Phylogeography and historical introgression in smoothtail nine-spined sticklebacks, Pungitius laevis (Gasterosteiformes : Gasterosteidae)

Pleistocene glaciations have strongly affected the biogeography of many species residing in periglacial and previously glaciated regions. Smoothtail nine-spined sticklebacks (Pungitius laevis) have three highly divergent mitochondrial lineages in France, one of which shares the same mitochondrial cluster with a congener P. pungitius. To understand if interspecific introgression has happened between the two species, we carried out phylogeographic and population genetic analyses using mitochondrial and nuclear gene sequences. Our results indicated asymmetric mitochondrial introgression from P. pungitius to P. laevis and genetic admixture of these species in one of the P. laevis lineages, suggesting historical hybridization. Deep intraspecific mitochondrial divergence within P. laevis in central and southern France mostly coinciding with major drainages suggests that these areas were important glacial refugia for the species explaining the observed intraspecific divergence. The historical hybridization between P. laevis and P. pungitius likely occurred in a refugium at central France, and the newly formed P. laevis lineage spread northward during postglacial recolonization. The study adds to the long list of species showing complete mitogenome capture owing to historical hybridizations, and highlights the reticulate nature of population differentiation in taxa subject to postglacial range-expansions.Peer reviewe

Etude pluridisciplinaire des populations de truite commune (Salmo trutta L.) des torrents haut-savoyards soumises à repeuplement (diversité intra-spécifique, évaluation de pratiques de gestion et ingénierie de la conservation de populations natives)

Le premier volet du présent travail décrit (microsatellites de l' ADN) la diversité génétique des populations de truite (Salmo trutta) sur l'ensemble du réseau hydrographique de la Haute-Savoie et des principaux stocks de pisciculture utilisés pour le repeuplement. L'analyse de 163 secteurs a permis de localiser onze zones abritant encore des populations natives d'origine méditerranéenne. L'étude de la structuration génétique de ces populations natives a conduit à déterminer six unités de gestion génétiquement différenciées devant être gérées comme des entités indépendantes. Le deuxième volet s'attache à décrire les pratiques de repeuplement et à évaluer en vraie grandeur et à large échelle spatiale la contribution du repeuplement et du recrutement naturel. Pour ce faire, le fluoromarquage des otolithes à l'alizarine redS a été développé pour marquer près de 3 millions d'alevins par an pendant trois ans. L'étude met en évidence une contribution dominante du recrutement naturel dans les populations en place comme dans les captures par pêche à la ligne. Les résultats montrent, sans pouvoir identifier les causes, une forte variation spatiale et temporelle de la contribution des repeuplements et ce y compris lorsque les pratiques ne changent pas. La troisième partie présente des suivis temporels visant à évaluer les effets génétiques de différentes stratégies de conservation et de réhabilitation de populations natives. Les résultats de ces suivis permettent d'apporter des éléments d'aides à la décision aux gestionnaires des populations confrontés à diverses situations.In the first part, the genetic diversity of wild brown trout (Salmo trutta) populations is described (by analysis of microsatelittes of the ADN) on the whole hydrographic network of the Haute-Savoie. The main hatchery strains used to stock the rivers were studied too. The analysis of 163 river sectors allowed the location of eleven zones still harbouring native populations of the mediterranean lineage. The genetic structuration of these native populations allowed to determine six different management units. The second part presents a description of the stocking practices and an assesment, at large scale, of the respective contribution of stocking and natural recruitment. For that, the otolith fluoromarking method with Alizarin RedS was used to mark about 3 millions of fry by year during three years. The study has shown a higher contribution of the natural recruitment than stocking in standing population and in catches by anglers. The result showed, without knowing the reasons, high spatial and temporal variabilities of stocking contribution and that despite using the same restocking procedures. To finish, temporal studies were developped to evaluate the genetic effects of several strategies aimed to conserve and/or to rehabilite native populations. The results allow to help fishery managers to better conserve and restore native populations of brown trout.CHAMBERY -BU Bourget (730512101) / SudocSudocFranceF

