Contribution of Juvenile Estuarine Residency in a Bar-built Estuary to Recruitment of Chinook Salmon (Oncorhynchus Tshawytscha) PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Contribution of Juvenile Estuarine Residency in a Bar-built Estuary to Recruitment of Chinook Salmon (Oncorhynchus Tshawytscha) PDF full book. Access full book title Contribution of Juvenile Estuarine Residency in a Bar-built Estuary to Recruitment of Chinook Salmon (Oncorhynchus Tshawytscha) by Emily Katherine Chen. Download full books in PDF and EPUB format.
Author: Emily Katherine Chen Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 86
Book Description
Estuaries are commonly touted as nurseries for out-migrating salmonids, providing higher prey availability than streams, a physiological transition zone, and refugee from marine predators. Yet the diversity of estuaries makes it difficult to generalize the effect they have on salmonid recruitment. In bar-built estuaries, sandbars form at the mouth of rivers during periods of low flow, closing access to the ocean and disrupting outmigration. In this thesis, I evaluated how residency in a bar-built estuary affects the growth, survival, and ultimately recruitment of Chinook salmon (Oncorhynchus tshawytscha) in Redwood Creek, California. I conducted a mark-recapture experiment on out-migrating juveniles during the summer of 2018 to determine estuary abundance, growth, and survival. I used scales and sagittal otoliths collected from spawning adult carcasses to quantify the contribution of different juvenile life histories to the adult population. I then integrated these data and monitoring data collected from spawning ground surveys, rotary screw traps, and estuary seines to create a stage-structured matrix model. Juveniles that remained in the estuary after the mouth closed were larger at ocean entry than ocean rearing juveniles that entered the ocean earlier in the spring. However, estuary-rearing juveniles grew less and ultimately were smaller than ocean rearing juveniles were prior to winter. Despite having a larger ocean entry size, estuary rearing juveniles had lower survival from river outmigration to adult return than ocean rearing juveniles and contributed disproportionately less to the spawning population. Lack of marine influence and low river flow are common attributes of bar-built estuaries that may lower food availability and deteriorate conditions in these estuaries. Levees constructed in lower Redwood Creek prevent flooding and establishment of marsh and floodplain habitat, potentially majorly limiting the productivity of the estuary and salmonid growth. Restoration efforts designed to address limitations to growth in the estuary such as low food availability and high temperatures are needed to increase the ocean survival and ultimately contribution of estuary juveniles to the population.
Author: Emily Katherine Chen Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 86
Book Description
Estuaries are commonly touted as nurseries for out-migrating salmonids, providing higher prey availability than streams, a physiological transition zone, and refugee from marine predators. Yet the diversity of estuaries makes it difficult to generalize the effect they have on salmonid recruitment. In bar-built estuaries, sandbars form at the mouth of rivers during periods of low flow, closing access to the ocean and disrupting outmigration. In this thesis, I evaluated how residency in a bar-built estuary affects the growth, survival, and ultimately recruitment of Chinook salmon (Oncorhynchus tshawytscha) in Redwood Creek, California. I conducted a mark-recapture experiment on out-migrating juveniles during the summer of 2018 to determine estuary abundance, growth, and survival. I used scales and sagittal otoliths collected from spawning adult carcasses to quantify the contribution of different juvenile life histories to the adult population. I then integrated these data and monitoring data collected from spawning ground surveys, rotary screw traps, and estuary seines to create a stage-structured matrix model. Juveniles that remained in the estuary after the mouth closed were larger at ocean entry than ocean rearing juveniles that entered the ocean earlier in the spring. However, estuary-rearing juveniles grew less and ultimately were smaller than ocean rearing juveniles were prior to winter. Despite having a larger ocean entry size, estuary rearing juveniles had lower survival from river outmigration to adult return than ocean rearing juveniles and contributed disproportionately less to the spawning population. Lack of marine influence and low river flow are common attributes of bar-built estuaries that may lower food availability and deteriorate conditions in these estuaries. Levees constructed in lower Redwood Creek prevent flooding and establishment of marsh and floodplain habitat, potentially majorly limiting the productivity of the estuary and salmonid growth. Restoration efforts designed to address limitations to growth in the estuary such as low food availability and high temperatures are needed to increase the ocean survival and ultimately contribution of estuary juveniles to the population.
