Ecological determinants and temporal stability of the within-river population structure in Atlantic salmon (Salmo salar L.) *

2000 ◽  
Vol 9 (5) ◽  
pp. 615-628 ◽  
Author(s):  
Dany Garant ◽  
Julian J. Dodson ◽  
Louis Bernatchez
Keyword(s):  
Population Structure ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Temporal Stability ◽  
River Population ◽  
Atlantic Salmon Salmo Salar

A temporal perspective on population structure and gene flow in Atlantic salmon (Salmo salar) in Newfoundland, Canada

2010 ◽  
Vol 67 (2) ◽  
pp. 225-242 ◽  
Author(s):  
Friso P. Palstra ◽  
Daniel E. Ruzzante
Keyword(s):  
Population Dynamics ◽  
Population Structure ◽  
Gene Flow ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Environmental Changes ◽  
Population Connectivity ◽  
Temporal Perspective ◽  
Atlantic Salmon Salmo Salar ◽  
Contemporary Gene Flow

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.

Temporal Variation of Meristic Traits within an Atlantic Salmon (Salmo salar) Stock, and Implications for Stock Identification

1988 ◽  
Vol 45 (8) ◽  
pp. 1330-1339 ◽  
Author(s):  
D. M. Blouw ◽  
S. D. Saxon ◽  
E. M. P. Chadwick
Keyword(s):  
Atlantic Salmon ◽  
Temporal Variation ◽  
Salmo Salar ◽  
Null Hypothesis ◽  
Temporal Stability ◽  
River System ◽  
Stock Identification ◽  
Atlantic Salmon Salmo Salar ◽  
Group Variation ◽  
Made In

The assumption is generally made in stock identification studies that variation within stocks is not confounded with variation among them. To evaluate whether this assumption is tenable we test the null hypothesis of temporal stability in five key meristic traits of a single stock of Atlantic salmon (Salmo salar). We used smolts collected over a 10-yr period in the downstream migrations from one small river system. Individuals were tagged when captured and preserved, so we can estimate variability within, as well as among, runs. The meristic traits are remarkably homogenous within runs and cohorts. However, the null hypothesis of stability over time among runs and cohorts is strongly rejected for each trait. We conclude that temporal variation is both extensive and persistent. There is limited covariation among the traits, but they are largely independent of scores of environmental variables and of variation in the biological attributes of the stock. Because among-group variability is meaningful only in context of within-group variation, and because the within-group variation is large, our results have serious implications for sampling design in stock identification studies.

Retrospective growth analysis of Atlantic salmon (Salmo salar) from the Miramichi River, Canada

2009 ◽  
Vol 66 (8) ◽  
pp. 1294-1308 ◽  
Author(s):  
Kevin D. Friedland ◽  
David Moore ◽  
Fiona Hogan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Negative Correlation ◽  
Age Groups ◽  
Growth Conditions ◽  
River Population ◽  
Zone Length ◽  
Atlantic Salmon Salmo Salar ◽  
Predation Mortality ◽  
Freshwater Zone

We have developed a multidecadal retrospective growth history for the principal sea-age groups of the Miramichi River population of Atlantic salmon ( Salmo salar ) that characterizes freshwater growth and marine growth partitioned on a number of different time scales. Based on precedent with European salmon, we tested whether postsmolt growth was positively correlated with recruitment, assuming that growth during the postsmolt year mediates predation mortality. We found no such correlation in the Miramichi postsmolt growth pattern and instead found evidence of a negative correlation between growth and recruitment established by the second month that the fish were at sea. This negative correlation was interpreted as a density-dependant response of the population to recruitment determined early in the marine phase. There was inconsistent evidence that smolt size, as represented by freshwater zone length of the scale, influenced the pattern of recruitment. Finally, we found systematic differences between one-sea-winter (1SW) and 2SW returns related to greater postsmolt growth and, in particular, greater winter growth experienced by fish maturing after the first sea-winter. These data are consistent with findings relating climate variability during the months after smolts migrate to sea and recruitment variability, suggesting that the mortality is a short-duration event independent of growth conditions.

scholarly journals Managing Atlantic salmon (Salmo salar L.) in the mixed stock environment: challenges and considerations

2004 ◽  
Vol 61 (8) ◽  
pp. 1344-1358 ◽  
Author(s):  
W.W. Crozier ◽  
P-J. Schön ◽  
G. Chaput ◽  
E.C.E. Potter ◽  
N.Ó Maoiléidigh ◽  
...  
Keyword(s):  
Population Structure ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar ◽  
Mixed Stock ◽  
Made In

Abstract Atlantic salmon, as a result of their population structure and behaviour, are potentially subject to a complex array of fisheries, ranging from those within rivers harvesting single stocks, to distant-water mixed stock fisheries that harvest fish from different countries, stock complexes, and continents. In addition, estuarine and in-river fisheries may catch fish from more than one stock or stock component, where these are present. One of the main challenges in managing salmon across this range of fisheries is to account for the differing status of stocks with respect to safe biological limits, noting that stocks of differing productivity may require different harvest strategies. Also, the existence of sequential harvest in different fisheries provides unique challenges, because decisions in an individual fishery cannot be made in isolation of the impacts of other fisheries on those stocks. We illustrate the uncertainties and complexities involved in managing mixed stocks of salmon, whether in home-waters or in distant-water fisheries, and examples are given to illustrate how science and management are, or should be, developing to face these challenges.

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