Download or read book Temporal and Spatial Differences in Smolting Among Sockeye Salmon Oncorhynchus Nerka Populations Throughout Fresh and Seawater Migration and the Effect of Water Temperature on the Smolt Window written by Marley Carter Bassett and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Salmon smolts undergo physiological changes in the spring that are important for successful migration to seawater. Species that are widely distributed may differ in timing of physiological changes associated with smelting. In my first study, I compared indices of smolt characteristics among populations that differ in migration distance to the ocean. Fraser River sockeye salmon from four regions in the watershed were intercepted at different times during migration to characterize the parr-smolt transformation. Gill Na+/K+-ATPase (NKA) activity was highly variable at the start of migration, and was not explained by the distance from the ocean. Gill NKA activity changes with migration were also highly variable, but consistently smolts in the ocean had the highest gill NKA activities. The nature of smelting appears to be dynamic and variation was not based on the region of origin, timing during migration, or on the year of migration. The duration of time when anadromous salmon are able to survive in seawater – the smolt window – is influenced by temperature. In my second study, I found that warm water temperature abbreviated the smolt window. Additionally, isoforms of the gill NKA enzyme and endocrine signals suggest that the stimulus for smelting occurred prior emigration from the natal lake. Modeling the thermal experience that smolts encountered as they migrated downstream to the ocean in 2012 suggested Chilko fish did not experience temperatures as warm as the temperatures that abbreviated the smolt window in my study. Furthermore, climate change projections for temperature may not limit successful emigration of Chilko sockeye salmon smolts from central British Columbia to the ocean – but changes in other abiotic and biotic factors may confound this prediction."--Leaf ii.
Download or read book Regional and Climate driven Factors Affecting the Migrations of Sockeye Salmon Oncorhynchus Nerka Smolts in Alaska written by Christopher R. Dailey and published by . This book was released on 2020 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The downstream migration of salmon smolts is triggered by a combination of responses to multiple environmental indicators, imposed on internal circannual rhythms, that result in variation between populations in timing. Using long-term data on daily smolt counts and associated environmental variables from multiple sources across Alaska, I tested the hypothesis that variation in migration timing between different sockeye salmon populations could be explained by differences in local environmental conditions. I first analyzed the peak, width, and interannual variation of the smolt migration period for eight populations from southwestern and southcentral Alaska. I then modeled the median emigration date and width of the emigration period as a function of stream temperature, air temperature, and precipitation to assess how each population responds to combinations of seasonal environmental cues that serve as indicators for the onset of downstream migration or conditions in the recipient environment (sea surface temperature). Lastly, I used the results of my analysis to identify spatial variation in the response of distinct salmon populations to environmental factors and identify trends in the migration timing of those populations. Through my analysis, I found that sea surface temperature and freshwater temperature are the primary environmental factors that control median smolt emigration date, while the width of the smolt emigration window is influenced primarily by freshwater temperatures and precipitation, with significant site-by-site variation.
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:
Download or read book Fish Larval Physiology written by Roderick Nigel Finn and published by CRC Press. This book was released on 2020-04-30 with total page 741 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended as a resource for students and researchers interested in developmental biology and physiology and specifically addresses the larval stages of fish. Fish larvae (and fish embryos) are not small juveniles or adults. Rather they are transitionary organisms that bridge the critical gap between the singlecelled egg and sexually immature juvenile. Fish larvae represent the stage of the life cycle that is used for differentiation, feeding and distribution. The book aims at providing a single-volume treatise that explains how fish larvae develop and differentiate, how they regulate salt, water and acid-base balance, how they transport and exchange gases, acquire and utilise energy, how they sense their environment, and move in their aquatic medium, how they control and defend themselves, and finally how they grow up.
