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BackgroundConsiderable resources are spent to track fish movement in marine environments, often with the intent of estimating behavior, distribution, and abundance. Resulting data from these monitoring efforts, including tagging studies and genetic sampling, often can be siloed. For Pacific salmon in the Northeast Pacific Ocean, predominant data sources for fish monitoring are coded wire tags (CWTs) and genetic stock identification (GSI). Despite their complementary strengths and weaknesses in coverage and information content, the two data streams rarely have been integrated to inform Pacific salmon biology and management. Joint, or integrated, models can combine and contextualize multiple data sources in a single statistical framework to produce more robust estimates of fish populations.MethodsWe introduce and fit a comprehensive joint model that integrates data from CWT recoveries and GSI sampling to inform the marine life history of Chinook salmon stocks at spatial and temporal scales relevant to ongoing fisheries management efforts. In a departure from similar models based primarily on CWT recoveries, modeled stocks in the new framework encompass both hatchery- and natural-origin fish. We specifically model the spatial distribution and marine abundance of four distinct stocks with spawning locations in California and southern Oregon, one of which is listed under the U.S. Endangered Species Act.ResultsUsing the joint model, we generated the most comprehensive estimates of marine distribution to date for all modeled Chinook salmon stocks, including historically data poor and low abundance stocks. Estimated marine distributions from the joint model were broadly similar to estimates from a simpler, CWT-only model but did suggest some differences in distribution in select seasons. Model output also included novel stock-, year-, and season-specific estimates of marine abundance. We observed and partially addressed several challenges in model convergence with the use o

Variation in life-history traits within and across species is known to reflect adaptations to different environmental drivers through a diversity of mechanisms. Trait variation can also help buffer species and populations against extinction in fluctuating environments and against anthropogenic disturbances. This recognition has led to a growing interest in applying evolutionary principles to inform eco- logical restoration actions. In this dissertation, I explored how widespread variation in migratory life-histories in Pacific salmonids (Oncorhynchus spp.) is driven by a suite of environmental factors with the goals of shedding light on what drives the frequency of these migratory strategies and creating a restoration framework to aid in the restoration of these imperiled species. In Chapter 1, I examined how anthropogenic disturbance in the form of stream modification influences the frequency of anadromy in steelhead (O. mykiss) across California. I found that with an increasing number of instream barriers, the frequency of anadromy was reduced. I then developed an evolutionary restoration framework to guide managers and encourage broader consideration of in situ evolution during the development of habitat restoration projects. In Chapter 2, I quantified distinct juvenile migratory strategies of Chinook salmon (O. tshawytscha) and modeled the environmental drivers that influence their frequency. I found two distinct migratory strategies were widespread across these populations and their frequencies were driven a juvenile density, rearing habitat, and flow. In Chapter 3, I examined what environmental and demographic factors influenced spring juvenile migratory strategies in coastal coho salmon (O. kisutch). I found that juvenile density, flow, and latitude are strong drivers of these migratory behaviors. As in Chinook salmon, a density-dependent mechanism also appears to operate in coho salmon populations, suggesting a form of bet-hedging might be common across out

Variation in life-history traits within and across species is known to reflect adaptations to different environmental drivers through a diversity of mechanisms. Trait variation can also help buffer species and populations against extinction in fluctuating environments and against anthropogenic disturbances. This recognition has led to a growing interest in applying evolutionary principles to inform eco- logical restoration actions. In this dissertation, I explored how widespread variation in migratory life-histories in Pacific salmonids (Oncorhynchus spp.) is driven by a suite of environmental factors with the goals of shedding light on what drives the frequency of these migratory strategies and creating a restoration framework to aid in the restoration of these imperiled species. In Chapter 1, I examined how anthropogenic disturbance in the form of stream modification influences the frequency of anadromy in steelhead (O. mykiss) across California. I found that with an increasing number of instream barriers, the frequency of anadromy was reduced. I then developed an evolutionary restoration framework to guide managers and encourage broader consideration of in situ evolution during the development of habitat restoration projects. In Chapter 2, I quantified distinct juvenile migratory strategies of Chinook salmon (O. tshawytscha) and modeled the environmental drivers that influence their frequency. I found two distinct migratory strategies were widespread across these populations and their frequencies were driven a juvenile density, rearing habitat, and flow. In Chapter 3, I examined what environmental and demographic factors influenced spring juvenile migratory strategies in coastal coho salmon (O. kisutch). I found that juvenile density, flow, and latitude are strong drivers of these migratory behaviors. As in Chinook salmon, a density-dependent mechanism also appears to operate in coho salmon populations, suggesting a form of bet-hedging might be common across out

