Genetic structure of Atlantic salmon populations in France
This thesis investigates the genetic structure among Atlantic salmon populations from France. We more specifically studied the influence of environmental factors and stocking on the spatial distribution of genetic diversity. We genotyped at 17 microsatellite markers 1739 individuals from 34 French r...
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| Other Authors: | , , , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | French |
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HAL CCSD
2010
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| Subjects: | |
| Online Access: | https://hal.inrae.fr/tel-02921531 https://hal.inrae.fr/tel-02921531/document https://hal.inrae.fr/tel-02921531/file/0R7-Thesis.PHD.Perrier2010.pdf |
| Summary: | This thesis investigates the genetic structure among Atlantic salmon populations from France. We more specifically studied the influence of environmental factors and stocking on the spatial distribution of genetic diversity. We genotyped at 17 microsatellite markers 1739 individuals from 34 French rivers, from old (1965-1987) and recent (1998-2006) cohorts. Analyses of recent samples classed individuals into five genetically and geographically distinct groups. Distance among estuaries and river length were strong predictors of population structure. Moreover, the positive trend between body size and river length and the higher differentiation of the population having farthest spawning grounds off the river mouth suggest local adaptation to upstream migration difficulty. Comparison of recent and old samples showed a general reduction of differentiation among populations and some high introgression rates most probably resulting from stocking. In some depopulated rivers were no stocking was performed we observed natural recolonization by fish from neighbouring and distant stocks. To quantify the impact of stocking on some populations for which it was precisely documented, we developed an approach using temporally explicit simulations. This study suggests low fitness of stocking fish. In parallel to genetic analyses, we carried on microchemistry analyses of otolith from some fish from stocked populations. Coupling genetic and microchemistry analyses on the same individuals allowed identifying river-born fish with hatchery pedigrees, discriminating them from hatchery-born fish with same genetic characteristics. Cette thèse porte sur la structuration génétique des populations françaises de saumon Atlantique. Nous avons notamment étudié l’effet de facteurs environnementaux et des repeuplements sur la distribution spatiale de la diversité génétique. 1739 individus échantillonnés dans 34 rivières et provenant de cohortes anciennes (1965-1987) et récentes (1998-2006) ont été génotypés à 17 marqueurs microsatellites. Les ... |
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