Two ecologically important lamprey species found in the endorheic Goose Lake Basin face conservation threats; however, relatively little is known about their habitat needs or spatial distribution. Lamprey and their habitat are often found to be patchy; to evaluate these relationships for the lamprey in this basin, I utilized a...
The Goose Lake Basin, situated on the border of Oregon and California, USA, faces significant challenges from drought, wildfire, and other environmental stressors. This region hosts numerous endemic fish species such as the Goose Lake redband trout (Oncorhynchus mykiss newberri), Goose Lake lamprey (Entosphenus sp.), Goose Lake tui chub (Siphateles...
The California Current Large Marine Ecosystem (CCLME), located on the eastern boundary of the North Pacific Ocean, is highly dynamic, with variable conditions driven by seasonal upwelling, regional oceanography, and broad scale climate patterns. In the last decade, the northeast Pacific Ocean has experienced several marine heatwaves (MHWs), prolonged periods...
Devaleraea mollis (Pacific Dulse) is becoming a popular food for human consumption. Previously, Pacific Dulse has been used as a nutrient source for cultured abalone species, with some historical food use by indigenous peoples, while the closely related Atlantic dulse (Palmaria palmata) has a long-documented history of use in cuisine...
Standard larval Pacific oyster (Crassostrea gigas) rearing systems can be described as either static or continuous flow. While rearing oyster larvae in static cultures can be a low-cost and simple method, static systems require significant husbandry effort, floorspace and can produce highly variable results due to environmental variance among cultures....
It is well documented that microplastics and semi-synthetic particles (<5 mm) pervade the marine environment, with their ingestion by marine fauna eliciting global concern. While fishes exposed to microparticles in a laboratory setting have exhibited both sub-lethal and lethal effects, the diversity in material, morphology, and size of these contaminants...
Streams across the western United States are impaired from human alterations that have reduced freshwater habitat by simplifying channel complexity and disconnecting floodplains (Knox et al., 2022; Waples et al., 2008; Wohl, 2014). Climate change is likely to continue exacerbating these risks by warming summer surface stream temperatures (Crozier et...
Our understanding of seasonally disconnected floodplains and how they function to support rearing salmonids in the Pacific Northwest is limited. Past studies have found that these dynamic habitats may provide high-risk, high-reward trade-offs for rearing fish. High prey densities and optimal temperatures allow for accelerated growth, but low water levels...
Juvenile Chinook Salmon (Oncorhynchus tshawytscha) leave the natal reach at different times and move downstream at different rates which can increase their productivity by allowing them to utilize habitats on different temporal scales and spreading risk of localized stochastic events. This life history diversity can also allow fish to adapt...
The freshwater copepod Salmincola californiensis is an ectoparasite of Pacific salmonids (Oncorhynchus spp.) Threatened and endangered salmonids that rear in the reservoirs have been reported to experience higher rates of infection by S. californiensis than would be experienced by their stream-reared counterparts. These high levels of infection can lead to...
Connectivity of fish populations is a crucial question for fisheries conservation and the development of spatial management plans. Both adult and larval movement define the extent and direction of ecological and evolutionary overlap between geographic regions and, therefore, how we define stocks for management purposes. Within that context, my work...
Annual rates of prespawn mortality (PSM) in adult Chinook salmon (Oncorhynchus tshawytscha) trapped and transported upstream of dams in the Willamette River basin are high (often >40%) and could limit the ability to restore natural populations of spring Chinook salmon if not reduced. Improvements at the U.S. Army Corps of...
Once abundant in their native range, Pacific salmon species (Oncorhynchus spp.) were widely distributed across the northern Pacific Rim from South Korea and Japan to the Sacramento River in California. Remaining populations are subject to population-level threats, including pathogens. The freshwater parasitic copepod Salmincola californiensis is associated with the reduced...
In recent years, there has been an increase in episodic coastal hypoxia along the mid to inner-shelf waters off the Oregon Coast. Wind-driven coastal upwelling events can exacerbate the magnitude of these hypoxic events, causing extremely hypoxic bottom water (<0.5ml l-1 dissolved oxygen) to move onshore towards the inner shelf....
