juha-pekka.vaha@utu.fi |
Journal articles | |
2007 |
J -P Vähä, J Erkinaro, E Niemelä, C R Primmer (2007) Life-history and habitat features influence the within-river genetic structure of Atlantic salmon Molecular Ecology 16: 2638-2654 Abstract: Defining populations and identifying ecological and life-history characteristics affecting
genetic structure is important for understanding species biology and hence, for managing
threatened or endangered species or populations. In this study, populations of the world’s
largest indigenous Atlantic salmon (
Salmo salar
) stock were first inferred using model-based
clustering methods, following which life-history and habitat variables best predicting the
genetic diversity of populations were identified. This study revealed that natal homing
of Atlantic salmon within the Teno River system is accurate at least to the tributary level.
Generally, defining populations by main tributaries was observed to be a reasonable approach
in this large river system, whereas in the mainstem of the river, the number of inferred populations
was fewer than the number of distinct sampling sites. Mainstem and headwater
populations were genetically more diverse and less diverged, while each tributary fostered
a distinct population with high genetic differentiation and lower genetic diversity. Population
structure and variation in genetic diversity among populations were poorly explained
by geographical distance. In contrast, age-structure, as estimated by the proportion of
multisea-winter spawners, was the most predictive variable in explaining the variation in the
genetic diversity of the populations. This observation, being in agreement with theoretical
predictions, emphasizes the essence of large multisea-winter females in maintaining the
genetic diversity of populations. In addition, the unique genetic diversity of populations,
as estimated by private allele richness, was affected by the ease of accessibility of a site,
with more difficult to access sites having lower unique genetic diversity. Our results show
that despite this species’ high capacity for migration, tributaries foster relatively closed
populations with little gene flow which will be important to consider when developing
management strategies for the system. Notes:
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