Author: Pascale A. L. Goertler Publisher: ISBN: Category : Languages : en Pages : 91
Book Description
For many fish and wildlife species, a mosaic of available habitats is required to complete their life cycle, and is considered necessary to ensure population stability and persistence. Particularly for young animals, nursery habitats provide opportunities for rapid growth and high survival during this vulnerable life stage. My thesis focuses on juvenile Chinook salmon (Oncorhynchus tshawytscha) and their use of estuarine wetlands as nursery habitat. Estuaries are highly productive systems representing a mosaic of habitats connecting rivers to the sea, and freshwater tidal estuaries provide abundant prey communities, shade, refuge from predation and transitional habitat for the osmoregulatory changes experienced by anadromous fishes. I will be discussing the freshwater tidal wetland habitat use of juvenile Chinook salmon in the Columbia River estuary, which are listed under the Endangered Species Act. I used otolith microstructural growth estimates and prey consumption to measure rearing habitat quality. This sampling effort was designed to target as much genetic diversity as possible, and individual assignment to regional stocks of origin was used to describe the diversity of juvenile Chinook salmon groups inhabiting the estuary. Diversity is important for resilience, and in salmon biocomplexity within fish stocks has been shown to ensure collective productivity despite environmental change. However much of the research which links diversity to resilience in salmon has focused on the adult portion of the life cycle and many resource management policies oversimplify juvenile life history diversity. When this oversimplification of juvenile life history diversity is applied to salmon conservation it may be ignoring critical indicators for stability. Therefore in addition to genetic diversity I also explore methods for better defining juvenile life history diversity and its application in salmon management, such as permitting requirements, habitat restoration, hydropower practices and hatchery management. This study addresses how juvenile salmon growth changes among a range of wetland habitats in the freshwater tidal portion of the Columbia River estuary and how growth variation describes and contributes to life history diversity. To do this, I incorporated otolith microstructure, individual assignment to regional stock of origin, GIS habitat mapping and diet composition, in three habitats (mainstem river, tributary confluence and backwater channel) along ~130 km of the upper estuary. For my first chapter I employed a generalized linear model (GLM) to test three hypotheses: juvenile Chinook growth was best explained by (1) temporal factors, (2) habitat use, or (3) demographic characteristics, such as stock of origin or the timing of seaward migration. I found that variation in growth was best explained by habitat type and an interaction between fork length and month of capture. Juvenile Chinook salmon grew faster in backwater channel habitat and later in the summer. I also found that mid-summer and late summer/fall subyearlings had the highest estuarine growth rates. When compared to other studies in the basin these juvenile Chinook grew on average 0.23, 0.11-0.43 mm/d in the freshwater tidal estuary, similar to estimates in the brackish estuary, but ~4 times slower than those in the plume and upstream reservoirs. However, survival studies from the system elucidated a possible tradeoff between growth and survival in the Columbia River basin. These findings present a unique example of the complexity in understanding the influences of the many processes that generate variation in growth rate for juvenile anadromous fish inhabiting estuaries. In my second chapter, I used otolith microstructure and growth trends produced in a dynamic factor analysis (DFA, a multivariate time series method only recently being used in fisheries) to identify the life history variation in juvenile Chinook salmon caught in the Columbia River estuary over a two-year period (2010-2012). I used genetic assignment to stock of origin and capture location and date with growth trajectories, as a proxy for habitat transitions, to reconstruct life history types. DFA estimated four to five growth trends were present in juvenile Chinook salmon caught in the Columbia River estuary, diversity currently being simplified in many management practices. Regional stocks and habitats did not display divergent growth histories, but the marked hatchery fish did ordinate very similarly in the trend loadings from the DFA analysis, suggesting that hatchery fish may not experience the same breadth of growth variability as wild fish. I was not able to quantify juvenile life history diversity, and juvenile Chinook life history diversity remains difficult to catalog and integrate into species conservation and habitat restoration for resource management. However, by expanding our understanding of how juvenile Chinook salmon experience their freshwater rearing environment we improve our capacity to conserve and manage salmon populations. The findings from my thesis provide the necessary information for a restoration framework to link habitat features with salmon management goals, such as juvenile growth, wild and genetic origin and life history diversity.