Bioturbation caused by ghost shrimp, Neotrypaea californiensis, burrowing activity can negatively affect Pacific oyster, Crassostrea gigas, aquaculture through their burial and subsequent suffocation. The shellfish aquaculture industry used chemicals to control burrowing shrimp populations in Washington State estuaries for decades, but, due to public and governmental scrutiny, that practice has...
Food webs are fundamental in ecology, as they offer a way to better understand the interrelatedness, connectivity, and complexity within a given ecosystem. The use of network analysis to model food webs can provide insights about the importance of physical templates on the organization of biological systems in streams using...
Headwater streams in the Oregon Coastal Range are subject to drastic fluctuations in flow and temperature because of the changing seasonality of a Mediterranean climate. In response to these changes, stream fishes exhibit a variety of movement patterns. Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) have evolved an assortment of life...
Contemporary stream restoration efforts increasingly prioritize restoring natural stream processes to regain lost ecosystem functions. Stage 0 stream restoration resets disturbed, channelized streams to a theoretical pre-disturbance state (“stage zero”). It is assumed that this valley-scale restoration/disturbance will restore natural abiotic and biotic processes, leading to greater primary and secondary...
Fisheries managers often use models of population density to evaluate the status of stream-living fishes, but many of these models have low predictive performance for abundance and density. These models could incorporate several factors that can limit population density, particularly the effect of body size, envisioned by the theory of...
The introduction of non-native species can negatively impact native species through reduced genetic fitness resulting from hybridization. The lack of spatiotemporal data of hybrids occurrences makes assessing hybridization risk difficult. Here, I developed a spatially-explicit GIS Hybridization Risk Model (HRM) between native ESA-listed Bull Trout and introduced Brook Trout by...
Decision-making is a highly complex process influenced by the values, attitudes, and cognitive biases of the decision-maker. The classical model of decision-making fails to fully incorporate how decisions are made in situations of uncertainty, where having complete knowledge of all possible outcomes and alternatives is not always possible. In highly...
Despite growing efforts to recruit individuals from diverse backgrounds, natural resources fields, including marine aquatic and fisheries science, do not reflect the diversity of the United States. This dissertation utilized three studies to explore underrepresentation in marine, aquatic, and fisheries sciences by examining career influences, experiences, and perspectives at different...
Microplastics are ubiquitous in our oceans, yet we are still clarifying what risks they pose to marine organisms, which can be challenging due to their trait diversity and spatial patchiness. Laboratory-based studies assessing risk demonstrate that many marine animals internalize microplastics, either actively through ingestion or passively via respiration. However,...
Population genetic techniques are now preeminent in differentiating wild populations. Natural resource managers rely on them in their efforts to restore viable populations of fish and wildlife. Overfishing adversely impacted Yelloweye Rockfish (Sebastes ruberrimus) on the U.S. West Coast in the late 20th century. Management actions included shutting down the...
The natural environment provides important services and benefits to peoples’ health and lives. Conversely, environmental disservices can have negative impacts on humans such as through pollution, chemical toxins, and climate change. The combination of environmental services and disservices encompass how human health and wellbeing, and the environment are connected. As...
Riparian forests provide a myriad of ecosystem functions for adjacent streams and rivers, and due to these linkages, changes in riparian forest conditions can have direct implications for stream ecosystems. Resource managers in the coast redwood forests (Sequoia sempervirens) of northern California (USA) are actively thinning second-growth stands to accelerate...
Climate change is a global phenomenon, but natural selection occurs within landscapes. A central tenet of landscape ecology is that mobile species depend on complementary habitats, which are insufficient in isolation, but combine to support animals through the full annual cycle. For coldwater fishes, it is widely assumed that maximum...
Aquatic and riparian systems in the western United States have been highly modified by anthropogenic impacts since Euro-American settlement. Ecological restoration is a practice that has been widely conducted around the world to mitigate the degradation of these systems. The majority of stream restoration efforts have focused on improving in-stream...
