16 research outputs found
Impacts Ă©cologiques des Ă©clusĂ©es hydroĂ©lectriques. CaractĂ©risation des rĂ©gimes dâĂ©clusĂ©es et Retour dâexpĂ©rience sur la Maronne
Les Ă©clusĂ©es hydroĂ©lectriques peuvent impacter de maniĂšre consĂ©quente les populations de poissons, et plus particuliĂšrement compromettre le recrutement des espĂšces diadromes comme le saumon. Pour progresser dans la comprĂ©hension des impacts et la dĂ©finition des mesures de mitigation, il sâavĂšre nĂ©cessaire de coupler des suivis biologiques long-terme, une analyse hydrologique avec une caractĂ©risation des rĂ©gimes dâĂ©clusĂ©es, ainsi quâune approche hydromorphologique. Une mĂ©thodologie de caractĂ©risation hydrologique des rĂ©gimes dâĂ©clusĂ©es est dans un premier temps prĂ©sentĂ©e. Leur diversitĂ© et leur importante variabilitĂ© sont illustrĂ©es. On prĂ©sente ensuite le retour dâexpĂ©rience acquis sur la Maronne, cours dâeau affluent de la Dordogne en aval dâArgentat soumis aux Ă©clusĂ©es de lâamĂ©nagement de Hautefage. Les suivis biologiques et les Ă©tudes hydrologiques et hydromorphologiques ont permis de mieux apprĂ©hender et quantifier certains impacts (exondations de frayĂšres, Ă©chouages-piĂ©geages dâalevins), dâĂ©tayer des mesures de mitigation et dâen Ă©valuer lâefficacitĂ©. LâintĂ©rĂȘt de travaux ponctuels sur la morphologie en complĂ©ment des mesures sur la gestion des dĂ©bits est Ă©galement illustrĂ©. Des rĂ©sultats positifs ont dĂ©jĂ Ă©tĂ© obtenus. Les rĂ©flexions se poursuivent sur la Maronne pour obtenir une situation vraiment satisfaisante. Cet exemple montre que lâĂ©tat actuel des connaissances ne permet pas, sur un cours dâeau donnĂ©, de prĂ©dĂ©finir des mesures de mitigation des impacts des Ă©clusĂ©es, tout en garantissant leur efficacitĂ©. Cela amĂšne Ă prĂŽner la mise en place de dĂ©marche dâĂ©tude similaire sur dâautres cours dâeau, pour identifier les rĂ©ponses des communautĂ©s biologiques en fonction des caractĂ©ristiques des Ă©clusĂ©es et des hydrosystĂšmes
What do we know to evaluate the health of brown trout (Salmo trutta) populations?
peer reviewedThe renewed emphasis on the concept of the health of ecosystems highlights societyâs 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
Hydropeaking impacts on the Dordogne river Definition of mitigation measures and assessment of their efficiency
Hydropeaking impacts on the Dordogne river Definition of mitigation measures and assessment of their efficienc
Assessment of control factors and sensitivity of a river channel to changes based on a combination of historical and field data, the middle Dordogne River, France
International audienc
Assessment of control factors and sensitivity of a river channel to changes based on a combination of historical and field data, the middle Dordogne River, France
International audienc
Problématique des impacts écologiques engendrés par les éclusées hydroélectriques. Caractérisation des régimes d'éclusées. Retour d'expérience sur le cas de la Maronne.
Issue of ecological impacts due to hydropeaking management. Characterization of hydropeaks - Operating experience on Maronne river.