Variation in life-history traits within and across species is known to reflect adaptations to different environmental drivers through a diversity of mechanisms. Trait variation can also help buffer species and populations against extinction in fluctuating environments and against anthropogenic disturbances. This recognition has led to a growing interest in applying evolutionary principles to inform eco- logical restoration actions. In this dissertation, I explored how widespread variation in migratory life-histories in Pacific salmonids (Oncorhynchus spp.) is driven by a suite of environmental factors with the goals of shedding light on what drives the frequency of these migratory strategies and creating a restoration framework to aid in the restoration of these imperiled species. In Chapter 1, I examined how anthropogenic disturbance in the form of stream modification influences the frequency of anadromy in steelhead (O. mykiss) across California. I found that with an increasing number of instream barriers, the frequency of anadromy was reduced. I then developed an evolutionary restoration framework to guide managers and encourage broader consideration of in situ evolution during the development of habitat restoration projects. In Chapter 2, I quantified distinct juvenile migratory strategies of Chinook salmon (O. tshawytscha) and modeled the environmental drivers that influence their frequency. I found two distinct migratory strategies were widespread across these populations and their frequencies were driven a juvenile density, rearing habitat, and flow. In Chapter 3, I examined what environmental and demographic factors influenced spring juvenile migratory strategies in coastal coho salmon (O. kisutch). I found that juvenile density, flow, and latitude are strong drivers of these migratory behaviors. As in Chinook salmon, a density-dependent mechanism also appears to operate in coho salmon populations, suggesting a form of bet-hedging might be common across out

Species status statement for the Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus).

Species status statement for the Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus).

In this dissertation I investigate the impacts of artificial and natural watershed disconnection on the management and ecology of valued native California fishes. I explore the subject at regional and local scales and pay particular attention to the consequences of river discontinua on juvenile rearing and habitat use patterns for multiple populations of Pacific salmonids with conservation and economic importance. Scientific inquiry in my study systems was initially motivated by the intention to comprehend the potential direct and indirect links between connectivity loss and collapsed hatchery-supported Chinook salmon (Oncorhynchus tshawytscha) commercial and recreational fisheries and recurring widespread animal mass mortality events involving the take of threatened O. mykiss at one of California's few remaining estuary-saltmarsh habitat complexes. My research coincided with a severe and historic drought and the timing offers a special opportunity to better understand the potential effects of climate change on salmon hatchery management and estuarine fish ecology in California. From the 1940s to the 1970s, salmon hatcheries were constructed in the foothill zones of California's Sacramento and San Joaquin river watersheds in order to mitigate for lost spawning and rearing habitat upstream of large impassable dams. While initially intended to reduce harvesting pressure on wild stocks, hatchery-produced Central Valley fall run Chinook salmon (CVFRCS) now dominate the population complex and comprise the majority of the California and Southern Oregon commercial salmon fishery. The population collapsed from 2006-2009 and the commercial and recreational fisheries were completely closed in 2007 and 2008 for the first time in their 90 year histories. The proximate cause for the collapse was warm water temperatures and low food abundances in the nearshore zone when smolts exited the Golden Gate in 2005. However, the environmental conditions were not unprecedented and, given

In this dissertation I investigate the impacts of artificial and natural watershed disconnection on the management and ecology of valued native California fishes. I explore the subject at regional and local scales and pay particular attention to the consequences of river discontinua on juvenile rearing and habitat use patterns for multiple populations of Pacific salmonids with conservation and economic importance. Scientific inquiry in my study systems was initially motivated by the intention to comprehend the potential direct and indirect links between connectivity loss and collapsed hatchery-supported Chinook salmon (Oncorhynchus tshawytscha) commercial and recreational fisheries and recurring widespread animal mass mortality events involving the take of threatened O. mykiss at one of California's few remaining estuary-saltmarsh habitat complexes. My research coincided with a severe and historic drought and the timing offers a special opportunity to better understand the potential effects of climate change on salmon hatchery management and estuarine fish ecology in California. From the 1940s to the 1970s, salmon hatcheries were constructed in the foothill zones of California's Sacramento and San Joaquin river watersheds in order to mitigate for lost spawning and rearing habitat upstream of large impassable dams. While initially intended to reduce harvesting pressure on wild stocks, hatchery-produced Central Valley fall run Chinook salmon (CVFRCS) now dominate the population complex and comprise the majority of the California and Southern Oregon commercial salmon fishery. The population collapsed from 2006-2009 and the commercial and recreational fisheries were completely closed in 2007 and 2008 for the first time in their 90 year histories. The proximate cause for the collapse was warm water temperatures and low food abundances in the nearshore zone when smolts exited the Golden Gate in 2005. However, the environmental conditions were not unprecedented and, given

