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The Contribution Of Environment And Heredity To Differences In Freshwater Growth Between Birkenhead River And Weaver Creek Sockeye Salmon Oncorhynchus Nerka Microform
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Book Synopsis The Contribution of Environment and Heredity to Differences in Freshwater Growth Between Birkenhead River and Weaver Creek Sockeye Salmon, Oncorhynchus Nerka [microform] by : James Douglas Cave
Download or read book The Contribution of Environment and Heredity to Differences in Freshwater Growth Between Birkenhead River and Weaver Creek Sockeye Salmon, Oncorhynchus Nerka [microform] written by James Douglas Cave and published by National Library of Canada. This book was released on 1988 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Trends in the Freshwater Growth of Sockeye Salmon (Oncorhynchus Nerka) from the Wood River Lakes and Nushagak Bay, Alaska by : Mark Zimmermann
Download or read book Trends in the Freshwater Growth of Sockeye Salmon (Oncorhynchus Nerka) from the Wood River Lakes and Nushagak Bay, Alaska written by Mark Zimmermann and published by . This book was released on 1991 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Role of Life History and the Environment in Population Dynamics of Sockeye Salmon (Oncorhynchus Nerka) by : Douglas Clifford James Braun
Download or read book The Role of Life History and the Environment in Population Dynamics of Sockeye Salmon (Oncorhynchus Nerka) written by Douglas Clifford James Braun and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Processes linking the environment and life histories are central to our understanding of population dynamics. This thesis combines life history theory and environmental variation to explain recruitment dynamics among populations in Fraser River sockeye salmon (Oncorhynchus nerka). I first explore relationships between spawning stream characteristics and spawning densities and show that streams with more cover have higher spawning densities. Next, I use a 21-year time series for three of these populations to explore hypotheses about how maternal life history traits and migration conditions, experienced during upstream migrations to their spawning grounds, influence reproductive investment. Maternal body size is strongly linked to total reproductive investment and both egg mass and fecundity; however, migration difficulty only influences egg mass and not fecundity. Using the same dataset, I show that egg mass and incubation temperatures influence juvenile fitness-related traits including length, mass and emergence timing. The main finding from these analyses, that warmer incubation temperatures result in lighter juveniles that emerge earlier, led to hypotheses about how incubation temperature might select for egg size among populations. I tested these hypotheses by comparing 16 populations and confirmed the prediction that in streams with warmer water, fish would produce heavier eggs. I then asked if these same maternal traits and environmental conditions would relate to adult recruitment dynamics. Populations spawning in streams with deeper water had higher maximum population growth rates and less variable recruitment. In addition, populations in streams with larger gravel exhibited stronger density-dependence. Finally, I develop a novel framework for evaluating how habitat data, combined with the cost of collecting such information, can be used in developing cost-effective surveys. I demonstrate this general framework with a simple example using the relationships between stream characteristics and sockeye densities, considering the costs and effectiveness of stream variables. Overall, this demonstration of the joint role of maternal traits and environmental conditions in recruitment dynamics supports the potential use of such variables as indicators of population dynamics in the absence of long-term demographic data. Furthermore, it supports the development of cost-effective surveys, which is important as human impacts on populations increase, and as monitoring resources decline.
Book Synopsis A Comparison of the Growth Histories of Pre- and Post-decline Brood Years of Sockeye Salmon (Oncorhynchus Nerka) from Rivers Inlet Based on Otolith Analysis and in Relation to Environmental Conditions by : Claire Anne Li Loong
Download or read book A Comparison of the Growth Histories of Pre- and Post-decline Brood Years of Sockeye Salmon (Oncorhynchus Nerka) from Rivers Inlet Based on Otolith Analysis and in Relation to Environmental Conditions written by Claire Anne Li Loong and published by . This book was released on 2012 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: The widths of growth zones recorded on otoliths of sockeye salmon (Oncorhynchus nerka) from Rivers Inlet were measured to assess the impacts of environmental conditions on growth at different life history stages. Otoliths from the pre-decline (1984-1987) and post-decline brood years (1997-2005) were compared. Post-decline juveniles were significantly larger than pre-decline individuals during the migration to sea, but grew less in the first marine year. Final size was not significantly different between time periods. Functional regression analyses were performed to investigate the relationship between otolith growth and sea surface salinity at McInnes Island. Otolith growth was positively correlated with salinity during September and October. Decreased salinity under a 30 ppt threshold appears to have signalled recent unfavourable oceanic conditions for growth and possibly survival.