Author: Lance A. Campbell Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 210
Book Description
Despite evidence that juvenile Chinook salmon (Oncorhynchus tshawytscha) utilize North Pacific estuaries for growth and salinity acclimation, research in the Columbia River estuary has lead to opposing hypotheses about the estuary's importance as a salmon rearing environment. Many contemporary tagging studies indicate that salmon residency within the estuary is short (
Author: Publisher: ISBN: Category : Languages : en Pages : 45
Book Description
Presents an analysis of juvenile salmon population growth and abundance data collected in the Campbell River estuary in 1994 to describe chinook habitat use, residency timing, growth, and potential competitive interactions between wild chinook fry, hatchery chinook, and other salmon species. Results are compared with previous information on habitat use, residence timing, and growth of wild and hatchery chinook. Analyses are presented in five parts: use of a discriminant function to predict the origin of chinook juveniles whose origin could not be field-determined; estimation of density and biomass of juvenile salmon in the estuary and a comparison of habitat use and residence timing; calculation of growth rates for wild and hatchery chinook; prediction of wild chinook fry weight based on total salmon biomass; and estimation of the carrying capacity of the estuary for juvenile chinook, coho, and all salmon species combined, based on mark-recapture and escapement-biostandard methods.
Author: Crystal R. Hackmann Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 184
Book Description
Estuaries provide juvenile salmonids with highly productive feeding grounds, refugia from tidal fluctuations and predators, and acclimation areas for smoltification. However, these dynamic, fluctuating salinity environments may also be physiologically stressful to growing juvenile fish. In order to evaluate the costs and benefits of estuarine marshes to juvenile Chinook salmon, I observed habitat use, diet, and growth of fish in the Nehalem Estuary on the Oregon coast. I also examined physiological costs associated with salmon living in fluctuating salinities and growth rates in laboratory experiments. I collected growth, diet and osmoregulation information from juvenile Chinook salmon in three tidal marsh sites in the Nehalem Bay and from juveniles in the Nehalem River. Stomach contents indicated that a high proportion of the diet is derived from terrestrial prey. These allochthonous prey resources likely become available during the flood stages of tidal cycles when drift, emergent and terrestrial insects would become available from the grasses surrounding the water. This field study confirmed that juvenile Chinook salmon utilized fluctuating salinity habitats to feed on a wide range of items including terrestrial-derived resources. Although field studies indicate that fish in estuarine habitats grow well and have access to quality prey resources, experimental manipulations of salinities were used to quantify the physiological costs of residing in the freshwater-saltwater transitional zone. In the laboratory, I designed an experiment to investigate the physiological responses to fluctuating salinities. Experimental treatments consisted of freshwater (FW), saltwater (SW) (22-25%o); and a fluctuating salinity (SW/FW) (2 - 25%o). These treatments were based on typical salinity fluctuations found in estuarine habitats. I measured length, weight, plasma electrolytes and cortisol concentrations for indications of growth and osmoregulatory function. The fluctuating salinity treatment had a negative effect on growth rate and initial osmoregulatory ability when compared with constant freshwater and saltwater treatments. The results indicated that fluctuating salinities had a small but marginally significant reduction in growth rate, possibly due to the additional energetic requirements of switching between hyper- and hypo-osmoregulation. However, 24-hour saltwater challenge results indicated that all fish were capable of osmoregulating in full-strength seawater. In a second experiment, I manipulated feed consumption rates of juvenile spring Chinook salmon to investigate the effects of variable growth rates on osmoregulatory ability and to test the validity of RNA:DNA ratios as indication of recent growth. The treatments consisted of three different feeding rates: three tanks of fish fed 0.7 5% (LOW) body weight; three tanks fed 3% (HIGH) body weight; and three tanks were fasted (NONE) during the experiment. These laboratory results showed a significant difference in the osmoregulatory ability of the NONE treatment compared to the LOW and HIGH treatments which indicates that a reduction in caloric intake significantly effected osmoregulatory capabilities during a 24 hour saltwater challenge. Furthermore, this suggests that there is a minimum energetic requirement in order to maintain proper ion- and osmoregulation in marine conditions. Estuarine marshes have the potential to provide productive feeding grounds with sufficient prey input from terrestrial systems. However, utilization of these marshes in sub-optimal conditions could alter behavior or impair physiological condition of juvenile Chinook salmon prior to their seaward migration by providing insufficient prey resources in a potentially stressful, fluctuating environment. Therefore, the physiological costs associated with estuarine habitat use should be well understood in order to aid future restoration planning.