Relative ages of present populations of

The biogeographic history of French freshwater fish is poorly defined, and fishery managers do not currently take into account the only functional level, that of genetic stocks. The aim of the present paper is to provide a contribution for filling this gap. It surveys existing knowledge and previous studies of the genus Barbus in France. A first part chronicles the populations of the two French species according to ancient (tertiary) and recent (pre- and post-glacial, and contemporary) history. Thus, the Barbus meridionalis lineage seems to have been present in this country for 5 million years at least (Upper Miocene), but the present populations of the Rhône Valley seem to be the result of recent recolonization by populations restricted to a Languedoc-Roussillon sanctuary during the glaciations. B. barbus has its origin in the Danube drainage basin. It is a more recent invader in Western Europe. Its immigration may have occurred during the Pliocene interconnections between the Rhône, the Rhine and the Danube basins (and perhaps even that of the Loire), or even more recently. If the first assumption is correct, the present populations of the Rhône are presumably descended from populations that found a shelter in the southern tributaries of the right bank of the river, or even in the tributaries of the right bank of the River Saône. In the Rhine basin, the sanctuary may have been the tributaries of the left bank, the Meuse and the Mosel Rivers, from which probably descend the populations of Eastern England. The present occurrence of B. barbus in the Garonne catchment and perhaps also the Seine catchment seems to be due to man. The second part of the paper considers the genetic point of view, but the lack of data make it possible to discuss only the status of B. meridionalis. A synthesis of the available enzymatic data, compared with the hypotheses expressed in the first part, reveals a good agreement between the two approaches. In particular, the French an Spanish populations are well differentiated from one another, confirming the ancient settlement of the species in these countries. Moreover, the homogeneity of the French populations, and the higher polymorphism of the Roussillon population, agree with the presumption of a survival in this province during the glaciations. For instance, the first results on B. barbus show a very low polymorphism and a very high homogeneity throughout the different catchments examined (Rhône, Meuse, Garonne, Hérault). Based on this work, a historical diagram is proposed, with the aim of ordinating the hypotheses for future research on the genetics of this group

Structuration génétique des populations de poissons d'eau vive (comparaison de l'influence respective de l'hydrographie et des traits biologiques chez l'ombre commun et le chabot)

En deçà du niveau taxonomique de l'espèce, la gestion du patrimoine piscicole dans une perspective de "conservation de la biodiversité" nécessite d'appréhender le fonctionnement de ses composantes populationnelles et évolutives en fonction des contraintes physiques inhérentes au réseau hydrographique et des réponses biologiques développées par les espèces, l'ensemble se traduisant directement en termes de structures génétiques et flux géniques. Ces relations ont été abordées par l'électrophorèse des protéines chez deux espèces d'eau vive aux stratégies biologiques contrastées, le chabot (Cottus gabio s.l.) et l'ombre commun (Thymallus thymallus). Le chabot présente de fréquentes fixations alléliques différentielles entre populations qui se traduisent par des distances de Nei intra bassin atteignant 0,22 dans un petit bassin comme celui de l'Hérault et de 0,43 dans celui de la Loire. Les distances inter bassins peuvent quant à elles dépasser 0,76. L'ombre commun, montre des distances près de deux fois moindres en inter bassin, et jusqu'à dix fois moindres en intra bassin (0,032 dans le bassin ligérien). À l'échelle du bassin, la variabilité intra population apparaît deux fois plus faible que la variabilité inter population chez le chabot (14,7% de la variabilité totale contre 30,1%), alors que la tendance inverse est observée chez l'ombre (37,4% contre 18%). Ces différences peuvent être reliées aux caractéristiques biologiques de ces espèces. Le chabot, beaucoup plus sédentaire et bien moins fécond, a une taille efficace de ses populations réduite d'autant, d'où une baisse de la diversité intra population et une divergence rapide des populations. En conséquence, alors que l'unité fonctionnelle et évolutive est de l'ordre du bassin hydrographique chez l'ombre commun, elle ne dépasse guère la rivière ou même le tronçon de rivière chez le chabot.LYON1-BU.Sciences (692662101) / SudocSudocFranceF

Genetic integrity of European grayling (Thymallus thymallus L. 1758) within the Vienne River drainage basin after five decades of stockings