Vertical migration is the most widespread migration in the aquatic world, yet the mechanisms limiting the extent of this behavior are largely unknown. In the Baltic Sea, some Atlantic cod Gadus morhua perform vertical foraging migrations into severely hypoxic demersal zones where aerobic metabolism is insufficient to cover energy requirements. After foraging, the fish return to better oxygenated waters for physiological recovery and digestion. To test the influence of phenotypic variation in aerobic scope (AS; the difference between the maximum and the minimum metabolic rate) on the capacity to migrate into severely hypoxic zones, we incorporated AS into a state-dependent individual-based model simulating vertical foraging migrations of G. morhua. We found little effect of individual variation in AS on the capacity for vertical migration when the zone used for physiological recovery was normoxic. In contrast, when there was moderate hypoxia (30% air saturation, O-2sat) in the zone used for physiological recovery, the high AS phenotype had a clear advantage because it could forage 3-4 times longer in the severely hypoxic (16% O-2sat, i.e. below the threshold for aerobic metabolism of the species) demersal zone compared to the low AS phenotype. Thus, phenotypic variation in AS is only important when there is moderate hypoxia in the zone used for physiological recovery, suggesting that the influence of AS variation on the capacity for vertical migration is context dependent. We propose that elevated AS may be evolutionarily favorable when hypoxia prevails in the water column.

Fish assemblages in relation to environmental variables within the Broederstroom and Debengeni Rivers were investigated. Both rivers were characterized by coarse substrates (pebble and gravel), temperatures below 20°C and moderate depth. Trout dominated fish assemblages in terms of numbers caught and was only distributed at higher altitude sites >1400 m (a.s.l). Coarse substrates, temperatures below 15°C, flow rate, depth and riparian cover were the variables shown important for the distribution of trout by multivariate analysis. The confinement of the trout to higher altitude and lack of optimal habitat variables at lower altitude sites contributed to the assertion that the area is marginal for trout distribution. It was therefore inferred that the marginality of the area is the possible explanation for trout failure to self-sustain its population, therefore dependent on the continuous restocks by the local hatchery. The continuous restocks of small size trout in the Broederstroom River prompted a subsequent study where trout’s impact on macroinvertebrate communities was evaluated through surveys and field experiments. The ability of small trout to utilize macroinvertebrates made them suitable candidates to evaluating their impact in the area. Aquatic invertebrates were found to be the main food source for the trout in the area. Taxa such as Gomphidae and Potamonautidae were the most frequent food items from the analyzed stomachs of trout. However, observations from both field surveys and experiments showed that trout is a weak regulator of macroinvertebrate diversity in the area, since there were no significant differences (ANOVA, P<0.05) in the diversity of invertebrates from trout invaded and uninvaded sites. Trout being a weak regulator of macroinvertebrate diversity in the area, it prompted surveys to the Ebenezer Dam to determine its competitive interactions with native predatory species. If the introduced species is a more efficient predator than the native

Understanding factors influencing survival of Pacific salmonids (Oncorhynchus spp.) is essential to species conservation, because drivers of mortality can vary over multiple spatial and temporal scales. Although recent studies have evaluated the effects of climate, habitat quality, or resource management (e.g., hatchery operations) on salmonid recruitment and survival, a failure to look at multiple factors simultaneously leaves open questions about the relative importance of different factors. We analyzed the relationship between ten factors and survival (1980-2007) of four populations of salmonids with distinct life histories from two adjacent watersheds (Salmon and Scott rivers) in the Klamath River basin, California. The factors were ocean abundance, ocean harvest, hatchery releases, hatchery returns, Pacific Decadal Oscillation, North Pacific Gyre Oscillation, El Niño Southern Oscillation, snow depth, flow, and watershed disturbance. Permutation tests and linear mixed-effects models tested effects of factors on survival of each taxon. Potential factors affecting survival differed among taxa and between locations. Fall Chinook salmon O. tshawytscha survival trends appeared to be driven partially or entirely by hatchery practices. Trends in three taxa (Salmon River spring Chinook salmon, Scott River fall Chinook salmon; Salmon River summer steelhead trout O. mykiss) were also likely driven by factors subject to climatic forcing (ocean abundance, summer flow). Our findings underscore the importance of multiple factors in simultaneously driving population trends in widespread species such as anadromous salmonids. They also show that the suite of factors may differ among different taxa in the same location as well as among populations of the same taxa in different watersheds. In the Klamath basin, hatchery practices need to be reevaluated to protect wild salmonids.