Book Synopsis Variation in the Early Life History of Sockeye Salmon (Oncorhynchus Nerka) by : Caryn A. Abrey
Download or read book Variation in the Early Life History of Sockeye Salmon (Oncorhynchus Nerka) written by Caryn A. Abrey and published by . This book was released on 2005 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ecology of Stream-dwelling Fishes in Response to Inter-annual Variation in the Abundance of Spawning Sockeye Salmon by : Kale T. Bentley
Download or read book Ecology of Stream-dwelling Fishes in Response to Inter-annual Variation in the Abundance of Spawning Sockeye Salmon written by Kale T. Bentley and published by . This book was released on 2014 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Each year, millions of salmon enter the final stage of their life-cycle and migrate back towards their natal watersheds to reproduce. After accumulating >95% of their adult body mass in marine environments, salmon spawning migrations generate massive fluxes of nutrients and energy to inland food webs that can exceed background levels of in situ productivity, and these resources are utilized by a wide range of taxa (Naiman et al. 2002, Gende et al. 2002, Schindler et al. 2003). However, one-half to three-fourths of all returning salmon are harvested by commercial fisheries in coastal oceans prior to reproducing, as salmon fisheries in Alaska are currently managed to maximize the long-term sustainable yield of salmon (Baker et al. 2009). Although this practice is widely touted as a fisheries management success story (Hilborn 2006), people are beginning to ask, what effect does removing the biomass of salmon prior to spawning have on freshwater and terrestrial ecosystems. Thus, there has been a call to shift the paradigm of fisheries management from one that focuses solely on maximizing the yield of single target species to a more holistic approach that accounts for other ecosystem processes (Pikitch et al. 2004, Crowder et al. 2008, Piccolo et al. 2009). In order to develop an ecosystem-based management approach, salmon managers need to be able to assess the trade-offs of different management scenarios that affect how many salmon are harvested versus released to the watershed (known as "escapement") to spawn and benefit inland ecosystems. Currently, assessing these trade-offs is difficult; while there is a well-established theory of how to optimize commercial catch based on stock-recruit relationships (Ricker 1954, Hilborn and Walters 1992, Quinn and Deriso 1999), we lack a quantitative understanding of how the number of salmon returning to spawn influences freshwater and terrestrial ecosystems. The focus of my thesis was to evaluate of the ecological response of Arctic grayling (Thymallus arcticus) and rainbow trout (Oncorhynchus mykiss), two species of resident fish that rely heavily on consumption of salmon resource subsidies (Scheuerell et al. 2007, Moore et al. 2008), to variation in the abundance of adult sockeye salmon (Oncorhynchus nerka) in the Wood River watershed, Bristol Bay, Alaska. The first chapter of my thesis assessed the ability of a body condition index to serve as a proxy for estimating individual instantaneous growth rates as obtaining direct measurements of growth can be time consuming, costly, and logistically impractical. We found that relative body condition of grayling and rainbow trout, as measured by the residuals around a length-mass regression, was strongly correlated with direct measures of individual instantaneous growth from recaptured tagged fish. Using the derived relationship between body condition and growth, we developed a model to estimate growth rates of individual fish based on their observed body condition. Chapter two evaluated the foraging and growth responses of grayling and rainbow trout in two streams that vary in in situ productivity to changes in the abundances of spawning sockeye salmon. Over 11 years, and across a greater than 10-fold variation in density of spawning sockeye salmon, both species of resident fish exhibited a relatively similar, but mechanistically different, saturating growth response to increasing salmon density. This growth response was driven by both an increase in consumption of salmon eggs and also a decrease in dietary overlap between the two species. However, the relative change in growth from low to high salmon densities was different between streams and depended on in situ stream productivity. In low salmon density years the growth of resident consumers fell 46-68% relative to high years in the low productivity stream, but only by 26-34% in the high productivity stream. Growth rates of both consumer species saturated in years when densities of sockeye salmon exceeded about 0.3 - 0.4 m2 on the spawning grounds. Chapter three evaluated the movement patterns of Arctic grayling and rainbow trout within and among streams, which offer patchily distributed foraging opportunities during the summer months. Across both years, approximately 50% of individual grayling and rainbow trout exhibited kilometer-scale movements among two or more streams across the river network within a single summer. Movements were concentrated in June and July, and subsided by early August, coincident with the arrival of spawning sockeye salmon (O. nerka). These inter-stream movements may represent prospecting behavior as individuals seek out the most profitable foraging opportunities. Thus, resident fishes in the Wood River system appear to use the broad network of habitat available to them across the riverscape, rather than depend on individual tributaries for achieving growth. Together the results of this thesis improve our understanding of how inland ecosystem respond to changes in salmon abundance. These results will be of use for resource managers interested in directly evaluating the socio-economic trade-offs of allocating salmon resources among user groups. The results of this work also highlight the importance of maintaining connectivity to enable movements of resident fish across river basins, the ecological consequences of which remain poorly understood.