Microplastics (<5mm diameter) are present in a considerable number of marine and aquatic species. Understanding which species, the global spatial distribution, and what quantities of microplastics are present is extremely important for understanding the potential impacts they could have on recreationally important organisms and for the assessment of risk. We...
RNAseq data among copepods (Calanus pacificus) were sampled and analyzed in relation to oceanographic and climatic conditions to determine if new information derived from such an approach might assist applications that use copepods as ecosystem indicators to predict fishery yields. These samples were taken as part of long-term studies conducted...
The relationship between population characteristics and population productivity is fundamental to sustainable fisheries management, but predicting productivity remains a challenging task. Proposed mechanisms driving the variability in productivity at a given population size have included environmental and demographic factors related to the age structure of the population, but the broad-scale...
Many economically important Pacific salmon fisheries along the west coast of North America are mixed-stock, recreational systems, in which managers strive to account for interactions between fish, anglers, and management policy while balancing fishery access against conservation of vulnerable stocks. Specific challenges facing fisheries managers include limited control over angling...
An inextricable link exists between dams and human development in the Pacific Northwest, but they can fragment rivers and reduce genetic connectivity for freshwater and anadromous fishes. Since the early-twentieth century, a series of hydropower and irrigation dams on the mainstem Klamath River, California, has fragmented migratory corridors and eliminated...
The anadromous Pacific Lamprey (Entosphenus tridentatus) is a biologically and culturally important species native to the North Pacific Ocean and its adjacent freshwater tributaries. Pacific Lamprey have experienced declines in abundance and distribution throughout their native range, highlighting a need for further research on the species to better inform conservation...
Animal weapons are thought to have evolved to compete for reproductive opportunities within a species. Across the diverse weapon-bearing taxa, several evolutionary trends have emerged: (1) increasing complexity and relative size across ontogeny, (2) sexual dimorphism, and (3) higher levels of random deviations from symmetry (i.e., fluctuating asymmetry) than non-weaponized...
Freshwater rearing is a critical period in the life cycle of anadromous salmonids, known to produce carry-over effects mediating long-term growth and survival. Freshwater growth is primarily determined by food availability and temperature. While many species of salmon rear in freshwater for a full year or longer, most trophic ecology...
Pacific salmon (Oncorhynchus spp.) rearing in lakes and reservoirs have been known to become heavily infected with an ectoparasitic copepod (Salmincola californiensis). Little is known about the factors that affect the parasite infection prevalence and intensity. However, previous research suggests that the parasite may negatively affect the fitness and survival...
Fisheries management that is based on quantitative assessment has commonly relied on estimating the unfished biomass of a fished stock to compare current and historical population size. Developing predictive models for this requires many years of catch and abundance data. Smaller, new, or mainly recreational fisheries may not have the...
Shallow lakes exist in either a clear or turbid state, with the clear state characterized by an abundance of aquatic macrophytes, diverse aquatic biota, low water column nutrients and phytoplankton biomass, whereas the turbid state is characterized by the opposite. These two distinct states are maintained by reinforcing (positive) feedback...
The role that anthropogenic and natural habitats in estuaries play in long-term population trends for Oregon’s nearshore marine fishes is poorly understood, in part due to limited temporal sampling. One important nearshore marine group is northeastern Pacific rockfishes (Sebastes spp.), which are highly diverse, with around 96 documented species, and...
As regional climates warm in the Pacific Northwest, USA, flow minima and temperature maxima may become more synchronous in headwater streams over time. The dual stresses from lower flows and warmer temperatures will be energetically costly for cold-water species such as Coastal Cutthroat Trout and Coastal Giant Salamander. Individual fates...
Somatic growth variation manifests from the cumulative effects of a suite of biological, ecological, and environmental processes and can have profound effects on individual fitness and species population dynamics. As ectotherms whose growth dynamics are greatly influenced by environmental factors, sea turtles display considerable variation in somatic growth within and...
