The harbour porpoise and the grey seal in Iroise sea and along french atlantic coasts : population genetic and ecosystem modifications

• Main Author: Alfonsi, Eric
• Other Authors: Brest, Paulet, Yves-Marie, Jung, Jean-Luc
• Format: Thesis
• Language: French
• Published: 2013
• Subjects: Biodiversité génétique; Variations environnementales; Suivi systématique; Marqueurs mitochondriaux; Microsatellites; Phocoena phocoena; Halichoerus grypus; Genetic biodiversity; Environmental variations; Systematic monitoring; Mitochondrial markers; envir; anthro-se; Celtic Shelf; Retour; Harbour porpoise
• Online Access: http://www.theses.fr/2013BRES0073/document

Marine mammals are key species of ecosystems. They undergo numerous environment modifications which require conservation plans. For that, the knowledge about population structure is primary. Studies of population genetic were led about two flagship species of the Iroise Sea. For the harbour porpoise, a specie who know a return along french coasts, our works unexpectedly show this return is the result of two movements and an hybridization between individuals of the Iberia population and those of North Europe population. These movements are, probably, linked to modifications of prey's availability caused by environment changes. For the grey seal, our works show a great genetic richness, with an ancestral structure for the mitochondrial control region and a panmixia for the microsatellites loci, which are signs of a population at the scale of Celtic Shelf. A differentiation was observed between the stranding years even and odd and a possible genetic signal of individuals from another population. Finally we led a pilot study for marine mammal genetic biodiversity observatory with the DNA barcoding technique. This study shows this observatory may be a relevant and innovative means to follow the marine mammal biology. All our results bring new information about ecosystem variations and are a help for the establishment of conservation strategy. Les mammifères marins sont des espèces clés des écosystèmes. Ils subissent un nombre important de modifications de leur milieu qui nécessitent la mise en place de stratégie de conservation. Pour cela la connaissance de la structure des populations est primordiale. Une étude de génétique des populations a été menée sur deux espèces emblématiques de la mer d'Iroise. Pour le marsouin commun, espèce connaissant un retour le long des côtes françaises, nos travaux montrent, de manière inattendue, que ce retour est le résultat de deux déplacements différents et qu'il y a une hybridation entre les individus issus de la population de la péninsule Ibérique et ceux du Nord de l'Europe. ...