Morphological variation within juvenile Atlantic salmon, Salmo salar, and brown trout, Salmo trutta, around the Loch Lomond, Scotland
Atlantic salmon and brown trout are salmonid species that share many common features, including the ability to reproduce together and create hybrids. In order to assess more precisely the rate of hybridisation that is increasing in Scotland and to understand how these individuals are characterised,...
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| Other Authors: | , , |
| Format: | Master Thesis |
| Language: | English |
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HAL CCSD
2023
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| Online Access: | https://dumas.ccsd.cnrs.fr/dumas-04583003 https://dumas.ccsd.cnrs.fr/dumas-04583003/document https://dumas.ccsd.cnrs.fr/dumas-04583003/file/2023clermont009.pdf |
| Summary: | Atlantic salmon and brown trout are salmonid species that share many common features, including the ability to reproduce together and create hybrids. In order to assess more precisely the rate of hybridisation that is increasing in Scotland and to understand how these individuals are characterised, one step is to study the morphological variation within salmon and trout populations. These two species are known to possess intraspecific genetic and phenotypic differences. In this context, quantifying these differences would make it easier to recognise hybrids. This is what the present study has achieved. Within the Loch Lomond catchment, trout and salmon populations are varied. In this study, the objectives were to quantify the morphological variations within juvenile salmon and trout, between different populations, between the sexes and also to see the effect of environmental parameters on morphologies. Eight different sites were studied. At these sites, seven populations of brown trout (133 individuals) and three of Atlantic salmon (59 individuals) were collected by electrofishing. Using photos of each individual, a geometric, morphometric and then statistical analysis was carried out, with adipose fin sampling to determine sex, and a survey of basic environmental parameters to see the effect of habitat on morphology. The results of this study conclude that there is morphological variation in populations on a small scale; seven of the ten groups of salmon and trout populations are significantly different. These groups have varied morphologies that are reflected in the scores of the canonical variables of the geometric morphometric analysis. It would appear that for a site containing salmon and trout, the environment affects both species in the same way. There was no different effect of habitat on the species. Variations between females and males were not significant. Finally, statistical analysis of the environmental parameters showed that only temperature had a significant effect on the morphologies of the ... |
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