Download or read book Spatial and Temporal Patterns of Homeward Migration and Population Structure in Sockeye Salmon Oncorhynchus Nerka in the Wood River System Bristol Bay Alaska written by Katy K. Doctor and published by . This book was released on 2008 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book On the Orientation of Young Sockeye Salmon Oncorhynchus Nerka During Their Seaward Migration Out of Lakes written by Cornelis Groot and published by . This book was released on 1965 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth and Survival of Sockeye Salmon Introduced Into Ruth Lake After Removal of Resident Fish Populations written by William R. Meehan and published by . This book was released on 1966 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Ecology of Atlantic Salmon and Brown Trout written by Bror Jonsson and published by Springer Science & Business Media. This book was released on 2011-05-03 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Destruction of habitat is the major cause for loss of biodiversity including variation in life history and habitat ecology. Each species and population adapts to its environment, adaptations visible in morphology, ecology, behaviour, physiology and genetics. Here, the authors present the population ecology of Atlantic salmon and brown trout and how it is influenced by the environment in terms of growth, migration, spawning and recruitment. Salmonids appeared as freshwater fish some 50 million years ago. Atlantic salmon and brown trout evolved in the Atlantic basin, Atlantic salmon in North America and Europe, brown trout in Europe, Northern Africa and Western Asia. The species live in small streams as well as large rivers, lakes, estuaries, coastal seas and oceans, with brown trout better adapted to small streams and less well adapted to feeding in the ocean than Atlantic salmon. Smolt and adult sizes and longevity are constrained by habitat conditions of populations spawning in small streams. Feeding, wintering and spawning opportunities influence migratory versus resident lifestyles, while the growth rate influences egg size and number, age at maturity, reproductive success and longevity. Further, early experiences influence later performance. For instance, juvenile behaviour influences adult homing, competition for spawning habitat, partner finding and predator avoidance. The abundance of wild Atlantic salmon populations has declined in recent years; climate change and escaped farmed salmon are major threats. The climate influences through changes in temperature and flow, while escaped farmed salmon do so through ecological competition, interbreeding and the spreading of contagious diseases. The authors pinpoint essential problems and offer suggestions as to how they can be reduced. In this context, population enhancement, habitat restoration and management are also discussed. The text closes with a presentation of what the authors view as major scientific challenges in ecological research on these species.
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.
Download or read book Age Composition Size Migration Timing and Estimation of Smolt to adult Survival of Natural origin Sockeye Salmon Oncorhynchus Nerka in the Wenatchee River WA Watershed 1997 to 2019 written by Braden Judson and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Lake Wenatchee is the dominant producer of Sockeye Salmon (Oncorhynchus nerka) within Washington State, and one of only two self-sustaining populations of Sockeye Salmon within the Columbia River watershed. The Lake Wenatchee Sockeye population is monitored by Chelan Public Utility District, and those data are used to estimate smolt-to-adult returns (SAR) for natural origin Sockeye as an index of marine survival"--Abstract.
Download or read book Early Marine Distribution of Out migrating Juvenile Sockeye Salmon Oncorhynchus Nerka written by Nicole Gerbrandt and published by . This book was released on 2013 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The early marine phase is a critical period for out-migrating juvenile sockeye salmon (Oncorhynchus nerka). They undergo physiological changes while entering into a new environment, and this is thought to be a period of high mortality. This study examined factors affecting swimming depth as juveniles migrated through Rivers Inlet, and compared swimming depth at the point of ocean entry and life history strategies in sockeye salmon from Rivers Inlet and nearby populations on the Central Coast of British Columbia. Most juvenile sockeye salmon swam within two meters of the ocean's surface during their out-migration through Rivers Inlet, and were slightly deeper later in the out-migration. In addition, in a mesocosm experiment, Rivers Inlet juvenile sockeye salmon did not alter their swimming depth in response to increasing salinity at their preferred swimming depth, despite experiencing negative physiological effects when swimming in highly saline waters. Similar data on other nearby sockeye salmon populations were collected. Juvenile sockeye salmon from populations that out-migrate through brackish waters tended to be smaller than individuals from populations that leave fresh water and enter directly into highly saline marine environments, and they too tended swim within the top two to four meters of the surface. This shows that conditions in the top 4 m of the water's surface represent actual conditions experienced by out-migrating juvenile sockeye salmon in the early marine environment and is a critically important observation in terms of understanding such issues as prey availability, the potential role of brackish surface layers in coastal fjords, lagoons and estuaries, and susceptibility to predators. These findings will inform future sampling efforts on these populations, and also suggest that these populations maintain varying life history characteristics which enable them to survive early marine conditions within the top 4 m of the ocean.