Book Synopsis Response of Freshwater Fish Communities to Spawning Sockeye Salmon (Oncorhynchus Nerka) by : Daniel E. Eastman
Download or read book Response of Freshwater Fish Communities to Spawning Sockeye Salmon (Oncorhynchus Nerka) written by Daniel E. Eastman and published by . This book was released on 1996 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The migration patterns, food habits and the overall body condition of resident fish populations were characterized with particular reference to spawning activity of sockeye salmon (Oncorhynchus nerka) in the Wood River lake system, AK. Juvenile and adult char (Salvelinus sp.) and rainbow trout (Oncorhynchus mykiss) moved into three of the four small study streams as salmon began to spawn, consumed large quantities of salmon eggs and other salmon-derived food items, and in most cases grew significantly (in weight) throughout the summer. Tag-recapture results indicated that rainbow trout, char and Arctic grayling (Thymallus arcticus) were moving substantially within the streams and that trout and grayling were migrating between streams (2.7-3.9 km) within the lake. Prior to salmon spawning, stomachs contained only small aquatic and terrestrial insects and, most fish were visibly emaciated. In Pick Creek salmon-derived food items dominated (>90% by weight) the diets of most fish for more than a month, with some individuals' stomachs containing more than 1,000 salmon eggs. During this time period, most species in the four streams were significantly heavier due to a combination of increased food consumption and growth. There were also costs associated with feeding in these small streams, as was evidenced by the high frequency of wounds inflicted upon resident fish by aggressive, spawning salmon. Grayling preyed primarily upon aquatic insects and did not exhibit significant growth throughout the salmon spawning season. Salmon-derived resources promote summer growth in those species which capitalize on their seasonal availability and may enhance survival in Arctic regions where the summer growth period is short and winter is severe"--Author's abstract.