Projected intensification of drought as a result of climate change may reduce the capacity of streams to rear fish, exacerbating the challenge of recovering ESA-listed salmon populations. Without management intervention, some stocks will likely go extinct as stream drying and fragmentation reduce juvenile survival to unsustainable levels. To offset drought-related...
The Columbia River Basin historically supported abundant populations of Pacific salmon (Oncorhynchus spp.) but, largely due to anthropogenic influence, many populations are now listed as threatened or endangered under the U.S. Endangered Species Act. Habitat restoration efforts have been a critical component of salmon recovery plans. However, although the importance...
The California Current Ecosystem (CCE) is a dynamic marine ecosystem from which many socioeconomically important fisheries species are harvested. In this thesis, a genotyping-by-sequencing (GBS) approach was used to examine genomic variation in an early life stage of the Dungeness crab (Cancer magister), which constitutes the most valuable single-species commercial...
Anadromous salmonid populations in the Pacific Northwest have declined over the past 150 years. In 1999, wild spring Chinook salmon (Oncorhynchus tshawytscha) were federally listed as threatened within the Willamette Basin, OR. Currently, practices to restore wild populations in the upper Willamette Basin involve trapping wild adults at the base...
Chinook salmon are widely distributed across the globe with native stocks in the North Pacific Ocean and self-sustained populations introduced to regions in the Northern and Southern Hemispheres. Pacific salmon are economically and ecologically important to the Pacific Northwest, USA, yet several wild populations are federally listed as endangered or...
The goal of my dissertation was to explore how scale influences stream restoration prioritization strategies for an anadromous species and identify influential uncertainties that exist at different scales. My objectives were to (1) produce a comprehensive review of the Chinook salmon management challenges in California’s Central Valley and identify the...
The Pacific Oyster (Crassostrea gigas) is one of the most economically and ecologically significant shellfish species worldwide. In the Pacific Northwest United States (PNW), the sustainability oyster stocks is increasingly threatened by ocean acidification (OA), which has had significant negative effects on the aquaculture industry in this region over the...
Humans have drastically altered the physical habitat and food web structure of stream ecosystems. Two major impacts humans have had on Pacific Northwest streams are modification of streamside forests (as a result of agriculture, land development, and timber harvest), and declines in the return of wild anadromous salmon to headwater...
Large dams and their respective reservoirs can provide renewable energy and water security, but also profoundly alter riverine ecosystems. In the Pacific Northwest, dams and reservoirs cause discontinuities in river networks that have been particularly problematic for anadromous fishes. As barriers to the upstream and downstream migration of anadromous fishes,...
In Southeast Alaska, Eulachon (Thaleichthys pacificus) are a culturally and biologically important anadromous fish. Eulachon populations have significantly declined in the southern part of their range, and in 2010 eulachon in northern California, Oregon, and Washington were listed as a threatened species under the Endangered Species Act. In the same...
Globally, the number of threatened species is increasing and conserving them is a high priority to the scientific community. Assessing the status of these protected species is challenging due to missing, contested, and or contradictory data streams. Integrated models (IMs) provide a statistical framework for combining disparate data sources to...
The structure of food webs and how they relate to community stability has been an important debate in ecology. Specifically, predictability of web shape and how it influenced by surrounding landscapes is one of the main goals of such discussions. Headwater streams provide a study template that is of interest...
The National Park Service has a dual mission of providing public access to exceptional natural resources, but in a manner such that these resources are left “unimpaired for the enjoyment of future generations.” Human activities in parks undoubtedly affect wildlife, but the degree to which such activities cause impairment is...
Vibrio coralliilyticus (Vcor) is a bacterial pathogen that is well adapted to shellfish hatcheries and is very pathogenic to the larvae of the Pacific oyster Crassostrea gigas. Vcor has been associated with several large scale larval mortality events in the Pacific Northwest that interrupt the supply of seed oysters available...
The social sciences have the capacity to contribute to natural resource management through investigations of human dynamics associated with the environment. Sense of place (SOP), the formed relationships between an individual and the environment, has been considered a fundamental aspect of human well-being and can contribute to more holistic understanding...