Author: Melanie Jeanne Davis Publisher: ISBN: Category : Languages : en Pages : 228
Book Description
A complex mosaic of estuarine habitats is postulated to bolster the growth and survival of juvenile Chinook salmon by diversifying the availability and configuration of prey and refugia. Consequently, efforts are underway along the North American Pacific Coast to return modified coastal ecosystems to historical or near-historical conditions, but restoring habitats are often more sensitive to anthropogenic or climate-mediated disturbance than relict (unaltered) habitats. Estuaries are expected to experience longer inundation durations as sea-levels rise, leading to reductions in intertidal emergent marshes, mudflats, and eelgrass beds. Furthermore, rising ocean temperatures may have metabolic consequences for fall-run populations of Chinook salmon, which tend to out-migrate during the spring and summer. Extensive monitoring programs have allowed managers to assess the initial benefits of management efforts (including restoration) for juvenile salmon at local and regional scales, but at present they have limited options for predicting and responding to the concurrent effects of climate change in restoring and relict coastal ecosystems. For my dissertation I addressed this gap in knowledge using a comprehensive monitoring dataset from the restoring Nisqually River Delta in southern Puget Sound, Washington. I focused on the following questions: 1) How do juvenile Chinook salmon prey consumption and dietary energy density vary throughout a mosaic of estuarine habitats, and is this variation related to differences in physiological condition? 2) How do among-habitat differences in thermal regime and prey consumption affect the bioenergetic growth potential of juvenile Chinook salmon? 3) How will shifts in the estuarine habitat mosaic vary under different sea-level rise and management scenarios? and 4) How will these climate- and management-mediated shifts in the estuarine habitat mosaic impact habitat quality for juvenile Chinook salmon? To address the first question, I used stomach content and stable isotope analyses to analyze the diets of wild and hatchery Chinook salmon captured in different estuarine habitats during the out-migration season (March-July of 2014 and 2015). I also linked measures of stomach fullness and dietary energy density to body condition. To address the second question, I used a bioenergetics model to determine how among-habitat differences in water temperature and diet might affect juvenile Chinook salmon growth. To address the third question, I designed and calibrated a marsh accretion model and decision support tool using post-restoration monitoring data sets and spatial coverages. Finally, to address the fourth question, I combined output from the marsh accretion model, a hydrological model, and measurements of prey availability into a spatially explicit version of the bioenergetics model to assess the habitat quality and growth rate potential of the entire estuarine habitat mosaic under different sea-level rise and management scenarios. When considered in tandem, these chapters represent a novel approach to habitat management. Assessments of juvenile salmon diet and physiology, marsh accretion models, and bioenergetics models have been independently implemented along the Pacific Coast, but the amalgamation of all three approaches into a single, spatially explicit analysis represents a novel and significant contribution to the scientific literature. In conducting these analyses for the Nisqually River Delta, some major themes emerged regarding the importance and vulnerability of specific habitats. An integrative diet analysis using stomach contents and stable isotopes found distinct dietary niches between wild and hatchery Chinook salmon. Wild fish were more likely to utilize the freshwater tidal forested and transitional brackish marsh habitats along the main stem river, where energy-rich insect drift made up most of their dietary biomass. The availability and consumption of insect prey resulted in distinct benefits to body condition and growth, as determined by direct physiological measurements and output from the habitat-specific bioenergetics model. These findings highlight the importance of freshwater and brackish emergent marsh habitats with overhanging vegetation, which can regulate water temperatures and supply insect drift. Unfortunately, freshwater tidal forests, brackish marshes, and low and high elevation emergent salt marshes are highly vulnerable to sea-level rise, especially when geological and anthropogenic features limit sediment accretion or lateral expansion. When spatial layers from the marsh accretion model were incorporated into the spatially explicit version of the bioenergetics model, output indicated that loss of low and high salt marsh reduced the amount of prey available for juvenile salmon, thus decreasing modeled growth rate potential. In all, these findings highlight the importance of preserving the estuarine habitat mosaic for out-migrating juvenile salmon, especially as tidal regimes and ocean temperatures continue to shift through time.
