Genetic Diversity Patterns of Chum Salmon in the Pacific Northwest

Phelps, Stevan R.; LeClair, Larry L.; Young, Sewall F.; Blankenship, H. Lee

doi:10.1139/f94-296

Cited by 46 publications

(50 citation statements)

References 25 publications

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“…Results of our genetic analyses are consistent with other allozyme studies of Pacific salmon (e.g., Utter et al 1989;Phelps et al 1994) in finding quantitative (frequency) rather than qualitative (fixed) genetic differences among populations. Nevertheless, moderate genetic differentiation is evident over the geographic area covered, as indicated by the G ST -value for the overall dataset (0.138).…”

Section: Genetic Analysessupporting

confidence: 91%

Life-History Divergence in Chinook Salmon: Historic Contingency and Parallel Evolution

et al. 2004

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Abstract. By jointly considering patterns of genetic and life-history diversity in over 100 populations of Chinook salmon from California to British Columbia, we demonstrate the importance of two different mechanisms for lifehistory evolution. Mapping adult run timing (the life-history trait most commonly used to characterize salmon populations) onto a tree based on the genetic data shows that the same run-time phenotypes exist in many different genetic lineages. In a hierarchical gene diversity analysis, differences among major geographic and ecological provinces explained the majority (62%) of the overall G ST , whereas run-time differences explained only 10%. Collectively, these results indicate that run-timing diversity has developed independently by a process of parallel evolution in many different coastal areas. However, genetic differences between coastal populations with different run timing from the same basin are very modest (G ST Ͻ 0.02), indicating that evolutionary divergence of this trait linked to reproductive isolation has not led to parallel speciation, probably because of ongoing gene flow. A strikingly different pattern is seen in the interior Columbia River Basin, where run timing and other correlated life-history traits map cleanly onto two divergent genetic lineages (G ST ϳ 0.15), indicating that some patterns of life-history diversity have a much older origin. Indeed, genetic data indicate that in the interior Columbia Basin, the two divergent lineages behave essentially as separate biological species, showing little evidence of genetic contact in spite of the fact that they comigrate through large areas of the river and ocean and in some locations spawn in nearly adjacent areas.Key words. Allozymes, gene diversity analysis, life-history evolution, Pacific salmon, parallel speciation, run timing. The question of how rapidly and by what mechanisms adaptive differences arise among populations is of central interest to both evolutionary biologists and conservation biologists. Evidence is accumulating that evolution can occur at a rate high enough to be amenable to experimental observation within the lifetime of humans (Thompson 1998;Hendry and Kinnison 1999;Reznick and Ghalambor 2001). In addition, a number of recent studies have demonstrated the importance of parallel evolution, or repeated evolution of ecologically equivalent traits within a taxon (Reznick et al. 1996;Pigeon et al. 1997;Rundle et al. 2000;Johannesson 2001;Johnson 2001). Both types of studies raise questions about the importance of conserving existing life-history diversity and the likelihood that traits, once lost, will evolve once again-questions that are increasingly relevant to understanding the consequences of current rates of decline in biodiversity (Bernatchez 1995;Pimm and Raven 2000;Myers and Knoll 2001).Understanding the evolution of life-history diversity in salmon is particularly challenging, both because of the enormous complexity in life-history traits expressed by these species (Groot and Margolis 1991;Waples ...

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Section: Genetic Analysessupporting

confidence: 91%

Life-History Divergence in Chinook Salmon: Historic Contingency and Parallel Evolution

et al. 2004

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“…Studies that used numerous allozyme loci as well as those that included samples from a wide geographic area were chosen. The data sets included two studies on Chinook salmon (O. tshawytshca Walbaum- Bartley et al 1992;Waples et al 2004), two on chum salmon (O. keta Walbaum- Phelps et al 1994;Wilmot et al 1994) and two on sockeye salmon (O. nerka Walbaum- Varnavskaya et al 1994;Wood et al 1994) (Table 1). Allozyme alleles frequencies were taken directly from the publications.…”

Section: Methodsmentioning

confidence: 99%

“…The Phelps et al (1994) chum salmon dataset showed two loci as being significantly high F ST outliers (sAAT-3 and mIDHP-1: Fig. 3A).…”