Perhaps one of the world's most important groups of fish are the species within the Pacific trout complex, due to their harvest in fisheries and use in aquaculture. This dissertation consists of an in-depth evaluation of this group at different scales, from the assessment of biological traits throughout the reconstruction of pedigrees in two populations to a phylogeographic examination of multiple largely undescribed species. Here, a combination of novel molecular techniques allowed me to address critical ecological questions for the management and conservation of this group.In chapter one, I describe the discovery, characterization and development of single nucleotide polymorphisms for O. mykiss for the study of ecological interactions, phylogeography, and conservation status. These tools have great power for population genetic analysis, and for individual identification and pedigree reconstruction. The last allows the tracking of families, and an unprecedented level of evaluation of natural and hatchery populations.Chapter two expands the scope of these molecular tools to provide a powerful means of understanding of biological traits for steelhead hatchery programs in the Russian River, California. Reconstruction of cohort age distributions revealed a strong component of fish that spawn at age two, in contrast to program goals and distinct from naturally spawning steelhead. Correlations between family members in the day of spawning revealed a strongly heritable component to this life history trait and demonstrated the potential for selection to alter life history traits. These results demonstrate the promise of SNP-based pedigree reconstruction for providing biological inference in high-fecundity organisms.Chapter three describes how the molecular tools developed were applied to population genetics of trout inhabiting northwestern Mexico, to elucidate biodiversity, and evolutionary history, and measure introgression from hatchery rainbow trout. Here, I confirmed t

Dam removal is a new and rapidly growing phenomenon that is reshaping watersheds across the United States; nearly 600 dams were removed from American rivers 1999-2012. Dam removal restores natural flows of water, material, and wildlife upstream, downstream, and out across the floodplain. Despite this massive restorative impact, it is politically controversial, reshaping familiar landscapes and challenging traditional economies and the communities that depended upon them. American dams are aging - 85% of them will be past their useful lives by 2020 - and it is likely that many more will be removed in the future. In this work, I examine the politics of dam removal as well as its impacts on rivers, performing case studies of three major dam removals in one of the United States' removal hotspots, the West Coast. The primary restoration target in this region is populations of Pacific salmon and sea-going trout (genus Oncorhynchus), which were historically enormous but are now largely endangered.The 47-foot Marmot Dam was removed from Oregon's Sandy River in 2007, the 39-foot Savage Rapids Dam came out of Oregon's Rogue River in 2009, and the Elwha/Glines Canyon complex, 105 and 210 feet tall, started to be removed from the Elwha River, Washington, in 2011. Each of these dams was functional and economically productive when it was removed. I analyzed the political frames, venue shopping, and advocacy coalition dynamics of each case. In each case, the most challenging political frame was the cultural role of the dam and reservoir, which had long provided ancillary recreational and scenic benefits to the public - the community saw the artificial lake as their natural landscape. The policy subsystem governing dam removal is broad and evolving, so stakeholders found useful political venues in many places. Ultimately, it was necessary for each group of stakeholders to form a mega-coalition, wherein nearly every interest group worked together to seek a united solution. It was ne

Dam removal is a new and rapidly growing phenomenon that is reshaping watersheds across the United States; nearly 600 dams were removed from American rivers 1999-2012. Dam removal restores natural flows of water, material, and wildlife upstream, downstream, and out across the floodplain. Despite this massive restorative impact, it is politically controversial, reshaping familiar landscapes and challenging traditional economies and the communities that depended upon them. American dams are aging - 85% of them will be past their useful lives by 2020 - and it is likely that many more will be removed in the future. In this work, I examine the politics of dam removal as well as its impacts on rivers, performing case studies of three major dam removals in one of the United States' removal hotspots, the West Coast. The primary restoration target in this region is populations of Pacific salmon and sea-going trout (genus Oncorhynchus), which were historically enormous but are now largely endangered.The 47-foot Marmot Dam was removed from Oregon's Sandy River in 2007, the 39-foot Savage Rapids Dam came out of Oregon's Rogue River in 2009, and the Elwha/Glines Canyon complex, 105 and 210 feet tall, started to be removed from the Elwha River, Washington, in 2011. Each of these dams was functional and economically productive when it was removed. I analyzed the political frames, venue shopping, and advocacy coalition dynamics of each case. In each case, the most challenging political frame was the cultural role of the dam and reservoir, which had long provided ancillary recreational and scenic benefits to the public - the community saw the artificial lake as their natural landscape. The policy subsystem governing dam removal is broad and evolving, so stakeholders found useful political venues in many places. Ultimately, it was necessary for each group of stakeholders to form a mega-coalition, wherein nearly every interest group worked together to seek a united solution. It was ne

