Distribución e hibridación de dos gobios sedentarios (Pomatoschistus microps y Pomatoschistus marmoratus) en las lagunas del sur de Francia

Pomatoschistus marmoratus and Pomatoschistus microps are small sedentary gobies inhabiting the lagoons of European Mediterranean and Atlantic coasts. Along the French Mediterranean coast their respective geographical distribution is not precisely known, in part because they are cryptic species. In this study, 512 gobies of both species were caught as 17 samples in 12 lagoons of the Gulf of Lion on the French Mediterranean coast. They were genotyped at six microsatellite loci and investigated statistically using multidimensional analyses, Bayesian assignment (Structure) and NewHybrids classification. This allowed the contrasted distribution of each species (P. microps in the east, P. marmoratus in the west) to be described, with several exceptions. Neither geographic structure nor isolation by distance was detected among differentiated populations of each species. The suggested mechanism is a deep sedentary behaviour associated with foundations following extinctions. The two species are sympatric or even in syntopy in five or six sampled lagoons producing rare fertile hybrids.Pomatoschistus marmoratus y Pomatoschistus microps son pequeños gobios sedentarios que habitan las lagunas de las costas mediterráneas y atlánticas. Sus distribuciones geográficas respectivas no se conocen con precisión a lo largo de las costas mediterráneas francesas, en parte porque son especies crípticas. En este estudio, se capturaron 512 gobios de ambas especies en 17 muestras de 12 lagunas del Golfo de León, en la costa mediterránea francesa. Han sido genotipados en seis loci de microsatélites e investigados estadísticamente con análisis multidimensionales, asignación bayesiana (Structure) y clasificación de NewHybrids. Esto permitió describir la distribución contrastada de cada especie (P. microps en el este, P. marmoratus en el oeste), con varias excepciones. Ni la estructura geográfica ni el aislamiento por la distancia se detectaron entre poblaciones diferenciadas de cada especie. El mecanismo sugerido es un comportamiento sedentario fuerte asociado con las migraciones posteriores a las extinciones. Las dos especies son simpátricas o incluso en syntopia en 5 o 6 lagunas muestreadas y producen raros híbridos fértiles

DISTRIBUTION OF TROPICAL EEL GENUS Anguilla IN INDONESIA WATER BASED ON SEMI-MULTIPLEX PCR

Tropical eels living in Indonesian waters are known to be composed of several species, but their real listing together with their distribution ranges need to be established. The main difficulties are the very high number of islands with perennial rivers where these species are living during the growth phase of their life cycle. It is difficult, sometimes impossible, to determine the species using morphological characters, moreover on glass eels. In order to establish the geographic distribution of tropical eels of the genus Anguilla in Indonesian waters, a total 1,115 specimens were collected between 2008 and 2012. Sample collection was done in the growth habitats that are rivers and estuaries by commercial nets of different categories according to the fish size. All samples were identified genetically using the recently developed semimultiplex PCR method. We recognized four species and subspecies with wide distribution: Anguilla bicolor bicolor, Anguilla bicolor pacifica, Anguilla marmorata, and Anguilla interioris; two species with limited distribution, close to endemism: Anguilla celebesensis and Anguilla borneensis and one subspecies Anguilla nebulosa nebulosa that is only spread in river flowing into Indian Ocean

Evidence of unidirectional gene flow in a fragmented population of Salmo trutta L

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La osmoregulación como factor potencial de la distribución diferencial de dos especies crípticas de góbido, Pomatoschistus microps y P. marmoratus, en las lagunas mediterráneas francesas

