Author: Stanislav Maksimovich KonovalovPublisher:
ISBN:
Category : Sockeye salmon
Languages : en
Pages : 0
Book Description
Differentiation of Local Populations of Sockeye Salmon
Author: Stanislav Maksimovich KonovalovPublisher:
ISBN:
Category : Sockeye salmon
Languages : en
Pages : 0
Book Description
Serological Differentiation of Populations of Sockeye Salmon, Oncorhynchus Nerka
Author: George J. RidgwayPublisher:
ISBN:
Category : Sockeye salmon
Languages : en
Pages : 20
Book Description
Genetic Differentiation of Sockeye Salmon (Oncorhynchus Nerka) Populations in the Wood River Lakes of Bristol Bay, Alaska
Author: Marcia Marie BenderPublisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 130
Book Description
NOAA Technical Report NMFS.
Author: Microevolution, Local Adaptation, and Demography in Wild Populations of Pacific Salmon
Author: Jocelyn LinPublisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 245
Book Description
There is increasing scientific interest in empirically linking evolution to ecology, particularly in wild populations. Although evolutionary change is often thought to proceed slowly, the microevolutionary forces of selection, gene flow, genetic drift and inbreeding can have pronounced effects on genetic variation even on short time scales. These genetic changes may then influence local adaptation and demography. The overarching aim of this dissertation was to estimate levels of gene flow and selection in wild populations, and to assess how microevolutionary change might affect local adaptation and population dynamics within these populations. Pacific salmon (Oncorhynchus spp.) are an ideal model organism for studying natural patterns of microevolution and local adaptation. First there is high phenotypic variation within the species, and spawning fish can be sampled comprehensively by capturing adults when they return to freshwater from the ocean. Second, salmon form reproductively isolated spawning populations due to natal homing, but these populations can be genetically and demographically connected via straying. Third, salmon are of ecological and commercial interest, making our findings relevant to population management. This dissertation investigated ecology and evolution in salmon as follows. In Chapter 1, we examined patterns of genetic and phenotypic differentiation between adjacent populations of beach and stream spawning ecotypes of sockeye salmon, and assessed potential levels of gene flow between ecotypes. The objective of Chapter 2 was to determine whether small populations of Chinook and chum salmon occurring in the Wood River system are reproductively isolated, self-sustaining populations, population sinks that produce returning adults but receive immigration, or strays from other systems that do not produce returning adults. In Chapter 3 we re-constructed pedigrees for two wild populations of sockeye salmon to estimate natural selection and heritability for several phenotypic traits. For Chapter 4, we used empirical results from the first three chapters to develop a stochastic, individual-based model that we used to study effects of gene flow and selection on local adaptation and population dynamics in interconnected salmon populations. Taken together, these studies showed how gene flow and selection affect local adaptation and demography in wild salmon populations.
A History of Sockeye Salmon Research, Karluk River System, Alaska, 1880-2010
Author: Richard GardPublisher:
ISBN:
Category : Sockeye salmon
Languages : en
Pages : 428
Book Description
Sockeye Salmon (Onchorhynchus Nerka) in Lake Washington
Author: Andrew Paul HendryPublisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 318
Book Description
Spatio-temporal Genetic Structure, Effective Population Size, and Parentage Simulations from Contemporary Genetic Samples and Historic Demographic Data of Sockeye Salmon (Oncorhynchus Nerka) in Auke Lake, Alaska
Author: Patrick D. BarryPublisher:
ISBN:
Category : Pacific salmon
Languages : en
Pages : 312
Book Description
Pacific salmon (Oncorhynchus spp.) have great ecological, economic, and cultural importance. Accordingly, understanding the genetic diversity of Pacific salmon populations is critical for their effective management and conservation. Spatial and temporal homing fidelity, a central life-history characteristic of Pacific salmon, generates genetic structure through reproductive isolation. Within and among populations, heterogeneity in the freshwater environment should lead to selection for traits that maximize fitness resulting in local adaptation. This adaptation increases productivity of individual populations while diversity among populations can promote long-term stability. Additionally, the demographic properties (age structure, generation length, size) of a population will affect genetic structure by regulating its response to the evolutionary forces of selection, migration, and genetic drift. The scale and extent to which reproductive isolation can produce genetic structure is incompletely understood. In this dissertation, I investigated spatial and temporal trends in population genetic structure and estimated the effective population size (Ne) of Sockeye Salmon from Auke Lake in Southeast Alaska from contemporary