Perhaps one of the world's most important groups of fish are the species within the Pacific trout complex, due to their harvest in fisheries and use in aquaculture. This dissertation consists of an in-depth evaluation of this group at different scales, from the assessment of biological traits throughout the reconstruction of pedigrees in two populations to a phylogeographic examination of multiple largely undescribed species. Here, a combination of novel molecular techniques allowed me to address critical ecological questions for the management and conservation of this group.In chapter one, I describe the discovery, characterization and development of single nucleotide polymorphisms for O. mykiss for the study of ecological interactions, phylogeography, and conservation status. These tools have great power for population genetic analysis, and for individual identification and pedigree reconstruction. The last allows the tracking of families, and an unprecedented level of evaluation of natural and hatchery populations.Chapter two expands the scope of these molecular tools to provide a powerful means of understanding of biological traits for steelhead hatchery programs in the Russian River, California. Reconstruction of cohort age distributions revealed a strong component of fish that spawn at age two, in contrast to program goals and distinct from naturally spawning steelhead. Correlations between family members in the day of spawning revealed a strongly heritable component to this life history trait and demonstrated the potential for selection to alter life history traits. These results demonstrate the promise of SNP-based pedigree reconstruction for providing biological inference in high-fecundity organisms.Chapter three describes how the molecular tools developed were applied to population genetics of trout inhabiting northwestern Mexico, to elucidate biodiversity, and evolutionary history, and measure introgression from hatchery rainbow trout. Here, I confirmed t

Understanding factors influencing survival of Pacific salmonids (Oncorhynchus spp.) is essential to species conservation, because drivers of mortality can vary over multiple spatial and temporal scales. Although recent studies have evaluated the effects of climate, habitat quality, or resource management (e.g., hatchery operations) on salmonid recruitment and survival, a failure to look at multiple factors simultaneously leaves open questions about the relative importance of different factors. We analyzed the relationship between ten factors and survival (1980-2007) of four populations of salmonids with distinct life histories from two adjacent watersheds (Salmon and Scott rivers) in the Klamath River basin, California. The factors were ocean abundance, ocean harvest, hatchery releases, hatchery returns, Pacific Decadal Oscillation, North Pacific Gyre Oscillation, El Niño Southern Oscillation, snow depth, flow, and watershed disturbance. Permutation tests and linear mixed-effects models tested effects of factors on survival of each taxon. Potential factors affecting survival differed among taxa and between locations. Fall Chinook salmon O. tshawytscha survival trends appeared to be driven partially or entirely by hatchery practices. Trends in three taxa (Salmon River spring Chinook salmon, Scott River fall Chinook salmon; Salmon River summer steelhead trout O. mykiss) were also likely driven by factors subject to climatic forcing (ocean abundance, summer flow). Our findings underscore the importance of multiple factors in simultaneously driving population trends in widespread species such as anadromous salmonids. They also show that the suite of factors may differ among different taxa in the same location as well as among populations of the same taxa in different watersheds. In the Klamath basin, hatchery practices need to be reevaluated to protect wild salmonids.

Artificial propagation strategies often incur selection in captivity that leads to traits that are maladaptive in the wild. For propagation programs focused on production rather than demographic contribution to wild populations, effects on wild populations can occur through unintentional escapement or the need to release individuals into natural environments for part of their life cycle. In this case, 2 alternative management strategies might reduce unintended fitness consequences on natural populations: (1) reduce selection in captivity as much as possible to reduce fitness load (keep them similar), or (2) breed a separate population to reduce captive-wild interactions as much as possible (make them different). We quantitatively evaluate these 2 strategies with a coupled demographic-genetic model based on Pacific salmon hatcheries that incorporates a variety of relevant processes and dynamics: selection in the hatchery relative to the wild, assortative mating based on the trait under selection, and different life cycle arrangements in terms of hatchery release, density dependence, natural selection, and reproduction. Model results indicate that, if natural selection only occurs between reproduction and captive release, the similar strategy performs better. However, if natural selection occurs between captive release and reproduction, the different and similar strategies present viable alternatives to reducing unintended fitness consequences because of the greater opportunity to purge maladaptive individuals. In this case, the appropriate approach depends on the feasibility of each strategy and the demographic goal (e.g., increasing natural abundance, or ensuring that a high proportion of natural spawners are naturally produced). In addition, the fitness effects of hatchery release are much greater if hatchery release occurs before (vs. after) density-dependent interactions. Given the logistical challenges to achieving both the similar and different strategies, eval