Book Synopsis Climate, Embryonic Development, and Potential for Adaptation to Warming Water Temperatures by Bristol Bay Sockeye Salmon by : Morgan McKenzie Sparks
Download or read book Climate, Embryonic Development, and Potential for Adaptation to Warming Water Temperatures by Bristol Bay Sockeye Salmon written by Morgan McKenzie Sparks and published by . This book was released on 2016 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapidly warming water temperatures associated with climate change represent a substantial disturbance to the habitat of aquatic ectothermic organisms. For salmonid fishes (family Salmonidae), early life history survival and timing of reproduction and development are closely tied to temperature, such that altered thermal regimes could alter patterns of survival or shift phenology into a mismatch with the environment. Because temperature is the dominant driver of developmental rates, empirical statistical models have been developed to predict the timing of hatching and fry emergence based on incubation temperature. In this thesis I explored how the timing of hatching and emergence may shift in response to warming temperatures and how spawning timing across an Alaskan landscape is shaped by incubation temperatures experienced by sockeye salmon (Oncorhynchus nerka) embryos and alevin. Additionally, I quantified the relative roles of genetics and environmentally induced plasticity on the timing of hatching in two populations of sockeye salmon from the Iliamna Lake system, Alaska by rearing them in common garden conditions in the laboratory. To meet these goals I reformulated a widely cited developmental model to incorporate variability in natural regimes and use it to predict hatching timing over the course of the spawning duration for 25 populations of Bristol Bay sockeye salmon. Additionally, I hind- and forecasted lake temperature based off historical and predicted air temperatures to estimate and predict hatching for a single population. I found that predicted hatching timing for wild populations varied between 58 and 260 days, and was largely variable as a result of habitat thermal heterogeneity and parental spawn time. I also predicted a three-week decrease in hatching timing over the course of the next century for a single beach spawning population, which was just beyond historic variability. Counter to expectations, for a subset of populations hatching and emergence timing variability exceeded that of spawning timing, indicating the relationship between spawning timing and incubation temperature may be weaker than expected. The results of the common garden experiment revealed indistinguishable differences between populations in hatching timing across five temperature scenarios, but strong plasticity as timing differed between 74 and 189 days in the warmest to coolest treatment. Furthermore, I detected family-specific differences in hatching timing both within and among treatments consistent with heritable developmental rates and gene by environment interactions in days to hatch, where the interaction between treatment and family was as high as 10 days difference in hatching. Population or family-specific survival in this experiment did not differ in response to temperature suggesting a lack of thermal adaptation in this regard during this life stage in these populations. Alevin mass and length upon hatching varied little among treatments (
Book Synopsis Functional Ecology and Evolution of Sockeye Salmon (Oncorhynchus Nerka) Life History in the Dynamic Environments of Aniakchak and Katmai by : Scott Anthony Pavey
Download or read book Functional Ecology and Evolution of Sockeye Salmon (Oncorhynchus Nerka) Life History in the Dynamic Environments of Aniakchak and Katmai written by Scott Anthony Pavey and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sockeye salmon exhibit great ecological diversity among populations. During the last glacial period, ice covered much of what today are freshwater habitats. As the glaciers retreated, sockeye colonized new freshwater habitats from relatively few glacial refugia. Colonizing populations adapted at a very fine spatial scale among river drainages, tributaries and lakes within rivers, and even divergent habitats within lakes. All of this occurred within the past 15,000 years since the last glacial maximum. This resulted in many thousands of locally adapted populations and a grand display of the process of evolution within a species. In this dissertation, I explore genetic and phenotypic diversity in the dynamic and changing environments of Aniakchak National Monument and Preserve as well as Katmai National Park in southwest Alaska. Recent eruptions at Aniakchak include events 500 and 79 years ago and the caldera presently contains sockeye salmon populations spawning in different habitats. Using genetic tools, I find that ecological divergence occurred in egg size and body depth in less than 500 years or 100 generations. Secondly, sockeye salmon exhibit a broad life history division by rearing habitat; some populations rearing in lakes (lake-type sockeye) and others rearing in rivers (riverine sockeye). I describe differences in juvenile body shape and relate these to differences in foraging strategy and predation. Finally, I apply gene expression technology to understand the life history differences and the molecular trade-offs in sockeye salmon populations. I start with a review of recent technological advances that relate gene expression to ecology, evolution, and the formation and maintenance of new species. I then relate functional, expressed genes in muscle tissue to lake-type and riverine juvenile populations. This provides an ecological context to genes that are normally only described in artificial situations. Taken together, this work furthers the understanding of the interaction of ecology and evolution, from genes to populations to broad life history types.
