Reproductive Strategies Explain Genetic Diversity in Atlantic Salmon, Salmo salar

Valiente, America G.; Juanes, Francis; García‐Vázquez, Eva

doi:10.1007/s10641-005-1331-8

Cited by 27 publications

(36 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a Pacific salmon hatchery programme, Waples & Do (1994) demonstrated that broodstock practices such as sib-avoidance mating had little permanent effect on the level of inbreeding. This hypothesis is supported by the high levels of heterozygosity we found which is consistent with other small endangered populations at this latitude (Perez et al 1997;Moran & Garcia-Vazquez 1998;Martinez et al 2000;Valiente et al 2005). As the older breeding cohorts are composed mostly of females and the younger (adults, mature parr) mostly of males, high heterozygosities can be explained, at least partially, on the basis of this outbred mating between different cohorts.…”

Section: Discussionsupporting

confidence: 90%

Reproductive strategies in small populations: using Atlantic salmon as a case study

Juanes

Pérez

García‐Vázquez

2007

Ecology of Freshwater Fish

View full text Add to dashboard Cite

Wild salmonid populations with only a few breeding adults may not exhibit a significant reduction in genetic variability compared with larger populations. Such an observation suggests that effective population sizes are larger than population size estimates based on direct adult counts and/or the mating strategy maximises outbreeding, contributing to increased heterozygosity. In the case of wild Atlantic salmon Salmo salar populations, stratification by age classes and sexes on the spawning grounds avoids inbreeding and increases genetic variability. We studied the breeding composition of four Spanish salmon populations. Over a 7-year period we concluded that the probability of within-cohort mating is very low: females generally reproduce after two sea-winters whereas males reproduce mostly as one sea-winter (grilse) and/or mature parr. Considering different levels of contribution of mature parr to spawning derived from field surveys, we developed a simple model for estimating effective population sizes and found that they doubled with 65% parr contribution expected for rivers at this latitude (43°N), and ranged from 100-800 individuals. The effect of between-cohort mating was modelled considering different ranges of differences in allele frequencies between cohorts and resulted in 28-50% increases in heterozygosity when considering a 65% parr contribution. The complex mating strategy of Atlantic salmon contributes to explain the high levels of genetic variability found for small populations of this species. This model can probably be extended to other animal species with mating strategies involving different cohorts.

show abstract

Section: Discussionsupporting

confidence: 90%

Reproductive strategies in small populations: using Atlantic salmon as a case study

Juanes

Pérez

García‐Vázquez

2007

Ecology of Freshwater Fish

View full text Add to dashboard Cite

show abstract

“…Mature male parr reproduction has been speculated to be beneficial for N e (Saunders and Schom 1985;L'Abée-Lund 1989;Martinez et al 2000;Valiente et al 2005;Juanes et al 2007), although mature parr may ''increase'' effective size only in the sense thatN e is increased compared to when mature parr are ignored in analyses (e.g., Jones and Hutchings 2002;Saura et al 2008). Nevertheless, the reasoning implies that parr reproductive contribution increases N e by reducing the variance in (male) individual reproductive success.…”

Section: Discussionmentioning

confidence: 99%

Age Structure, Changing Demography and Effective Population Size in Atlantic Salmon (Salmo salar)

2009

View full text Add to dashboard Cite

Effective population size (N e ) is a central evolutionary concept, but its genetic estimation can be significantly complicated by age structure. Here we investigate N e in Atlantic salmon (Salmo salar) populations that have undergone changes in demography and population dynamics, applying four different genetic estimators. For this purpose we use genetic data (14 microsatellite markers) from archived scale samples collected between 1951 and 2004. Through life table simulations we assess the genetic consequences of life history variation on N e . Although variation in reproductive contribution by mature parr affects age structure, we find that its effect on N e estimation may be relatively minor. A comparison of estimator models suggests that even low iteroparity may upwardly bias N e estimates when ignored (semelparity assumed) and should thus empirically be accounted for. Our results indicate that N e may have changed over time in relatively small populations, but otherwise remained stable. Our ability to detect changes in N e in larger populations was, however, likely hindered by sampling limitations. An evaluation of N e estimates in a demographic context suggests that life history diversity, density-dependent factors, and metapopulation dynamics may all affect the genetic stability of these populations.

show abstract

“…Our homing and oceanography scenarios represent opposite extremes of the possible range of behaviours, which in reality are not necessarily mutually exclusive. In the homing scenario, fish were assumed to navigate back to their natal spawning ground from wherever they may have settled and grown up as juveniles, in much the same way as Atlantic salmon return from the ocean to their natal river or even tributary to spawn (Valiente et al, 2005;Verspoor et al, 2002). There was no such navigation behaviour in the oceanography scenario, and newly matured fish simply spawned in the area local to where they had spent their juvenile years.…”

Section: Key Factors Affecting Population Structure and Dynamics Andmentioning

confidence: 99%

A model of meta-population dynamics for North Sea and West of Scotland cod—The dynamic consequences of natal fidelity

et al. 2008

View full text Add to dashboard Cite

It is clear from a variety of data that cod (Gadus morhua) in the North Sea do not constitute a homogeneous population that will rapidly redistribute in response to local variability in exploitation. Hence, local exploitation has the potential to deplete local populations, perhaps to the extent that depensation occurs and recovery is impossible without recolonisation from other areas, with consequent loss of genetic diversity. The oceanographic, biological and behavioural processes which maintain the spatial population structures are only partly understood, and one of the key unknown factors is the extent to which cod exhibit homing migrations to natal spawning areas. Here, we describe a model comprising 10 interlinked demes of cod in European waters, each representing groups of fish with a common natal origin. The spawning locations of fish in each deme are governed by a variety of rules concerning oceanographic dispersal, migration behaviour and straying. We describe numerical experiments with the model and comparisons with observations, which lead us to conclude that active homing is probably not necessary to explain some of the population structures of European cod. Separation of some sub-populations is possible through distance and oceanographic processes affecting the dispersal of eggs and larvae. However, other evidence suggests that homing may be a necessary behaviour to explain the structure of other sub-populations. The consequences for fisheries management of taking into account spatial population structuring are complicated. For example, recovery or recolonisation strategies require consideration not only of mortality rates in the target area for restoration, but also in the source areas for the recruits which may be far removed depending on the oceanography. The model has an inbuilt capability to address issues concerning the effects of climate change, including temperature change, on spatial patterns of recruitment, development and population structure in cod.

show abstract

Reproductive Strategies Explain Genetic Diversity in Atlantic Salmon, Salmo salar

Cited by 27 publications

References 68 publications

Reproductive strategies in small populations: using Atlantic salmon as a case study

Reproductive strategies in small populations: using Atlantic salmon as a case study

Age Structure, Changing Demography and Effective Population Size in Atlantic Salmon (Salmo salar)

A model of meta-population dynamics for North Sea and West of Scotland cod—The dynamic consequences of natal fidelity

Contact Info

Product

Resources

About