Artificial propagation strategies often incur selection in captivity that leads to traits that are maladaptive in the wild. For propagation programs focused on production rather than demographic contribution to wild populations, effects on wild populations can occur through unintentional escapement or the need to release individuals into natural environments for part of their life cycle. In this case, 2 alternative management strategies might reduce unintended fitness consequences on natural populations: (1) reduce selection in captivity as much as possible to reduce fitness load (keep them similar), or (2) breed a separate population to reduce captive-wild interactions as much as possible (make them different). We quantitatively evaluate these 2 strategies with a coupled demographic-genetic model based on Pacific salmon hatcheries that incorporates a variety of relevant processes and dynamics: selection in the hatchery relative to the wild, assortative mating based on the trait under selection, and different life cycle arrangements in terms of hatchery release, density dependence, natural selection, and reproduction. Model results indicate that, if natural selection only occurs between reproduction and captive release, the similar strategy performs better. However, if natural selection occurs between captive release and reproduction, the different and similar strategies present viable alternatives to reducing unintended fitness consequences because of the greater opportunity to purge maladaptive individuals. In this case, the appropriate approach depends on the feasibility of each strategy and the demographic goal (e.g., increasing natural abundance, or ensuring that a high proportion of natural spawners are naturally produced). In addition, the fitness effects of hatchery release are much greater if hatchery release occurs before (vs. after) density-dependent interactions. Given the logistical challenges to achieving both the similar and different strategies, eval

Colony size, nesting ecology and diet of Caspian Terns (Hydroprogne caspia) were investigated in the San Francisco Bay area (SFBA) during 2003-2009 to assess the potential for conservation of the tern breeding population and possible negative effects of predation on survival of juvenile salmonids (Oncorhyn-chusspp.). Numbers of breeding Caspian Terns declined 36% from 2003 to 2009, mostly due to abandonment of the Knight Island colony and decline of the Brooks Island colony, the two largest colonies in the SFBA. Concurrently, nesting success declined 69% associated with colony site characteristics such as (a) quality and quantity of nesting substrate, (b) vulnerability to nest predators, (c) displacement by other colonial waterbirds and (d) human disturbance. Marine fishes were the predominant prey in tern diets from the SFBA; however, diet composition varied among colonies. Juvenile salmonids comprised 22.9% of the diet of terns nesting in the North Bay, 5.3% of diet of terns nesting in the Central Bay, and 0.1% in the South Bay. Construction or restoration of nesting islands in the South Bay may help maintain and restore breeding Caspian Terns without enhancing mortality of salmonid stocks of conservation concern.

A l'heure actuelle, l'usage des nanoparticules est de plus en plus médiatisé. Elles sont maintenant utilisées à grande échelle et sont présentes dans tous les domaines : biologie, médecine, ingénierie, optique, électronique, mécanique, chimie, pharmacologie, cosmétique. Les nanoparticules sont utilisées en raison de leurs propriétés spécifiques. Dans le domaine médical, par exemple, les nanoparticules de Cd/S Cd/Te aussi nommées quantum dots (QDs) sont utilisées comme sondes fluorescentes. Quant aux nanoparticules d'argent (AgNPs), elles sont principalement employées pour leurs propriétés antimicrobiennes. Cependant, de récentes études ont démontrés que ces nanoparticules induisent une certaine toxicité. Malheureusement, peu de recherches ont été réalisées sur les nanoparticules et le système immunitaire. L'objectif principal de cette thèse était donc d'évaluer l'immunotoxicité des nanoparticules de Cd/S, Cd/Te et d'Ag sur des espèces modèles. Dans le cadre de ces travaux, nous avons défini quatre sous-objectifs: 1) déterminer l'impact des nanoparticules sur différentes cellules et systèmes immunitaires; 2) évaluer les facteurs influençant la toxicité des nanoparticules; 3) identifier les atteintes mécanistiques de la réponse immunitaire 4) établir la toxicité des nanoparticules en fonction des stress environnementaux. Afin d'évaluer la toxicité des ces matériaux émergents nous avons choisi d'étudier in vitro les performances du système immunitaire de quatre modèles d'animaux: l'humain, la souris (Mus musculus), la truite arc en ciel (Oncorhynchus mykiss) et la moule (Mytilus edulis). Ces espèces ont été définies car elles représentent des espèces sentinelles de leur milieu de vie. Ainsi, ces espèces sont souvent utilisées dans des études écotoxicologiques ou dans les études de risques. Dans un premier temps, nous devions déterminer l'impact de ces contaminants émergents sur les performances du système immunitaire. Les résultats des différents paramètres immunitaire