Section: Chum Salmonmentioning

confidence: 99%

Analysis of F ST outliers at allozyme loci in Pacific salmon: implications for natural selection

Aguilar

2006

Environ Biol Fish

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Natural selection has been invoked to explain the observed geographic distribution of allozyme allele frequencies for a number of teleost species. The effects of selection on allozyme loci in three species of Pacific salmon were tested. A simulation-based approach to estimate the null distribution of population differentiation (F ST ) and test for F ST outliers was used. This approach showed that a majority of allozyme loci conform to neutral expectations predicted by the simulation model, with relatively few F ST outliers found. No consistent F ST outlier loci were found across species. Analysis of population sub-groups based on geography and genetic identity reduced the number of outlier loci for some species, indicating that large geographic groups may include genetically divergent populations and/or that there is geographic heterogeneity in selection pressure upon allozyme loci. Two outlier allozyme loci found in this analysis, lactate dehydrogenase-B and malic enzyme, have been shown to be influenced by selection in other teleost species. This approach is also useful in identifying allozyme loci (or other genetic markers) that meet assumptions for population genetic study.

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“…Summer and fall runs of chum salmon also occur in the same rivers in Hood Canal and Puget Sound tributaries, (Johnson et al 1997). While Hood Canal summer chum salmon form an ESU separate from Hood Canal fall chum salmon, Puget Sound summer and fall chum salmon form an ESU together (Phelps et al 1994;Johnson et al 1997). Similar to Puget Sound chum salmon, Cowlitz summer chum salmon are most closely related to Cowlitz fall chum salmon.…”

Section: Broad-scale Population Structurementioning

confidence: 99%

“…Supplementation with non-native fish likely had little genetic effect upon remaining native chum salmon since juveniles were planted in tributaries where native runs were extinct (Johnson et al 1997) and the modest efforts (mean less than 500,000 fry per year) failed to restore populations. Further, genetic analyses (Phelps et al 1994) indicated that lower Columbia River chum salmon remain genetically distinct from other chum salmon in Washington State that had been planted as hatchery fish. Despite supplementation efforts and a moratorium on commercial exploitation implemented in the late 1950s, the chum salmon run remains around 2500 fish, roughly 3% of historical abundance (WDFW 2000).…”

Section: Introductionmentioning

confidence: 99%

Genetic Structure of Chum Salmon (Oncorhynchus keta) Populations in the Lower Columbia River: Are Chum Salmon in Cascade Tributaries Remnant Populations?

et al. 2006

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The lower Columbia River drainage once supported a run of over a million chum salmon. By the late 1950s, the run had decreased to often a few hundred fish. With the exception of Grays River near the coast and an aggregation of chum salmon spawning in creeks and the main stem near Bonneville Dam in the Columbia Gorge, most populations were thought to be extinct. However, chum salmon consistently return in low numbers to tributaries originating in the Cascade Range: the Cowlitz, Lewis, and Washougal rivers. To assess whether Cascade spawners were strays or remnants of former populations, chum salmon from the Coastal, Cascade and Gorge ecoregional zones were characterized at 17 microsatellite loci. Significant heterogeneity in genotype distributions was detected between zones and collections formed regional groups in a neighbor-joining tree. Cascade collections had higher allelic richness and private alleles, and the Cowlitz River supported genetically divergent fall and summer runs, the only summer chum salmon run extant in the Columbia River drainage. We propose that chum salmon in the Cascade zone are remnants of original populations. We attribute the divergence between zonal groups to diverse ecological conditions in each zone, which promoted regional genetic adaptation, and to genetic drift experienced in small populations.

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Genetic Diversity Patterns of Chum Salmon in the Pacific Northwest

Cited by 46 publications

References 25 publications

Life-History Divergence in Chinook Salmon: Historic Contingency and Parallel Evolution

Life-History Divergence in Chinook Salmon: Historic Contingency and Parallel Evolution

Analysis of F ST outliers at allozyme loci in Pacific salmon: implications for natural selection

Genetic Structure of Chum Salmon (Oncorhynchus keta) Populations in the Lower Columbia River: Are Chum Salmon in Cascade Tributaries Remnant Populations?

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