Download or read book Geographic Variation in Timing of Fry Emergence and Smolt Migration of Coho Salmon Oncorhynchus Kisutch written by Brian C. Spence and published by . This book was released on 1995 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: The timing of two events in the early life history of coho salmon--emergence from the gravel and entry into the ocean--is presumed to have evolved to ensure maximum survival during these transition periods. Anthropogenic disturbances may disrupt the timing of these events to the detriment of salmon populations. Multivariate analyses were used to examine regional patterns in downstream migration in relation to environmental variation for 50 smolt populations located between central California and southern Alaska. Significant latitudinal gradients were observed in the timing of the peak of migration, duration of migration, and degree of interannual variation in the peak of migration. Smolt migrations of northern populations generally occurred later in the spring, were shorter in duration, and exhibited lower interannual variability in their timing than did those of southern populations. Some variability in these patterns was associated with watershed characteristics (e.g., elevation, distance from ocean); however, latitudinal patterns transcended this variability and may reflect adaptation to differences in temporal "windows of opportunity" in the ocean environments into which smolts enter. Logistic regression models were used to model within- and between-year variation in probability of smolts migrating during 2-d intervals from four streams in Alaska, British Columbia, and Oregon as a function of time interval, lunar periodicity, temperature (absolute, change, cumulative degree days), and streamflow (absolute, change). Migration probability was positively associated with time, temperature, and change in flow, and negatively associated with absolute flow for at least four of the five data sets examined (P
Download or read book An Assessment of the Juvenile Sockeye Salmon Oncorhynchus Nerka Populations of Babine Lake written by Jeremy M. B. Hume and published by Cultus Lake, B.C. : Fisheries and Oceans Canada, Science. This book was released on 2000 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Juvenile sockeye salmon rearing in Babine Lake were re-examined 22 years after the initiation of the Babine Lake Development Project (BLDP). Abundance, distribution, size, and species composition of the limnetic fish populations, including juvenile sockeye salmon, were determined by hydroacoustic and midwater trawl surveys in the autumn of 1993 and the summer and fall of 1994 and 1995 and compared to results collected before and shortly after the start of the BDLP. Our objectives were to look for: 1) changes in the abundance of juvenile sockeye relative to spawning numbers; 2) changes in the utilization of the available nursery area; and 3) the effects of increased popualtion size and density on the size and growth of juvenile sockeye.
Download or read book Effect of Smolt Size and Marine Growth Rates on Adult Sockeye Salmon Oncorhynchus Nerka Returns and Possible Implications for the Cost written by Ryall, Paul J. (Paul James) and published by National Library of Canada. This book was released on 1985 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Linking Freshwater Growth to Size dependent Marine Survival of Sockeye Salmon written by Marta Elizabeth Ree and published by . This book was released on 2019 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the mediating role of body size in determining fitness, the ‘bigger is better’ hypothesis still pervades evolutionary ecology despite evidence that natural selection on phenotypic traits varies in time and space. For Pacific salmon (genus Oncorhynchus), the size at which juveniles migrate to sea (i.e., smolts) has been linked to survival during the early marine period, where larger smolts typically survive at a higher rate than their smaller counterparts. However, the relationship of smolt size and survival becomes more ambiguous when considering confounding factors of age, ocean entry timing, and environmental variability. Despite equivocal results, smolt size appears to be a key trait and therefore changes in freshwater conditions may have consequences for population productivity. Furthermore, due to differences in site-specific habitats, trophic dynamics, and population traits the response of specific populations to these changes is likely to be context specific. The objective of this thesis was to 1) quantify the direction and magnitude of natural selection on smolt size for three age classes of sockeye salmon in a small watershed on Kodiak Island, AK and 2) explore stock-specific effects of temperature and conspecific density on smolt size over a multi-decade time-series to understand historic and possible future trends. To address our first objective, we calculated standardized selection differentials by comparing observed size distributions of out-migrating juvenile salmon to back-calculated smolt length from the scales of surviving, returning adults. Results reveal the magnitude of selection on size was very strong and consistent among years. However, the direction of selection on size consistently varied among age classes. The absolute magnitude of selection was negatively correlated to apparent marine survival and positively correlated to late mean ocean entry timing. To address our second objective, we back-calculated smolt size from returning adult scales to reconstruct a time-series of smolt length of two stocks within a small Alaska watershed on Kodiak Island. Using a dynamic linear model framework, we detected evidence that for one stock, temperature was important in explaining smolt length, and density effects influenced both stocks utilizing the same lakes. Furthermore, forecasts of smolt length showed highly variable responses under scenarios of increasing temperature and high and low densities. Collectively, these results demonstrate that interactions between processes of climate, density, and natural selection are highly context-specific in terms of both inter- and intra- population variability.