Recreational angling opportunities in lakes are distributed across landscapes and attract anglers based on the combination of angling quality, travel distance, and availability of facilities. The relationship between angler density and fishing quality, as measured by catch rate, represents a numerical response that is analogous to a predator numerical response to variability in prey abundance. We quantified this numerical response of anglers to rainbow trout, Oncorhynchus mykiss, populations distributed over a large lake district in south-central British Columbia, Canada. We developed a harvest dynamics model by linking this empirical description of the spatial numerical response of anglers to a logistic population growth rate model. The model was parameterized for rainbow trout and simulated spatial patterns of angler density and catch rates over a landscape. At locations distant from urban centers, angler density is low and catch rate high, suggesting near pristine conditions; at intermediate distances angler density is higher while catch rates are lower and approximate maximum sustainable levels; and at short distances angler density is sufficiently high to harvest to local extirpation. We extrapolated the model to other lake districts varying in human population size using an empirically derived angling participation rate relationship. Extrapolation to lake districts with one-tenth the human population maintained viable fisheries close to the urban area, and districts with 10 times the human populations could not maintain viable fisheries across much of their lake district. Landscape-scale spatial patterns differed quantitatively for species varying in rates of intrinsic population growth and carrying capacity, but the qualitative spatial patterns were consistent among species, demonstrating the pervasive impacts of the angler numerical response. To achieve a management goal of sustaining fisheries across landscapes, a change in management perspective is necessa

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecology 87 (2006): 1256–1266, doi:10.1890/0012-9658(2006)87[1256:FONIRF]2.0.CO;2., We introduced a 15N-NH4+ tracer to the riparian forest of a salmon-bearing stream (Kennedy Creek, Washington, USA) to quantify the cycling and fate of a late-season pulse of salmon-N, and, ultimately, mechanisms regulating potential links between salmon abundance and tree growth. The 15N tracer simulated deposition of 7.25 kg of salmon (fresh) to 4, 50-m2 plots. We added NH4+ (the initial product of salmon carcass decay) and other important nutrients provided by carcasses (P, S, K, Mg, Ca) to soils in late October 2003, coincident with local salmon spawning. We followed the 15N tracer through soil and tree pools for one year. Biological uptake of the 15N tracer occurred quickly; 64% of the 15N tracer was bound in soil microbiota within 14 days, and roots of the dominant riparian tree, western redcedar (Thuja plicata), began to take up 15N tracer within 7 days. Root uptake continued through the winter. The 15N tracer content of soil organic matter reached a maximum of ~52%, 5 weeks after the application, and a relative equilibrium of ~40% within 5 months. Six months after the addition, in spring 2004, at least 37% of the 15N tracer was found in tree tissues: ~23% in foliage, ~11% in roots and ~3% in stems. Within the stems, xylem and phloem sap contained ~96% of the tracer N, and ~4% was in structural xylem N. After one year, at least 28% of the 15N tracer was still found in trees, and loss from the plots was only ~20%. The large portion of tracer N taken up in the fall and reallocated to leaves and stems the following spring provides mechanistic evidence for a 1-year lagged tree-growth response to salmon nutrients. Salmon nutrients have been deposited in the Kennedy Creek system each fall for centuries, but the system shows no evidence of nutrient saturation. Rates of N uptake and retention are a function of site history, disturbance, and may also be the result of a legacy effect, in which annual salmon nutrient addition may lead to increased efficiency of nutrient, Funding was provided by the Hall-Ammerer Foundation, the Pacific Northwest Research Station of the US Forest Service, the University of Washington Sea Grant Program, and the National Science Foundation (DEB 98-06575).