European grayling of the upper Vienne River drainage basin represent the westernmost populations inside the natural distribution of the species. Since the 19th century, their extension across this sub-basin has been dramatically reduced by the harnessing of the river network for dams, initially serving mills but then hydroelectric power generation. Since the 1960s, local fishing authorities have attempted to compensate for these declines with stocking programs, but the efficiency of these efforts have never been accurately monitored. We aim to evaluate the genetic imprints of these stocking programs and thus provide an indirect measure of the long-term survival of stocked fish. Three target populations were analyzed at both mtDNA (Control Region) and nDNA levels (12 µSats), and compared to populations representative of surrounding drainage basins or fish farm facilities. Among 37 "wild" fish sequenced, only three control region haplotypes were identified, all belonging to the highly divergent Loire basin lineage. Two were specific to the Upper Vienne area, and one was observed in some individuals of the most downstream location, but previously described from the upper Allier sub-drainage. Microsatellite analysis of 87 "wild" fish also demonstrated a rather low diversity within each population (but typical for the Loire drainage) with all Upper Vienne individuals belonging to a single diagnosable unit. This genetic cluster was clearly distinct from all other samples including hatchery strains, which strongly supports its native origin. The only piece of evidence of a possible stocking contribution was the occurrence of the Allier haplotype, but it cannot be excluded that this haplotype was also native to this reach of river. The total lack of genetic impact of five decades of stocking deeply questions the efficacy of this management approach, at least in a regional context

Biogéographie et historique de la mise en place des peuplements ichtyologiques de France métropolitaine

International audienc

Premier signalement de Salaria fluviatilis dans le lac Léman

International audienceIn May 2010, a fishing campaign by electricity on three distant sites along the French side of the lake Geneva provided regular catches of freshwater blennies, Salaria fluviatilis (Asso, 1801). This is the first record of the species in this lake

La redécouverte de l'ichtyofaune d'eau douce de France métropolitaine

International audienc

A multidimensional typology of riverbank habitats explains the distribution of European grayling (Thymallus thymallusL.) fry in a temperate river

For species at risk, rehabilitation of riverbank habitats may be a promising way to sustain abundance of early‐life stages, provided that fish—habitat relationships are significant and the scale at which they are described is relevant to both fish ecology and management purposes. Here, habitat use of the threatened E uropean grayling (T hymallus thymallus ) fry was analysed in an alluvial F rench‐S wiss border river, the A llondon. Based on five descriptive variables, a practical typology of available bank habitats was first defined to categorise ecological conditions into five easily distinguishable habitat types (HT s). These represent marginal patches of multivariate homogeneous habitat from a few to tens of square metres [median area = 8 m−2; range (10%–90%) = 1.9–32.6 m−2]. Comparing the habitat used by fry to those available revealed a clear selection for two of the five HT s, that is, gravel bar shorelines (HT 4) and depositional beaches along pool margins (HT 3). Because of their multidimensional nature and larger spatial scale, HT s did not strictly reflect an up‐scaling of univariate selection patterns at the microhabitat scale. Results emphasised that the preservation of the alluvial dynamics of the river and bank patchiness are basic to E uropean grayling, and suggested that the patch scale may represent a good compromise between ecological relevancy and practical management needs. The herein developed typological approach may be transferred to other rivers and help conserve E uropean grayling populations by enhancing fry habitat suitability

A multidimensional typology of riverbank habitats explains the distribution of European grayling (Thymallus thymallus L.) fry in a temperate river

International audienceFor species at risk, rehabilitation of riverbank habitats may be a promising way to sustain abundance of early-life stages, provided that fish-habitat relationships are significant and the scale at which they are described is relevant to both fish ecology and management purposes. Here, habitat use of the threatened European grayling (Thymallus thymallus) fry was analysed in an alluvial French-Swiss border river, the Allondon. Based on five descriptive variables, a practical typology of available bank habitats was first defined to categorise ecological conditions into five easily distinguishable habitat types (HTs). These represent marginal patches of multivariate homogeneous habitat from a few to tens of square metres [median area = 8 m(-2); range (10%-90%) = 1.9-32.6 m(-2)]. Comparing the habitat used by fry to those available revealed a clear selection for two of the five HTs, that is, gravel bar shorelines (HT4) and depositional beaches along pool margins (HT3). Because of their multidimensional nature and larger spatial scale, HTs did not strictly reflect an up-scaling of univariate selection patterns at the microhabitat scale. Results emphasised that the preservation of the alluvial dynamics of the river and bank patchiness are basic to European grayling, and suggested that the patch scale may represent a good compromise between ecological relevancy and practical management needs. The herein developed typological approach may be transferred to other rivers and help conserve European grayling populations by enhancing fry habitat suitability