genetic samples (2008, 2009, 2011) and historic demographic data (1980–2017). A simulation library in the R statistical environment was developed to assess the accuracy of parentage and sibship inference from genetic markers. This library proved useful in evaluating the sibship method for estimating Ne from genetic data and evaluating genetic markers for a large-scale parentage project. I detected substantial genetic differentiation between Auke Lake and other Southeast Alaska populations (average FST = 0.1137) and an isolation-by-time pattern within the Auke Lake population. A genetically distinct cluster was identified in the late portion of the 2008 return. This group may represent a spatially segregated spawning aggregation previously described in tagging studies; however, because fish were sampled as they passed through the weir, spatial structure within Auke Lake could not be evaluated. Genetic tests for demographic change within the population indicated that the Auke Lake Sockeye Salmon population underwent a historical bottleneck event but has since increased in size. Demographic estimates of Ne from a long-term dataset from the Auke Creek weir revealed that the effective population size was low in the early 1980s and has since increased. Over the six generations evaluated, the major demographic factors that determined Ne were variance in family size, variable contribution to the next generation by brood years within a generation, and fluctuations in population size. Contemporary estimates of Ne from genetic methods were smaller than those from demographic methods and indicated that Ne may be roughly the size of an individual return year. Genetic estimates of the ratio of the effective population size to the census size (Ne/Nc = 0.21) were consistent with values previously reported for other salmonids. Collectively, these chapters contribute to an improved understanding of Sockeye Salmon population genetics and provide a useful tool to assess the power of genetic markers for parentage and sibship inference.
Local Adaptation, Dispersal, and Gene Flow in a Metapopulation of Sockeye Salmon
Author: Daniel Alexander PetersonPublisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 91
Book Description
Gene flow within a metapopulation depends on the reproductive success of dispersers after immigration, but few empirical studies have measured the reproductive contributions of dispersers from distinct natal populations. The local adaptation frequently observed within metapopulations of anadromous salmonids could exert strong selection against immigrants with phenotypes adapted to ecologically distinct habitats. Used was genetic parentage analysis to directly measure the reproductive success of dispersers from multiple natal habitats relative to philopatric individuals within a group of geographically proximate but ecologically and genetically distinct subpopulations of stream- and beach-spawning sockeye salmon (Oncorhynchus nerka). Results indicate that dispersers between stream-spawning populations and philopatric individuals experienced similar reproductive success, while immigrants from the beach habitat to the streams produced fewer returning adult offspring than either philopatric individuals or stream-to-stream dispersers. The difference in reproductive contribution between beach-to-stream dispersers and the other two dispersal categories was estimated to be one returning adult offspring per individual. Thus, the difference in reproductive success of dispersers between habitat types represents a strong barrier to gene flow between these sockeye salmon ecotypes. Experimental and observational studies of the homing and spawning behavior of hatchery-raised salmon have indicated that their search for high-quality spawning habitat can overcome their homing tendency. Nevertheless, the extent to which dispersal between populations is motivated by habitat selection versus navigational errors during the homing process is not well understood, especially in wild populations. Examined were whether dispersing individuals exhibited more exploratory behavior than philopatric individuals within a metapopulation of wild sockeye salmon, which would suggest that dispersal may be influenced by comparisons between potential spawning areas. The daily locations of all adult salmon spawning in two proximate streams were tracked and determined the dispersal status for each individual by comparing its chosen spawning stream with that of its parents (as determined by genetic parentage reconstruction). Dispersers were often observed in their natal stream (8-11% of individuals) or at its mouth (29-58% of individuals) before spawning in the other stream, whereas philopatric individuals were rarely observed in their non-natal stream (0-2% of individuals) or at its mouth (1-7% of individuals). These results suggest either that the mechanism of dispersal encourages exploration or that individuals that explore are more likely to disperse. In either case, dispersers are exposed to multiple spawning habitats, potentially allowing annual variation in local environmental or demographic conditions to influence the patterns of gene flow within a metapopulation.
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