez Labeo parvus (cypriniformes: cyprinidae) dans le bassin du fleuve Ouémé au Bénin
Montchowui, Elie; Ovidio, Michaël ULg; Laleye, Philippe et al

in Annales des Sciences Agronomiques du Bénin (2011), 15(2), 153-171

La stratégie de reproduction et la structure des populations chez Labeo parvus ont été étudiées dans le bassin du fleuve Ouémé (Bénin) entre avril 2005 et mars 2006. Les poissons ont été capturés ... [more ▼]

La stratégie de reproduction et la structure des populations chez Labeo parvus ont été étudiées dans le bassin du fleuve Ouémé (Bénin) entre avril 2005 et mars 2006. Les poissons ont été capturés mensuellement par des pêcheurs professionnels au moyen de filets maillants. Les filets sont posés le soir et relevés le lendemain matin. La structure démographique de L. parvus a été examinée sur la base de la distribution des fréquences de tailles. La stratégie de reproduction a été étudiée à partir de l’indice gonadosomatique (IGS), la structure ovarienne et la fécondité. Les populations de L. parvus présentent une structure par tailles de type bimodal. Le premier mode est représenté par les juvéniles 0+ (≤ 9 cm LT) issus de la reproduction de l’année. Le deuxième mode est constitué des géniteurs (13-28 cm LT). Sur 1088 specimens collectés dans le fleuve Ouémé, 14,9% sont des juvéniles (< 9 cm LT), 6% pré-adultes (9-13 cm LT) et 79,1% adultes (> 13 cm LT). L’analyse de la structure ovarienne montre un développement synchrone des ovocytes avec la présence de deux cohortes conduisant à une ponte. La saison de reproduction est comprise entre juillet et octobre correspondant à la crue fluviale maximale dans le bassin avec une forte fécondité (8723 à 124363 ovules). L. parvus est une espèce potamodrome, géniteur synchrone qui se concentre dans le fleuve avant de migrer pendant les crues fluviales dans les plaines inondables pour pondre. [less ▲]

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