Book Synopsis Connecting Physiological Condition with Salinity Preference Behaviour to Infer Estuary Habitat Choice in Sockeye Salmon Smolts (Oncorhynchus Nerka) by : Daniella LoScerbo
Download or read book Connecting Physiological Condition with Salinity Preference Behaviour to Infer Estuary Habitat Choice in Sockeye Salmon Smolts (Oncorhynchus Nerka) written by Daniella LoScerbo and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The time period in which juvenile salmon remain in an estuary varies greatly among and within populations, with some individuals passing through estuaries in a matter of hours, while others remain in the estuary for several months. This individual variation in estuary use suggests that there may be underlying differences in individual salmon condition that temporally mitigate the selection of habitat, such as smolt size (fork length, mass, condition factor), stored energy (lipids and proteins), and osmoregulatory function (gill N+-K+-ATPase activity, NKA). I investigated the role of physical and physiological condition on the selection of estuarine and ocean habitat by sockeye salmon (Oncorhynchus nerka) smolts intercepted at the initiation of their downstream migration from Chilko Lake, Fraser River, B.C.. Since juvenile salmon energetic costs increase with rising salinity, I expected that smolts of lower physiological condition (i.e. low condition factor, poor energetic status and low NKA) would prefer to remain in the freshwater environment of the estuary, while smolts of higher physiological condition would prefer saline waters in the estuary and potentially indicate more rapid ocean entry. Behavioural salinity preference experiments were conducted on unfed smolts (n = 263) held in freshwater at three time intervals during their downstream migration period, representing the expected timing for lake exit, estuary entry, and ocean entry, at 0, 1, and 3 weeks respectively. Smolt condition factor (K), energetic stores and NKA predicted salinity preference behaviour in the estuary and ocean outmigration stages, but not at lake exit. Our results suggest that smolt physiological condition upon reaching the estuary may influence migratory behaviour and habitat selection, providing novel evidence on the temporally dependent interplay of physiology, behaviour and migration in wild juvenile Pacific salmon. As juvenile migratory behaviour is linked to physiological condition, and physiological condition is determined by productivity and competition within the rearing habitat, the importance of estuaries likely varies across years and within a population cohort; thus estuaries may be of heightened importance for wild juvenile salmon in years of poor freshwater growth conditions. These findings support the growing body of evidence on the importance of conserving both rearing habitat for juvenile growth potential and estuarine habitat for smolt refugia before ocean entry.
Book Synopsis 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 by : Patrick D. Barry
Download or read book 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 written by Patrick D. Barry and published by . This book was released on 2021 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Author :Guthrie, Ian C. (Ian Campbell) Publisher :National Library of Canada ISBN 13 :9780315307124 Total Pages :282 pages Book Rating :4.3/5 (71 download)
Book Synopsis Effect of Density-dependent Marine Growth on the Economically Optimal Lake Enrichment Strategy for British Columbia Sockeye Salmon (Oncorhynchus Nerka) [microform] by : Guthrie, Ian C. (Ian Campbell)
Download or read book Effect of Density-dependent Marine Growth on the Economically Optimal Lake Enrichment Strategy for British Columbia Sockeye Salmon (Oncorhynchus Nerka) [microform] written by Guthrie, Ian C. (Ian Campbell) and published by National Library of Canada. This book was released on 1985 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ecological Drivers of Variation in Juvenile Sockeye Salmon Marine Migrations by : Cameron Freshwater
Download or read book Ecological Drivers of Variation in Juvenile Sockeye Salmon Marine Migrations written by Cameron Freshwater and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Animal migrations are often associated with high mortality due to increased energy expenditure, reduced foraging opportunities, and increased predation risk. Migratory traits such as body size, phenology, or use of stopover habitats may moderate individual risk to mortality mechanisms and influence patterns of survival. However, variability in migratory traits is rarely quantified in detail because tracking many individuals over large areas is logistically challenging. In this dissertation, I used otoliths to examine migratory variability among and within sockeye salmon (Oncorhynchus nerka) populations, a species that has recently experienced declines associated with poor survival during juvenile marine migrations. Broadly, I examined the individual and environmental drivers of migratory patterns, as well as how variation across ecological scales (individuals, populations, and years) contributed to migratory diversity. First, I conducted a laboratory study to validate the use of otolith microstructure techniques in sockeye salmon post-smolts. Next, I assessed how a suite of ecological processes could interact to create a latitudinal gradient in sockeye salmon body size. By reconstructing individual growth and migration histories I determined that variation in size was correlated with ocean entry size and phenology, rather than differential marine growth or size-selective mortality. I then used estimates of migratory rate from otoliths to demonstrate that juvenile sockeye salmon exhibited distinct migratory phenotypes associated with ocean entry traits. Larger individuals migrated rapidly offshore, while smaller fish reared for several weeks in nearshore regions. Furthermore, a subset of the smallest individuals entered the ocean late in the year, migrated particularly slowly, and may have overwintered on the continental shelf. These linkages between ocean entry and migratory traits suggest juvenile sockeye salmon exhibit substantial migratory plasticity associated with carry-over effects from freshwater residence; however juvenile salmon may also respond strongly to variable conditions in marine habitats. In my fifth chapter, I compared marine growth and migration phenology in years with low and high competitor densities. After accounting for freshwater density-dependent effects, growth rates were similar in both years, but mean migration rates were nearly 50% faster in the high-density year. Migratory behavior may be used to buffer individuals from the effect of competitive interactions. In my final chapter, I sampled 16 Fraser River sockeye salmon populations to explore variation in the timing and duration of early marine migrations. Although populations differed in downstream migration timing, as well as their duration of residence within nearshore habitats, there was substantial variation within each population and between sampling years. These findings suggest individual characteristics and stochastic processes interact with population-specific strategies to shape migratory phenologies in this metapopulation. Management actions should account for and preserve migratory diversity at multiple ecological scales to maintain resilient salmon populations into the future.