Author: David K. Hering Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 300
Book Description
Tidal wetland channels provide rearing habitat for juvenile Chinook salmon as they emigrate from freshwater habitat and prepare to enter the ocean. Widespread diking and drainage of estuarine marshes for agricultural and urban development may have contributed to a decline in salmon abundance in the Pacific Northwest, prompting efforts to restore estuarine salmon habitat in the region. I investigated the growth and residence patterns of age-0 Chinook salmon in two blind tidal channels in the Salmon River estuary, Oregon. One channel drained a natural high salt marsh in "reference" condition, and the other channel was in an adjacent salt marsh, restored to tidal inundation in 1996 after being diked and controlled by a tide gate for thirty five years. Recapture of individually marked fish indicated salmon growth rates were similar in the two channels, though growth rates varied more seasonally in the restored site. Average minimum residence times of individual fish were approximately ten days in each channel, and individual salmon were observed up to 79 and 117 days after initial marking in the reference and restored channels, respectively. To characterize movement of age-0 salmon within tidal channels, I tested the feasibility of stationary Passive Integrated Transponder (PIT) detection within a small (approximately 8m wide) tidal channel within the natural marsh system. I found that a stationary PIT detector was an effective tool for monitoring tagged fish movement in a brackish water channel network. Salmon movements in the channel were asymmetrical about high slack tide, with peak movement frequency occurring late during both flood and ebb tide periods. Most movements were in the direction of tidal currents, but 20% of individuals entered the channel against the ebbing tide. Individuals occupied the intertidal channel for a median 4.9 hours and as long as 8.9 hours per tidal cycle, and few were detected moving when water depth was
Author: Aaron David Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 105
Book Description
During the transition of juveniles from fresh water to estuarine and coastal environments, the survival of Pacific salmon (Oncorhynchus spp.) can be strongly size-selective and cohort abundance is partly determined. Because the quantity and quality of food consumed influence juvenile salmon growth, high rates of prey and energy acquisition during estuarine residence are important for survival. Human activities may have affected the foraging performance of juvenile salmon in estuaries by reducing the area of wetlands and by altering the abundance of conspecifics. To improve our understanding of the effects of wetland loss and conspecific density on juvenile salmon foraging performance and diet composition in estuaries, I assembled Chinook salmon (O. tshawytscha) diet and density data from nine U.S. Pacific Northwest estuaries across a gradient of wetland loss. We evaluated the influence of wetland loss and conspecific density on juvenile Chinook salmon instantaneous ration and energy ration, two measures of foraging performance, and whether the effect of density varied among estuaries with different levels of wetland loss. We also assessed the influence of wetland loss and three other covariates on salmon diet composition. There was no evidence of a direct effect of wetland loss on juvenile salmon foraging performance, but wetland loss mediated the effect of conspecific density on salmon foraging performance and altered salmon diet composition. These results suggest that habitat loss can interact with conspecific density to constrain the foraging performance of juvenile fishes, and ultimately their growth, during a life-history stage when survival is positively correlated with growth and size. I also evaluated whether restoring tidal flow to previously diked estuarine wetlands also restores foraging and growth opportunities for juvenile Chinook salmon. Several studies have assessed the value of restored tidal wetlands for juvenile salmon, but few have used integrative measures of salmon physiological performance, such as habitat-specific growth potential, to evaluate restoration. Our study took place in the Nisqually River delta, where recent dike removals restored tidal flow to 364 ha of marsh, the largest tidal marsh restoration in the Pacific Northwest. To compare Chinook salmon foraging performance and growth potential in two restored and two reference marshes over three years post-restoration, we sampled fish assemblages, water temperatures, and juvenile Chinook salmon diet composition and consumption rates, and used these data as inputs to a bioenergetics model. We found that juvenile Chinook salmon foraging performance and growth potential were similar between the restored and reference marshes. However, densities of Chinook salmon were significantly lower in the restored marshes and growth potential was more variable in the restored marshes due to their more variable and warmer (2?? C) water temperatures compared to the reference marshes. These results indicate that some but not all ecosystem attributes that are important to juvenile salmon rapidly recover following large-scale tidal marsh restoration.
Author: Emily Katherine Chen
Author: Emily Katherine Chen
Author: David Zajanc
Author: Pascale A. L. Goertler
Author: Lance A. Campbell
Author: 
Author: Crystal R. Hackmann
Author: Melanie Jeanne Davis
Author: A. Keith Taniguchi
Author: David K. Hering
Author: Aaron David