Small-scale fisheries (SSF) around the world face many challenges. They are a highly dynamic, important sector for coastal communities in developing nations, playing a critical role in poverty alleviation and food security. SSFs generally have few resources to ensure their long-term sustainability. They are often fished and managed locally and...
Migration and spawning phenology of Pacific Salmon is linked to the hydroregime, and thought to be triggered by increases in river discharge and decreases in water temperature. However, little data exists that describes direct fine-scale linkages between the hydroregime and spawning in Coho Salmon. This study evaluated the spatial and...
The management of small-scale fisheries (SSF) around the world is facing increasing demands for reformation given ecological, social, and economic vulnerabilities. The governance of SSF is particularly important to foster the sustainability of these systems given that it combines regulatory instruments, interactive participation of diverse stakeholders, and the guiding values...
Biodiversity loss in highly diverse systems such as coral reefs has been linked to significant declines in the ecosystem functions and services provided by marine species. Ecological functioning of coral reefs and the resistance of coral reef fish communities to disturbance depend on the functional traits of species that promotes...
Characiform fishes form one of the most diverse freshwater fish clades in the world. Comprising more than 2000 species and distributed primarily in South America and Africa, characiforms vary dramatically in their ecomorphology. However, the evolutionary processes responsible for the immense ecomorphological diversity remains unknown. Recently, a study postulated that...
In this study, we used a combination of conventional statistical analyses and mechanistic bioenergetics models to understand the potential effects of environmental variability on growth of stream-living fishes in four headwater streams subject to upstream forest harvest. We focused on two common fish consumers in headwater streams in the Pacific...
Traditional analysis in population genetics evaluates differences among groups of individuals and, in some cases, considers the effects of distance or potential barriers to gene flow. However, many forces may shape genetic variation of organisms in riverine systems. Similarly complex research linking habitat heterogeneity and configuration to genetic structure has...
Tropical peatlands play an important role in global climate system by storing an immense of carbon that had been accumulated over thousands of years. Peatlands provide another important ecosystem service by regulating the hydrology. It is believed that peatlands act like a giant sponge by absorbing substantial amounts of water...
Ecological resources available to freshwater fish shift spatially, temporally and across life stages. To better understand how spatial-temporal availability of resources influence fish, I examined the phenologies of hatching and emergence of Coho Salmon (Oncorhynchus kisutch) in streams with contrasting and strongly defined seasonal thermal variability. The study streams included...
Listed as endangered in 1988, the Lost River sucker (Deltistes luxatus) and Shortnose sucker (Chasmistes brevirostris) were once abundant and widely distributed in the Klamath Basin in Southern Oregon and Northern California. Populations of both species have been declining since the late 1960’s. Factors thought responsible for declines include naturally...
The direct and indirect effects of ocean acidification (OA) are a growing concern, particularly in areas already experiencing elevated levels of oceanic CO₂. Studies with marine fishes suggest that elevated CO₂ levels may affect behavior by interfering with an important brain neurotransmitter. Studies examining the effects of OA fish behavior...
The early marine phase following freshwater emigration has been identified as a critical period in salmonid (Oncorhynchus spp.) life history, characterized by high but variable mortality. Consistent with the “growth-mortality” and “bigger-is-better” hypotheses, at least some of the mortality during the critical period appears to be size-dependent – with smaller...
The effects of Marine protected areas (MPAs) on adult fish populations depend on the degree of protection provided, which is partly a function of MPA size and the spatial extent of fish movements. The Redfish Rocks Marine Reserve (RRMR) and MPA, located on the south coast of Oregon near Port...
Understanding connectivity among exploited populations is critical to their sustainable management and long-term viability. In the marine environment, estimates of connectivity often rely on the use of genetic markers, as dispersal primarily occurs during a planktonic larval phase which is difficult to track using direct methods. In this thesis, we...
Juvenile Chinook Salmon (Oncorhynchus tshawytscha) have a finite amount of energy that they can use to move from their riverine habitat to their oceanic habitat. Fish in the Willamette River Basin are prevented from moving to the ocean easily by dams which create reservoirs, where they reside for up to...