Book Synopsis Using Stock-Specific Thermal Physiology to Simulate In-River Mortality of Fraser River Sockeye Salmon by : Jennifer Karen Carter
Download or read book Using Stock-Specific Thermal Physiology to Simulate In-River Mortality of Fraser River Sockeye Salmon written by Jennifer Karen Carter and published by . This book was released on 2014 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annual estimates of mortality en-route to spawning grounds for certain populations of Fraser River Sockeye salmon (Oncorhynchus nerka) can routinely exceed 50% posing challenges for harvest management and salmon conservation. High estimates of mortality are also correlated with high migration temperatures, suggesting temperature is one of the main factors. However, these estimates of apparent mortality are uncertain as they currently rely on discrepancies between up-river spawning ground estimates and lower river escapement estimates adjusting for estimates of in-river catch. Therefore, applying thermal physiology may serve as a tool to explain the potential contribution temperature-related mortality could have in calculating annual apparent mortality estimates for specific populations. I incorporated short- and long-term mortality functions based on population-specific aerobic scope temperature thresholds and an aggregate accumulation of degree-days threshold to a simulation model to estimate en-route mortality associated with temperature exposure for six Fraser River Sockeye salmon populations: Early Stuart, Gates Creek, Stellako, Chilko, and Weaver Creek. I compared simulated temperature based mortality rates to apparent mortality estimates (i.e. difference between estimates) and tested model sensitivity to uncertainty in short- and long-term LD50, arrival timing, and movement rate parameters. Results show that high temperature is likely a key driver of large en-route loss as both simulated mortality and apparent mortality estimates were higher in warmer years and lower in cooler years. I attribute the simulated mortality rates being generally lower than apparent mortality to the role that other sources of mortality can play (e.g. source error, high discharge). Simulated mortality rates were most sensitive to the short-term LD50 parameter, followed by the long-term LD50 and arrival timing parameters. However, simulated mortality rates were not sensitive to changes in movement rates. The model can explain temperature-related population-specific differences in apparent mortality between co-migrating populations (e.g., up to 80% absolute differences between Chilko and co-migrating populations) and provides evidence that these differences are driven by differences in aerobic scope. My results could inform managers of the relative importance of key parameters (short- and long-term mortality, and arrival timing) when estimating population-specific temperature-related mortality.
