Impact of human-induced environmental changes on genetic structure and variability in Atlantic salmon,Salmo salar

Studying population structure and gene flow patterns on temporal scales facilitates an evaluation of the consequences of demographic, physical, and environmental changes on the stability and persistence of populations. Here, we examine temporal genetic variation within and among Atlantic salmon ( Salmo salar ) rivers in Newfoundland and Labrador, Canada, using samples collected over a period of six decades (1951–2004). Our objective was to evaluate temporal changes in population connectivity associated with the closure of a commercial marine fishery. Despite demographic instability, we find that population structure remained temporally stable over more than 50 years. However, age structure can affect results when not taken into consideration, particularly in populations of large effective size where genetic drift is not strong. Where weak signals of genetic differentiation did not complicate analyses, contemporary migration was often asymmetric, yet low, suggesting patterns of intermittent gene flow. Nevertheless, we find some links between changes in population dynamics and contemporary gene flow. These findings may therefore imply that management decisions impacting the contemporary population dynamics of individual Atlantic salmon rivers can also affect the genetic stability of this species as a whole.

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A framework for understanding Atlantic salmon (Salmo salar) life history

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/d98-007 ◽

1998 ◽

Vol 55 (S1) ◽

pp. 48-58 ◽

Cited By ~ 28

Author(s):

Elizabeth A Marschall ◽

Thomas P Quinn ◽

Derek A Roff ◽

Jeffrey A Hutchings ◽

Neil B Metcalfe ◽

...

Keyword(s):

Life History ◽

Atlantic Salmon ◽

Salmo Salar ◽

Life History Traits ◽

Environmental Changes ◽

Individual Life ◽

Atlantic Salmon Salmo Salar ◽

Large Size ◽

The Family ◽

Long Time

We took a hierarchical approach to understanding Atlantic salmon (Salmo salar) life history patterns by first comparing salmonids to other teleosts, next comparing Atlantic salmon to other salmonids, and finally, mapping correlations among individual life history traits within Atlantic salmon. The combination of anadromy, large eggs, nest construction and egg burial by females, and large size at maturity differentiates salmonids from most other teleosts. Within the family Salmonidae, there is considerable variation in all traits but Atlantic salmon are generally in the middle of the range. Within Atlantic salmon, we were able to map correlations among individual life history traits, but we found that we still lacked an understanding comprehensive and quantitative enough to allow us to predict how the entire life history should respond to environmental changes. Thus, we proposed several general courses of action: (i) use models to synthesize complex patterns and relationships, (ii) collect long time series of data in individual systems, and (iii) design experiments to assess phenotypic plasticity and how environmental influences differ from genetic effects and constraints.

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