Hydropeaking management can consistently alter fish populations, and particularly recruitment of diadromous species, like salmon. To progress in understanding the impacts and defining mitigation measures, it appears essential to combine long-term biological survey, hydrological analysis including hydropeaks characterization and hydromorphologic approach. In a first time, a methodology for hydrological characterization of hydropeaks is presented. Their diversity and high variability are illustrated. Then, we present operating experience on Maronne River, a tributary of the Dordogne River downstream Argentat affected by hydropeaks of Hautefage scheme. Biological surveys and hydrologic and hydro-morphologic studies alloweds a better understanding and a quantification of some biological impacts (redds dewatering, stranding-trapping of alevins), to support mitigation measures and to assess its effectiveness. The relevance of work on morphology, in addition to measures on flow management, is also illustrated. Despite some positive results, the situation on the Maronne River is not yet satisfactory. This example shows that the current state of knowledge does not allow, on a given stream, to predefine mitigation measures and ensure their efficiency. This leads to advocate the setting up of similar approach on other rivers.Les Ă©clusĂ©es hydroĂ©lectriques peuvent impacter de maniĂšre consĂ©quente les populations de poissons, et plus particuliĂšrement compromettre le recrutement des espĂšces diadromes comme le saumon. Pour progresser dans la comprĂ©hension des impacts et la dĂ©finition des mesures de mitigation, il sâavĂšre nĂ©cessaire de coupler des suivis biologiques long-terme, une analyse hydrologique avec une caractĂ©risation des rĂ©gimes dâĂ©clusĂ©es, ainsi quâune approche hydromorphologique. Une mĂ©thodologie de caractĂ©risation hydrologique des rĂ©gimes dâĂ©clusĂ©es est dans un premier temps prĂ©sentĂ©e. Leur diversitĂ© et leur importante variabilitĂ© sont illustrĂ©es. On prĂ©sente ensuite le retour dâexpĂ©rience acquis sur la Maronne, cours dâeau affluent de la Dordogne en aval dâArgentat soumis aux Ă©clusĂ©es de lâamĂ©nagement de Hautefage. Les suivis biologiques et les Ă©tudes hydrologiques et hydromorphologiques ont permis de mieux apprĂ©hender et quantifier certains impacts (exondations de frayĂšres, Ă©chouages-piĂ©geages dâalevins), dâĂ©tayer des mesures de mitigation et dâen Ă©valuer lâefficacitĂ©. LâintĂ©rĂȘt de travaux ponctuels sur la morphologie en complĂ©ment des mesures sur la gestion des dĂ©bits est Ă©galement illustrĂ©. MalgrĂ© certains rĂ©sultats positifs, la situation sur la Maronne nâest pas encore satisfaisante. Cet exemple montre que lâĂ©tat actuel des connaissances ne permet pas, sur un cours dâeau donnĂ©, de prĂ©dĂ©finir des mesures de mitigation des impacts des Ă©clusĂ©es, tout en garantissant leur efficacitĂ©. Cela amĂšne Ă prĂŽner la mise en place de dĂ©marche dâĂ©tude similaire sur dâautres cours dâeau.Courret Dominique, Larinier Michel, Chanseau Mattieu, Lascaux Jean-Marc. ProblĂ©matique des impacts Ă©cologiques engendrĂ©s par les Ă©clusĂ©es hydroĂ©lectriques. CaractĂ©risation des rĂ©gimes d'Ă©clusĂ©es. Retour d'expĂ©rience sur le cas de la Maronne.. In: 32Ăšmes JournĂ©es de lâHydraulique de la SociĂ©tĂ© Hydrotechnique de France Environnement et HydroĂ©lectricitĂ© Lyon - 6 et 7 octobre 2010. 2010
Evaluation des facteurs de contrÎles des ajustements morphologiques récents (20Úme siÚcle) de la Dordogne dans sa moyenne vallée, France
International audienc
Redundancy analysis, genome-wide association studies, and the pigmentation of brown trout (Salmo trutta L.)
International audiencePigmentation variation in the polytypic brown trout (Salmo trutta) has an unknown genomic basis. Using redundancy analyses and genome-wide association studies, authors showed that pigmentation has a large polygenic basis in this species, based on hundreds of loci known to be associated to colour. Redundancy analysis also showed that backcrossed wild trout converged to a locally adaptive Mediterranean pigmentation pattern despite the release of Atlantic hatchery fish
Development of a large SNPs resource and a low-density SNP array for brown trout (Salmo trutta) population genetics
International audienceBackground: The brown trout (Salmo trutta) is an economically and ecologically important species for which population genetic monitoring is frequently performed. The most commonly used genetic markers for this species are microsatellites and mitochondrial markers that lack replicability among laboratories, and a large genome coverage. An alternative that may be particularly efficient and universal is the development of small to large panels of Single Nucleotide Polymorphism markers (SNPs). Here, we used Restriction site Associated DNA sequences (RADs) markers to identify a set of 12,204 informative SNPs positioned on the brown trout linkage map and suitable for population genetics studies. Then, we used this novel resource to develop a cost-effective array of 192 SNPs (96 Ă 2) evenly spread on this map. This array was tested for genotyping success in five independent rivers occupied by two main brown trout evolutionary lineages (Atlantic-AT-and Mediterranean-ME-) on a total of 1862 individuals. Moreover, inference of admixture rate with domestic strains and population differentiation were assessed for a small river system (the Taurion River, 190 individuals) and results were compared to a panel of 13 microsatellites. Results: A high genotyping success was observed for all rivers (< 1% of non-genotyped loci per individual), although some initially used SNP failed to be amplified, probably because of mutations in primers, and were replaced. These SNPs permitted to identify patterns of isolation-by-distance for some rivers. Finally, we found that microsatellite and SNP markers yielded very similar patterns for population differentiation and admixture assessments, with SNPs having better ability to detect introgression and differentiation