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...
Most marine fishes experience high rates of mortality during their early life history stages with far reaching consequences for adult population dynamics. Within a few weeks of hatching, relatively small changes in larval growth and mortality rates can lead to orders of magnitude variability in year-class strength. Growth and survival...
Anthropogenic carbon dioxide emissions are causing ocean acidification (OA) and ocean warming, which have negative effects on the larvae of many marine invertebrates. Oregon pink shrimp (Pandalus jordani) currently encounter upwelling events that can result in pH values as low as 7.6, and, more recently, marine heat waves that raise...
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...
The aim of this dissertation is to construct a virtual element method (VEM) for models in magneto-hydrodynamics (MHD), an area that studies the behavior and properties of electrically conducting fluids such as a plasma. MHD models are a coupling of the Maxwell’s equations for electromagnetics and models for fluid flow....
Environmental injustices, defined as inequitable access to fair, safe, and healthy environmental outcomes, are often rooted in issues of land management, policy decision making, and sovereignty. This results from a series of processes, including loss of land ownership, exclusionary and discriminatory zoning, and structural barriers to participation. Black, Indigenous, Communities...
Dynamic seascapes, which are classified using a combination of remotely sensed data and model output, represent a potential tool for dynamic ecosystem-based management in marine systems. This work explores the utility of seascape classification in the context of marine resource management by examining two case studies: one involving biological relationships...
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...
Anomaly detection aims at detecting the points that appear different than the majority of the data, such that they are suspected to be generated from a different distribution. Anomaly detectors have been applied in many different fields, such as detecting fraudulent behaviors in bank transaction, finding broken sensors in a...
Survival of marine fishes during their early life history stage is tightly related to prey availability and predation pressure. Yet, our understanding of how individual larvae to entire assemblages are constrained by these factors is limited. We integrated biological sampling of larval fishes with fine-scale in situ imaging to relate...
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...
Anatomically correct biota phantom creation has suffered from three primary weaknesses: the models take considerable time to make, are limited in detail by voxel size, and are created and simulated using proprietary software. Presented are trial runs of a new biota creation pipeline, FSOPhantom, that addresses these issues by creating...
Euphausiids are recognized as essential components of marine food webs throughout the world’s oceans due to their role as prey for many species including whales, seabirds, and commercial fishes. The Kitimat Fjord System is an important fisheries area and is the only fjord habitat on the British Columbia coast that...
In Oregon, commercial fishing is estimated to contribute $544 million in income and 10,000 jobs per year to coastal communities. However not all fisheries are reaching their allocated quotas for catch. In 2017, 187.6 million pounds of non-whiting groundfish trawl quota worth $67 million was not attained, nearly three times...
Ian Angell, in the New Barbarian Manifesto, said “A ‘brave new world’ is being forced upon unsuspecting societies by advances in information technology.” It would seem then, that technological advances happen automatically and have a life of their own. There is a logic to technological advancements that is outside human...
Biological invasions and climate change represent two preeminent threats to ecological communities and biodiversity, altering the distribution and abundance of species, disrupting existing species interactions and forming unprecedented ones, and creating novel ecological communities. Many of the most successful invasive species are also ecosystem engineers, species that physically modify the...
Arctic cod (Boreogadus saida) is an ecologically significant species that plays a critical role channeling energy throughout the Arctic marine food web. Arctic cod is uniquely adapted to occupy ice edge habitats, however, a basic understanding of its larval physiology and habitat requirements is lacking due to widespread sea ice...
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...
The mouth of the Columbia River (MCR) is an intersection of more than a river and ocean, but also multiple economically valuable activities including dredging to maintain a deep draft shipping channel and an active Dungeness crab (Metacarcinus magister) fishery. More than three million cubic meters of sediment are annually...
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...
Understanding the factors that contribute to or limit reproductive success is a fundamental objective of the field of ecology, providing insight into the ways ecosystems function and facilitating better management of natural resources. Behaviors that benefit offspring often increase costs to parents, and thus parents must adjust their level of...
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...
The first objective of this study was to quantify the intensity of space use of 70 juvenile (12-26 months old) Steller sea lions (SSLs) from the western Distinct Population Segment (DPS) in the Kenai Fjord(KF)/Prince William Sound (PWS) region of Alaska as derived from externally attached ARGOS satellite transmitter tags....
Variable ocean conditions can greatly impact lower trophic level prey assemblages in marine ecosystems, with effects propagating up to higher trophic levels. Our goal was to better understand how varying ocean conditions influence diets and niche overlap among a suite of low- to mid trophic level predators. We studied the...
Understanding the movement behavior and foraging strategies of individuals across multiple spatial and temporal scales is essential not only for understanding the biological requirements of individuals but also for linking individual strategies to population level effects. Glacial fjords scattered throughout south-central and southeastern Alaska host some of the largest seasonal...
Effective and sustainable fisheries management not only depends on identifying and defining stocks (fundamental unit of management), but also on having knowledge of factors influencing the abundance, distribution and connectivity of stocks. Population structure of Pacific cod (Gadus macrocephalus) in the southeastern Bering Sea (EBS) remains unresolved although genetic data...
Juvenile walleye pollock (Theragra chalcogramma) are one of the primary prey items for bird and mammal predators in the Bering Sea and support a large commercial fishery. An understanding of the environmental factors that determine the horizontal and vertical distribution of juvenile pollock is needed to estimate the effects that...
Small pelagic fish represent a critical trophic link between plankton and large predators in marine upwelling ecosystems such as the California Current System. Populations of these fish are highly variable over time and are characterized by extreme fluctuations in abundance, which have significant ecosystem impacts. The causes driving
this instability...
Salmon survival and eventual recruitment success have long been thought to be determined within the first summer following ocean migration. Juvenile growth during this period is largely influenced by ocean conditions such as temperature, prey availability, abundance, and quality. Shifts in these conditions due to climatic perturbations are particularly prevalent...
If fisheries managers are to effectively manage commercially exploited fish populations, a basic understanding of the factors that influence fish distribution and abundance is required. In 2005, efforts to identify Essential Fish Habitat (EFH) for the 82 groundfish species managed by the Pacific Fishery Management Council along the West Coast...