The study of molecular variation in Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.)

dc.check.embargoformatE-thesis on CORA onlyen
dc.check.reasonThis thesis is due for publication or the author is actively seeking to publish this materialen
dc.contributor.advisorCross, Thomas F.en
dc.contributor.advisorMcGinnity, Philipen
dc.contributor.authorO'Toole, Ciar
dc.contributor.funderDepartment of Agriculture, Food and the Marine, Irelanden
dc.description.abstractPolymorphic microsatellite DNA loci were used here in three studies, one on Salmo salar and two on S. trutta. In the case of S. salar, the survival of native fish and non-natives from a nearby catchment, and their hybrids, were compared in a freshwater common garden experiment and subsequently in ocean ranching, with parental assignment utilising microsatellites. Overall survival of non-natives was 35% of natives. This differential survival was mainly in the oceanic phase. These results imply a genetic basis and suggest local adaptation can occur in salmonids across relatively small geographic distances which may have important implications for the management of salmon populations. In the first case study with S trutta, the species was investigated throughout its spread as an invasive in Newfoundland, eastern Canada. Genetic investigation confirmed historical records that the majority of introductions were from a Scottish hatchery and provided a clear example of the structure of two expanding waves of spread along coasts, probably by natural straying of anadromous individuals, to the north and south of the point of human introduction. This study showed a clearer example of the genetic anatomy of an invasion than in previous studies with brown trout, and may have implications for the management of invasive species in general. Finally, the genetics of anadromous S. trutta from the Waterville catchment in south western Ireland were studied. Two significantly different population groupings, from tributaries in geographically distinct locations entering the largest lake in the catchment, were identified. These results were then used to assign very large rod caught sea trout individuals (so called “specimen” sea trout) back to region of origin, in a Genetic Stock Identification exercise. This suggested that the majority of these large sea trout originated from one of the two tributary groups. These results are relevant for the understanding of sea trout population dynamics and for the future management of this and other sea trout producing catchments. This thesis has demonstrated new insights into the population structuring of salmonids both between and within catchments. While these chapters look at the existence and scale of genetic variation from different angles, it might be concluded that the overarching message from this thesis should be to highlight the importance of maintaining genetic diversity in salmonid populations as vital for their long-term productivity and resilience.en
dc.description.sponsorshipDepartment of Agriculture, Food and the Marine, Ireland (Beaufort Maritime Research Awards Fish Population Genetics)en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.identifier.citationO'Toole, Ciar. 2014. The study of molecular variation in Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.). PhD Thesis, University College Cork.en
dc.publisherUniversity College Corken
dc.rights© 2014, Ciar O'Toole.en
dc.subjectAtlantic salmonen
dc.subjectSalmo salaren
dc.subjectSalmo truttaen
dc.subjectPopulation geneticsen
dc.subjectBrown trouten
dc.subjectMolecular variationen
dc.titleThe study of molecular variation in Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.)en
dc.typeDoctoral thesisen
dc.type.qualificationnamePhD (Science)en
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