Identification and conservation of remnant genetic resources of brown trout in relict populations from Western Mediterranean streams

• Published in: Hydrobiologia 2013-05, Vol.707 (1), p.29-45
• Main Authors: Vera, M., Garcia-Marin, J. L., Martinez, P., Araguas, R. M., Bouza, C.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Aspectes genètics; Biological and medical sciences; Biomedical and Life Sciences; Canvi mediambiental global; Climate change; Climate prediction; Ecology; Fish hatcheries; Fish populations; Fresh water ecosystems; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects; Genetic aspects; Genetic disorders; Genetic drift; Genetic resources; Genetics of eukaryotes. Biological and molecular evolution; Genotype & phenotype; Genètica de poblacions; Global climate; Global environmental change; Global warming; Habitats; Life Sciences; Mitochondrial DNA; Population genetics; Population genetics, reproduction patterns; Primary Research Paper; Rivers; Salmo trutta; Streams; Synecology; Trout; Truites (Peixos); Water flow; Wildlife conservation; Zoology
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-012-1402-8

Brown trout is a cold-adapted freshwater species with restricted distribution to headwater streams in rivers of the South European peninsulas, where populations are highly vulnerable because Mediterranean regions are highly sensitive to the global climatic warming. Moreover, these populations are endangered due to the introgressive hybridization with cultured stocks. Individuals from six remnant populations in Western Mediterranean rivers were sequenced for the complete mitochondrial DNA control region and genotyped for 11 nuclear markers. Three different brown trout lineages were present in the studied region. Significant genetic divergence was observed among locations and a strong effect of genetic drift was suggested. An important stocking impact (close to 25%) was detected in the zone. Significant correlations between mitochondrial-based rates of hatchery introgression and water flow variation suggested a higher impact of stocked females in unstable habitats. In spite of hatchery introgression, all populations remained highly differentiated, suggesting that native genetic resources are still abundant. However, climatic predictions indicated that suitable habitats for the species in these rivers will be reduced and hence trout populations are highly endangered and vulnerable. Thus, management policies should take into account these predictions to design upstream refuge areas to protect remnant native trout in the region.