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecology 87 (2006): 1256–1266, doi:10.1890/0012-9658(2006)87[1256:FONIRF]2.0.CO;2., We introduced a 15N-NH4+ tracer to the riparian forest of a salmon-bearing stream (Kennedy Creek, Washington, USA) to quantify the cycling and fate of a late-season pulse of salmon-N, and, ultimately, mechanisms regulating potential links between salmon abundance and tree growth. The 15N tracer simulated deposition of 7.25 kg of salmon (fresh) to 4, 50-m2 plots. We added NH4+ (the initial product of salmon carcass decay) and other important nutrients provided by carcasses (P, S, K, Mg, Ca) to soils in late October 2003, coincident with local salmon spawning. We followed the 15N tracer through soil and tree pools for one year. Biological uptake of the 15N tracer occurred quickly; 64% of the 15N tracer was bound in soil microbiota within 14 days, and roots of the dominant riparian tree, western redcedar (Thuja plicata), began to take up 15N tracer within 7 days. Root uptake continued through the winter. The 15N tracer content of soil organic matter reached a maximum of ~52%, 5 weeks after the application, and a relative equilibrium of ~40% within 5 months. Six months after the addition, in spring 2004, at least 37% of the 15N tracer was found in tree tissues: ~23% in foliage, ~11% in roots and ~3% in stems. Within the stems, xylem and phloem sap contained ~96% of the tracer N, and ~4% was in structural xylem N. After one year, at least 28% of the 15N tracer was still found in trees, and loss from the plots was only ~20%. The large portion of tracer N taken up in the fall and reallocated to leaves and stems the following spring provides mechanistic evidence for a 1-year lagged tree-growth response to salmon nutrients. Salmon nutrients have been deposited in the Kennedy Creek system each fall for centuries, but the system shows no evidence of nutrient saturation. Rates of N uptake and retention are a function of site history, disturbance, and may also be the result of a legacy effect, in which annual salmon nutrient addition may lead to increased efficiency of nutrient, Funding was provided by the Hall-Ammerer Foundation, the Pacific Northwest Research Station of the US Forest Service, the University of Washington Sea Grant Program, and the National Science Foundation (DEB 98-06575).

Uit onderzoek naar het gedrag van melkzuur in het vissenlichaam na uitputtende zwemarbeid in een zwemtunnel blijkt dat vissen een spiercompartiment bezitten met aanleg tot de productie van veel melkzuur. Dit melkzuur wordt nauwelijks vanuit het spiercompartiment afgegeven naar het bloed- of levercompartiment. Beperkte hoeveelheden melkzuur uit het bloedplasma zullen als brandstof dienen voor oxidatieve weefsels als rode spier en hart; de grootste hoeveelheid van het melkzuur zal uiteindelijk in de spier zelf afgebroken worden. In figuren de melkzuurconcentraties en de recycling van melkzuur in witte en rode spier, leverweefsel en bloedplasma, en in een tabel de metingen van een aantal bloedparameters. Het onderzoek werd gedaan met de gewone karper (Cyprinus carpio) en regenboogforel (Oncorhynchus mykiss)

Verslag van een onderzoek naar de herstelmechanismen in de spieren van forel en karper, na uitputting in een zwemtunnel, en uitleg over de daarbij gebruikte kernspinresonantie-techniek (NMR: Nuclear Magnetic Resonance). Met deze techniek werd informatie verkregen over het verloop van de herstelprocessen in de witte spier van energierijke verbindingen en afbraakproducten (suikerfosfaten; phosphocreatine; adenosine-trifosfaat; anorganisch fosfaat) en van de intracellulaire pH (een maat voor de verzuring van het spierweefsel). Uit het onderzoek bleek dat bij de uitgeputte dieren een mortaliteit optrad van circa 50 procent, en dat een tekort aan energie en niet verzuring de oorzaak is voor deze sterfte. De vraag blijft open wat primair de doodsoorzaak is, het eigenlijke energietekort of het hierdoor verminderd in staat zijn om afvalstoffen te verwijderen

Utah Conservation Data Center Species fact sheet and distribution map on the Bonneville cutthroat trout, Oncorhynchus clarkii utah.

Utah Conservation Data Center Species fact sheet and distribution map on the Lahontan cutthroat trout, Oncorhynchus clarkii henshawi.

Utah Conservation Data Center Species fact sheet and distribution map on the golden trout, Oncorhynchus aguabonita.

Utah Conservation Data Center Species fact sheet and distribution map on the Lahontan cutthroat trout, Oncorhynchus clarkii henshawi.

Utah Conservation Data Center Species fact sheet and distribution map on the golden trout, Oncorhynchus aguabonita.

Utah Conservation Data Center Species fact sheet and distribution map on the Bonneville cutthroat trout, Oncorhynchus clarkii utah.

The current status of techniques and developments relating to the long-term identification of salmonid fish is reviewed and described. The literature that may relate to future techniques is discussed. Techniques include coded wire tags, passive integrated responders, branding, tetracycline, fluorescent pigments, dyes and microtaggants, meristics and morphometrics, electrophoresis and serological techniques, genetic tagging, and parasites.