Accumulating human impacts on freshwater ecosystems have created a biodiversity crisis for freshwater fishes while conservation efficacy remains hampered by the Linnaean shortfall, the ignorance of many species that have yet to be discovered and described. The past discovery of most freshwater fish species was simply a matter of collecting...
Thiamine (vitamin B₁) is required by all living organisms for carbohydrate metabolism and synthesis of amino acids. Thiamine deficiency is responsible for several related classes of early life stage mortality disorders in salmonines, including Thiamine Deficiency Complex (TDC) in the Laurentian Great Lakes, Cayuga Syndrome in the Finger Lakes, and...
More than 1500 species of plants and animals in the United States are listed as threatened or endangered under the Endangered Species Act (ESA). The U.S. Departments of Interior and Commerce are required, under Section 4(f)(1) of the ESA, to develop recovery plans for ESA-listed species under the respective agency...
Two indigenous species of burrowing shrimp inhabit and often dominate the intertidal zone of estuaries along the US West Coast, the ghost shrimp, Neotrypaea californiensis, and the blue mud shrimp, Upogebia pugettensis. Both species are considered ecosystem engineers and play a role in maintaining estuarine health and ecosystem function. They...
Rivers impacted by human activities often have multiple stressors present. The effects of multiple stressors on biological communities can often be difficult to predict, due to the potential for complex interactions between stressors and communities. This thesis explores the impacts of two stressors often associated with agricultural land use, increased...
Estuaries, which provide viable habitat for a plethora of fish and invertebrate species, are being increasingly impacted by anthropogenic and natural forces. Estuaries are important nursery habitat for young-of-the-year (YOY) Pacific rockfish (Sebastes spp.). Yaquina Bay, a marine-dominated estuary on the central Oregon Coast, served as a study site for...
Green sea turtles, Chelonia mydas, have endangered and threatened populations globally, but several populations show signs of population recovery. In Hawaii, nesting female green turtles have increased 5.7% year⁻¹ since 1973, but wide fluctuations in census counts of nesting females make recovery diagnosis difficult. For effective management planning, it is...
Rapid adaptation and evolution based on standing genetic variation and novel mutations is likely to be one of the primary ways that species survive the widespread anthropogenic environmental changes expected of the next century. Three-spined stickleback (Gasterosteus aculeatus) are known to be capable of extremely quick, dramatic adaptation in response...
All animals that interact with fishing gear are not necessarily captured, and all animals that are captured are not necessarily retained. Fishing practices and gear configuration, management regulations, and markets dictate which animals ultimately are retained or discarded. The impact of a fishery and the efficacy of management regulations can...
This dissertation addresses gaps of knowledge associated with how ecosystem carbon stocks and greenhouse gas emissions are affected by land use land cover change in tropical peatlands. This was the first study that paired peat swamp forests with oil palm plantations and analyzed site scale variation on greenhouse gas emissions....
Reintroduction programs are used to re-establish species back into their historical habitat. Most reintroduction programs have failed and few papers have evaluated factors that may be important to Pacific salmon. The 158 meter tall Cougar Dam has blocked Chinook salmon (Oncorhynchus tshawytscha) from accessing 40 kilometers of historical spawning and...
Loss of lowland estuarine and freshwater off-channel habitats along the Pacific Northwest coast has contributed to the decline of salmonid populations. These habitats serve as nursery grounds for juvenile salmonids providing them with food, winter shelter, and a transition zone between freshwater and saltwater. Lowland areas have undergone anthropogenic alterations...
Marine bivalves are globally recognized as ecologically and commercially valuable species and, for over a century, researchers have been studying their feeding, digestion and other related physiological processes. These studies have shown that marine bivalves have complex feeding and particle processing behaviors to maximize growth in dynamic environmental conditions. Additionally,...
Neotropical characiform fishes form one of the most diverse freshwater ichthyofauna in the world. Knowledge of evolutionary processes that generated and maintain the immense characiform lineage and morphological diversity is still poorly understood. When did characiform lineages diversify? How have major geological and environmental changes affected diversification? Why are some...
