Temporal variation in selection on body length and date of return in a wild population of coho salmon, Oncorhynchus kisutch

Kodama, Miyako; Hard, Jeffrey J.; Naish, Kerry A.

doi:10.1186/1471-2148-12-116

Cited by 19 publications

(21 citation statements)

References 64 publications

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“…Thus, although selective effects from previous years could have affected our observations, these effects may not have been strong. Selection coefficients estimated previously for adult Pacific salmon have found directional and stabilizing selection on body size (Carlson et al, 2009;Kodama et al, 2012) and directional selection on arrival date to the spawning grounds (Anderson et al, 2010), although modes of selection were often not consistent annually. The selection coefficients estimated here were within the range of estimates obtained in a study of wild coho salmon that also used ZINB regression models, and our sample sizes per brood year and population were of a similar order of magnitude (Kodama et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

It’s a bear market: evolutionary and ecological effects of predation on two wild sockeye salmon populations

et al. 2016

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Predation can affect both phenotypic variation and population productivity in the wild, but quantifying evolutionary and demographic effects of predation in natural environments is challenging. The aim of this study was to estimate selection differentials and coefficients associated with brown bear (Ursus arctos) predation in wild sockeye salmon (Oncorhynchus nerka) populations spawning in pristine habitat that is often subject to intense predation pressure. Using reconstructed genetic pedigrees, individual reproductive success (RS) was estimated in two sockeye salmon populations for two consecutive brood years with very different predation intensities across brood years. Phenotypic data on individual adult body length, body depth, stream entry timing and reproductive lifespan were used to calculate selection coefficients based on RS, and genetic variance components were estimated using animal models. Bears consistently killed larger and more recently arrived adults, although selection differentials were small. In both populations, mean RS was higher in the brood year experiencing lower predation intensity. Selection coefficients were similar across brood years with different levels of predation, often indicating stabilizing selection on reproductive lifespan as well as directional selection for longer reproductive lifespan. Despite these selection pressures, genetic covariation of morphology, phenology and lifespan appears to have maintained variation in spawner body size and stream entry timing in both populations. Our results therefore suggest considerable demographic but limited evolutionary effects of bear predation in the two study populations.

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Section: Discussionmentioning

confidence: 99%

It’s a bear market: evolutionary and ecological effects of predation on two wild sockeye salmon populations

et al. 2016

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“…In addition to its importance in the marketplace, coho salmon provides a conservation and evolutionary model for study among the salmonids. This species of salmon is strictly anadromous and semelparous, with a shorter generation time and a simpler life history than most other salmonids (Kodama et al 2012), although population dynamics are still actively being examined (Jones et al 2014). We are interested in the increased growth hormone production of the GH + coho salmon strain (Devlin et al 2001) as a model along with its potential differences from wild-types under natural and/or aquaculture stressors.…”

Section: Introductionmentioning

confidence: 99%

Food Shortage Causes Differential Effects on Body Composition and Tissue-Specific Gene Expression in Salmon Modified for Increased Growth Hormone Production

Abernathy¹,

Panserat²,

Welker³

et al. 2015

Mar Biotechnol

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Growth hormone (GH) transgenic salmon possesses markedly increased metabolic rate, appetite, and feed conversion efficiency, as well as an increased ability to compete for food resources. Thus, the ability of GH-transgenic fish to withstand periods of food deprivation as occurs in nature is potentially different than that of nontransgenic fish. However, the physiological and genetic effects of transgenic GH production over long periods of food deprivation remain largely unknown. Here, GH-transgenic coho salmon (Oncorhynchus kisutch) and nontransgenic, wild-type coho salmon were subjected to a 3-month food deprivation trial, during which time performance characteristics related to growth were measured along with proximate compositions. To examine potential genetic effects of GH-transgenesis on long-term food deprivation, a group of genes related to muscle development and liver metabolism was selected for quantitative PCR analysis. Results showed that GH-transgenic fish lose weight at an increased rate compared to wild-type even though proximate compositions remained relatively similar between the groups. A total of nine genes related to muscle physiology (cathepsin, cee, insulin-like growth factor, myostatin, murf-1, myosin, myogenin, proteasome delta, tumor necrosis factor) and five genes related to liver metabolism (carnitine palmitoyltransferase, fatty acid synthase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, glucokinase) were shown to be differentially regulated between GH-transgenic and wild-type coho salmon over time. These genetic and physiological responses assist in identifying differences between GH-transgenic and wild-type salmon in relation to fitness effects arising from elevated growth hormone during periods of long-term food shortage.

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“…Importantly, tissue samples for DNA and phenotypic data have been collected from every adult fish used as broodstock since the inception of the program in 1997. Many of the phenotypic traits measured-length, weight, and dates of return to freshwater and maturation-are correlated with individual fitness (e.g., Kodama, Hard, & Naish, 2012;Schroder et al, 2010;Thorpe, Miles, & Keay, 1984). In addition, these traits have significant additive genetic variation on which selection can act (Carlson & Seamons, 2008;Hard, 2004) and can differ between hatchery and wild populations (e.g., Ford et al, 2006;Hoffnagle, Carmichael, Frenyea, & Keniry, 2008;Knudsen et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Genomewide association analyses of fitness traits in captive‐reared Chinook salmon: Applications in evaluating conservation strategies

Waters

Hard

Brieuc

et al. 2018

Evolutionary Applications

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A novel application of genomewide association analyses is to use trait‐associated loci to monitor the effects of conservation strategies on potentially adaptive genetic variation. Comparisons of fitness between captive‐ and wild‐origin individuals, for example, do not reveal how captive rearing affects genetic variation underlying fitness traits or which traits are most susceptible to domestication selection. Here, we used data collected across four generations to identify loci associated with six traits in adult Chinook salmon (Oncorhynchus tshawytscha) and then determined how two alternative management approaches for captive rearing affected variation at these loci. Loci associated with date of return to freshwater spawning grounds (return timing), length and weight at return, age at maturity, spawn timing, and daily growth coefficient were identified using 9108 restriction site‐associated markers and random forest, an approach suitable for polygenic traits. Mapping of trait‐associated loci, gene annotations, and integration of results across multiple studies revealed candidate regions involved in several fitness‐related traits. Genotypes at trait‐associated loci were then compared between two hatchery populations that were derived from the same source but are now managed as separate lines, one integrated with and one segregated from the wild population. While no broad‐scale change was detected across four generations, there were numerous regions where trait‐associated loci overlapped with signatures of adaptive divergence previously identified in the two lines. Many regions, primarily with loci linked to return and spawn timing, were either unique to or more divergent in the segregated line, suggesting that these traits may be responding to domestication selection. This study is one of the first to utilize genomic approaches to demonstrate the effectiveness of a conservation strategy, managed gene flow, on trait‐associated—and potentially adaptive—loci. The results will promote the development of trait‐specific tools to better monitor genetic change in captive and wild populations.

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Temporal variation in selection on body length and date of return in a wild population of coho salmon, Oncorhynchus kisutch

Cited by 19 publications

References 64 publications

It’s a bear market: evolutionary and ecological effects of predation on two wild sockeye salmon populations

It’s a bear market: evolutionary and ecological effects of predation on two wild sockeye salmon populations

Food Shortage Causes Differential Effects on Body Composition and Tissue-Specific Gene Expression in Salmon Modified for Increased Growth Hormone Production

Genomewide association analyses of fitness traits in captive‐reared Chinook salmon: Applications in evaluating conservation strategies

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