This study was aimed at the detection of potential differences in the osmoregulatory capacity of two cryptic species of gobies, Pomatoschistus microps (Krøyer, 1838) and P. marmoratus (Risso, 1810), that have different distributions in French Mediterranean lagoons characterised by different salinity regimes. Specimens of both species were experimentally exposed to different salinities, their salinity tolerance was evaluated and their blood osmolality was measured. Both species are strong osmoregulators over a wide range of salinities but P. microps showed higher performances of hyper-regulation at very low salinities (10 and 40 mosm/kg, i.e. freshwater 0.3 and 1.4) and of hypo-regulation at high salinities (1500 mosm/kg, 51). Only P. microps was able to tolerate freshwater exposure over 4 days. We conclude that the high osmoregulatory capacity found in P. microps is linked to its better survival at very low salinities and is a physiological requirement for living in areas such as the Mauguio lagoon where salinity is highly variable. In contrast, as osmoregulation of P. marmoratus is less efficient at extreme salinities, this species cannot colonise such environments and is restricted to habitats where salinity is more stable, such as the Thau lagoon.Este estudio tuvo por objeto la detección de diferencias potenciales en la capacidad osmorreguladora de dos especies crípticas de góbido, Pomatoschistus microps (Krøyer, 1838) y P. marmoratus (Risso, 1810), que presentan diferentes áreas de distribución en lagunas mediterráneas francesas caracterizadas por regímenes de salinidad distintos. Especímenes de ambas especies fueron expuestos experimentalmente a diferentes salinidades, evaluándose su tolerancia a la salinidad y midiéndose su osmolalidad sanguínea. Ambas especies tienen una amplia capacidad osmoreguladora en un amplio rango de salinidades. Sin embargo, en comparación con P. marmoratus, P. microps mostró mayores rendimientos hiper-regulatorios a salinidades muy bajas (10 y 40 mosm/kg, es decir agua dulce 0.3 y 1.4) e hipo-regulatorios a salinidades altas (1500 mosm/kg, 51). Sólo P. microps fue capaz de tolerar la exposición al agua dulce durante 4 días. Podemos concluir que la gran capacidad osmoreguladora encontrada en P. microps está ligada a su mayor supervivencia a salinidades muy bajas, siendo un requerimiento fisiológico para vivir en áreas tales como la laguna de Mauguio, donde la salinidad es muy variable. Por el contrario, puesto que la osmoregulación de P. marmoratus es menos eficiente en salinidades extremas, esta especie no puede colonizar tales ambientes y se ve restringida a hábitats donde la salinidad es más estable, como la laguna de Tha

Nuclear Markers of Danube Sturgeons Hybridization

Acipenseriformes are composed of 25 sturgeon species and two paddlefish species distributed exclusively in the northern hemisphere. The Danube River and the Black Sea were originally inhabited by six sturgeon species but two are extinct and only four are still reproducing currently in the Lower Danube: Huso huso, Acipenser stellatus, A. gueldenstaedtii and A. ruthenus. Sturgeon species hybridize more easily than other fish and the determination of pure species or hybrid status is important for conservation and for breeding in fish farms. This survey demonstrated that morphological determination of this status is not reliable and a molecular tool, based on eight microsatellites genotypes is proposed. This method, based on three successive statistical analyses including Factorial Correspondence Analysis (FCA), Structure assignation and NewHybrids status determination, showed a high efficiency in discriminating pure species specimens from F1, F2 and two kinds of backcross individuals involving three of the four reproducing Lower Danube sturgeon species

La Génétique des Truites et son Application au Cas de la Corse

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Les Premières Descriptions de Truite et l'Etat des Connaissances avant le LIFE

La compréhension de l'organisation des nombreuses truites européennes et leur protection nécessitent d'utiliser des outils de description plus fiables que la morphologie qui se résume souvent, à quelques exceptions près, à la description de leur robe (Delling & Doadrio 2005; Susnik et al. 2007). La robe des truites est une donnée extrèmement changeante qui n'a pas toujours de valeur fondamentale. Ainsi, Lascaux (1996) démontre que dans les Pyrénées-Orientales, la robe des truites est une combinaison de points noirs surtout commandés par la génétique et de points rouges surtout commandés par les conditions écologiques du milieu, donc peu héritables

Genetic structure of brown trout (Salmo trutta, L.) populations from south-western France: data from mitochondrial control region variability

International audienceThe genetic relationships between several French Atlantic populations of brown trout were analysed using polymerase chain reaction–single-strand conformation polymorphism and sequencing of two parts of the mitochondrial control region. Ten mitochondrial haplotypes were identified, separated by a small number of mutations. The distribution of these haplotypes confirmed our hypothesis of the existence of two genetically well-differentiated groups of populations in this area, which has already been suggested using nuclear markers. Nuclear and mitochondrial markers, however, show different patterns of genetic differentiation: some populations which belong to one group according to allozyme results appear to be part of the other when using mitochondrial DNA. The origin of these different forms is discussed; they seem to belong to the Atlantic grouping. Nevertheless, the hypothesis of an ancestral and a modern form suggested for northern populations does not appear valid in this particular case