Marine systems undergo changes in community composition over time as a result of a variety of environmental and anthropogenic factors. Understanding these community changes and the factors that drive them is critical for ecosystem management of marine resources. The Gulf of Alaska (GOA) is a large marine ecosystem that includes...
In the wild, marine fish larvae feed on copepods and other planktonic organisms.
Copepods are often considered the "gold standard" for meeting the nutritional needs of cultured marine fish larvae; however, in captivity, marine fish larvae are generally fed cultured live prey, i.e. rotifers (Brachionus plicatilis) and/or Artemia sp., until...
Salmon hatcheries have been utilized throughout the Pacific Northwest for many decades to mitigate losses, supplement natural spawning populations, and to provide tribal, sport and commercial fishing opportunities. Currently, there is substantial debate on their efficacy and the potential threats hatchery-reared salmonids pose to natural populations. These concerns have lead...
Numerous populations of salmon and trout undergo extensive migrations, migrating from freshwater to the sea and throughout ocean basins. Years later they return to their natal streams with remarkable accuracy and precision. The outward migration is accomplished without the benefit of following experienced migrants or prior individual experience. Evidence suggests...
Streams across the world are highly fragmented due to the presence of in-stream barriers (e.g., dams and stream-road crossings), many of which restrict or block fish passage. Retrofitting or replacing these structures is a high priority for restoring habitat connectivity for native fishes and other aquatic organisms in the Pacific...
Stock assessments use statistical models and empirical data to re-create the population dynamics of a stock in order to provide estimates of biomass and fishing mortality rates to inform fisheries management. Fish stocks are not uniformly distributed across spatial regions, but stock assessments typically ignore stock spatial structure, for the...
Understanding the effects of climate variability on growth dynamics and timing of early life history events in marine fishes can provide insights into survival, recruitment and productivity. Field collections (2005, 2007, 2009-2011) were combined with otolith microstructural analysis to examine interannual variation in larval and juvenile growth rates, size at...
Mercury (Hg) contamination is a global conservation threat to freshwater ecosystems, detected in even the protected lakes of Olympic National Park (Washington, USA). Although considered some of the most remote and pristine US ecosystems, these lakes are currently subject to multiple environmental stressors, including climate change and fish introductions; adding...
Pacific lamprey Entosphenus tridentatus is a valuable icon and traditional food source for Indigenous people of western North America. Native Americans have utilized traditional ecological knowledge (TEK) since time immemorial to guide their ways of life, transmitting cultural values and natural history to further generational knowledge. Pacific lamprey are in...
Juvenile Chinook salmon (Oncorhynchus tshawytscha) exhibit an array of life history tactics in Oregon's Willamette River Basin, yet we do not know to what extent it is driven by phenotypic plasticity or whether it is predetermined and how conditions in the early rearing environment may affect phenotype expression. We have...
Ontogenetic niche theory predicts that as organisms grow they make size-specific changes in habitat use and diet to optimize growth and survival. A variety of factors contribute to growth and survival in different habitats, ultimately leading to variation in life history that can affect population dynamics. An understanding of the...
In this study, I examine the influence of habitat gradients created by the 1980 eruption of Mount St. Helens, Washington USA on a recently established Rainbow Trout (Oncorhynchus mykiss) population in the Spirit Lake basin. My goal was to evaluate the responses of fish in seven streams across a volcanic...
Large wood has been utilized in many restoration projects to improve in-stream habitat in the Pacific Northwest for salmon. However, the benefits of this practice remain the subject of ongoing debate and evaluation of these projects has scarcely been done for non-salmonid species such as lamprey. In this study we...
Substantial scientific investment has been directed towards understanding factors that influence distribution patterns and animals' remarkable ability for precise orientation and navigation, yet fundamental gaps in our knowledge remain. In my dissertation, I applied emerging genetic technologies to conduct a top-down and bottom-up investigation of animal movement and cue perception....