Book Synopsis Genetic and Phenotypic Diversity in Sockeye Salmon, Oncorhynchus Nerka by : Caroline Storer
Download or read book Genetic and Phenotypic Diversity in Sockeye Salmon, Oncorhynchus Nerka written by Caroline Storer and published by . This book was released on 2012 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work described here was motivated by a need for improved genetic tools for the management of sockeye salmon, specifically those populations inhabiting Bristol Bay, and a desire to better understand the process of senescence in Pacific Salmon. The first chapter details the development and evaluation of single nucleotide polymorphisms assays for sockeye salmon. With hundreds or thousands of SNPs potentially available, there is interest in comparing and developing methods for evaluating SNPs to create panels of high-throughput assays that are customized for performance, research questions, and resources. Here we use five different methods to rank 43 new SNPs and 71 previously published loci for sockeye salmon: FST, informativeness (In), average contribution to principal components (LC), and the locus-ranking programs BELS and WHICHLOCI. We then tested the performance of these different ranking methods by creating 48- and 96-SNP panels of the top-ranked loci for each method and used empirical and simulated data to obtain the probability of assigning individuals to the correct population using each panel. The second chapter details the development of five new gene expression assays to investigate the mechanisms driving senescence in Pacific salmon. We assessed five different physiological processes that might be involved in senescence (olfaction, immune response, reproduction, memory, and aging) using these new assays. While expression was higher in senescent fish for all five genes surveyed there were only significant differences in expression for two genes: Viperin (immune) and TERT (aging).
Download or read book Data Record written by H. T Bilton and published by . This book was released on 1971 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Drivers and Fitness Consequences of Dispersal and Structure in Wild Sockeye Salmon Populations (Oncorhynchus Nerka) by : Samuel Alexander May
Download or read book Drivers and Fitness Consequences of Dispersal and Structure in Wild Sockeye Salmon Populations (Oncorhynchus Nerka) written by Samuel Alexander May and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The life histories of migratory species such as salmonids, sea turtles, and birds often involve return migrations between feeding and natal habitats. These natal homing behaviors are known to produce structured metapopulations, where geographic and demographic barriers result in non-random mating among many locally adapted subpopulations. The resulting spatial and temporal diversity across heterogeneous landscapes can buffer metapopulations against disruptive events that influence any one subunit. Dispersal and gene flow within and between subpopulations can reduce fitness losses due to inbreeding depression, influence rates of adaptation, and facilitate colonization or recolonization of newly available habitat. However, an understudied aspect of metapopulation biology is the influence of biotic and abiotic factors that lead to genetic structure within and between subpopulations, and the effects of this structure on fitness. Therefore, the overall goal of this thesis was to investigate how environmental, behavioral, and life-history variation might influence dispersal, population structure, and fitness within and between subpopulations. To accomplish this goal, dispersal within and between two proximate stream-spawning populations of Sockeye salmon (Oncorhynchus nerka): A and C Creeks on the Wood River System, Bristol Bay, AK was studied over two complete generations of returning adults. First, a panel of 172 SNP loci was developed (genotyping-in-thousands by sequencing; Chapter One) and used to reconstruct a pedigree from fish returning over a 14-year period, and to identify dispersers between the two populations. Second, we investigated the drivers and fitness consequences of dispersal between A and C Creeks and found that return timing to spawning grounds and within-season variation in predation and population density influenced dispersal between the two populations (Chapter Two). Fitness consequences of dispersal depended on the direction dispersers moved; moving from A to C increased absolute fitness of dispersers (compared to individuals in their natal population) but decreased their relative fitness (compared to individuals in their new spawning population), while moving from C to A decreased absolute fitness but increased relative fitness. From these results, we concluded that dispersal was an active process in response to environmental cues and that gene flow was affected by habitat differences and within-season variation in ecological processes. Third, we aimed to examine the extent, drivers, and fitness consequences of population structure within the two streams. To achieve this aim, we quantified the scale of structure, the effect of natal homing on structure, and the fitness outcomes of homing to, and dispersing from natal sites (Chapter Three). Both spatial and temporal genetic structure was evident within both streams, and this structure was partly explained by adults returning to the same place and at the same time as they were fertilized as eggs. In addition, phenotypes of body size and return timing were spatially segregated within the creeks. In one of the two creeks, adults returning to spawn near natal sites had greater fitness. Taken together, we concluded that these findings provided empirical evidence for how natal homing and heterogeneous habitat may lead to assortative mating systems and possible microgeographic adaptation on very small spatial and temporal scales. In other words, natal homing and dispersal within populations may result in genetic or phenotypic neighborhoods and affect fitness. Finally, we discuss the utility of these findings for predicting responses of natural populations to future environmental and anthropogenic changes such as harvest, climate change, and supportive breeding.
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