Coastal Pacific hake (Merluccius productus) are known
to spawn in the southern California Bight from January
to March, migrate north during late spring and summer
to feed off Oregon, Washington, and British Columbia,
and then move back to southern California in the fall.
Juvenile Pacific hake nursery areas have been...
This study was conducted to determine the composition and size of prey consumed by northern fur seals (Callorhinus ursinus) in the eastern Bering Sea. Eighty three northern fur seals were collected in the summer and fall of 1981, 1982, and 1985 for examination of gastrointestinal contents. A total of 139...
The principal objective of this analysis is the
development of a methodological approach that would
permit a more complete evaluation of the physical and
economic consequences of prohibited species by-catch
(PSC) losses, such as occur in the harvest of groundfish.
To achieve efficient management of the several marine
species involved...
Purpose: Stereotactic radiation therapy and stereotactic radiosurgery deliver radiation precisely to tumors, using special equipment to position and demobilize patients. The VisionRT system, with its component AlignRT, is a non-invasive stereotactic positioning and tracking system that uses cameras to capture infra-red images of patients, and process these images, to obtain...
The distribution of adult Pacific herring (Clupea harengue
pallasi) near Auke Bay, Lynn Canal, southeastern Alaska, varied by
depth and geographic area over 24 successive months during 1973-75.
From June through September, schools concentrated at 5- to 37-m
depths where zooplankton was abundant, and moderate currents were
present in a...
The distribution of herring (Clupea harengus pallasi) in
the Northeast Pacific extends from southern California to
northern Alaska. Studies on variation in herring life-history
are limited to local
characteristics and recruitment
populations or relatively restricted regions of the Northeast
Pacific. In this study I assessed herring life-history
patterns and recruitment...
The Bering Sea responds rapidly to atmospheric perturbations and over the past several decades has experienced extreme variability in both its physical and biological characteristics. These changes can
impact organisms that inhabit the region, particularly marine fishes, as normal current patterns to which
reproductive habits are tuned can be disrupted,...
Radiation film dosimetry process using the RIT 113 v.4 dosimetry software and the film digitizer VXR-l2plus was used to evaluate the accuracy of electron dose calculations of the RAHD radiation therapy treatment planning system at Samaritan Regional Cancer Center. Kodak Ready-Pack EDR-2 film is recommended for dose distribution analysis in...
The aim of this work is to develop a predator-prey model for two species of commercial importance captured by the European fishing fleet in the European Grounds. In this model, the hake (Merluccius merluccius) represents the predator, and the blue whiting (Micromesistius poutassou) is the prey. Both the predator and...
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fisheries and marine
ecosystems. Science 277: 509–515.
Brown G, Berger B, Ikiara M., 2005. A Predator
Environmental variability is increasingly recognized as a primary determinant of year-class strength of marine fishes by directly or indirectly influencing egg and larval development, growth, and survival. Here we examined the role of annual water temperature variability in determining when and where walleye pollock (Theragra chalcogramma) spawn in the eastern...
Recent advancements in unmanned aerial vehicle (drone*) technology, sensors, and software applications have increased efficiency in data collection, reduced human error, and increased safety while managing a wide range of projects. No longer relegated solely to military use, drones have become synonymous with picturesque views of natural wonders and resources...
When adult spawning and juvenile settling locations of marine fishes are
geographically separated, their early life history stages must rely on transport and
their own behavior to move them toward suitable habitats for successful recruitment
to the juvenile phase. Variations in climate may reduce the availability of spawning
and juvenile...
The ecological consequences of widespread fisheries-induced reductions of large pelagic predators are not fully understood. Tropical tunas are considered a main component of apex predator guilds that include sharks and billfishes, and thus may seem unsusceptible to secondary effects of fishing top predators. However, intra-guild predation can occur because of...
Sampling error associated with estimates of species composition and age composition
of commercial groundfish landings in Oregon from 1989 to 1991 is documented to evaluate
the impact of variable landing data on fisheries management and monitoring programs. The
statistical reliability and bias associated with two multistage sampling designs are
investigated...
The majority of survival analyses focus on temporal scales. Consequently, there is a limited understanding of how species survival varies over space and, ultimately, how spatial variability in the environment affects the temporal dynamics of species abundance. Using data from the Barents Sea, we study the spatiotemporal variability of the...
The ecological consequences of widespread fisheries-induced reductions of large pelagic predators are not fully understood. Tropical tunas are considered a main component of apex predator guilds that include sharks and billfishes, and thus may seem unsusceptible to secondary effects of fishing top predators. However, intra-guild predation can occur because of...
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serve as a density-dependent
mechanism for population regulation (Anderson & Gregory 2000, Wespestad
Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic chemical compounds found in the
environment, largely as a result of partial combustion of organic compounds. PAHs are
present in the atmosphere in populated cities worldwide. Because of the health risks they
create, PAHs are a global health concern. PAHs are introduced into the...
The state of the California Current system (CCS) since spring 2010 has evolved in response to the development of cooler La Nina following the dissipation of the relatively weak and short-lived El Nino event of 2009-2010. The 2009-2010 El Nino appears to have dissipated quite rapidly in early spring 2010,...
This report reviews the state of the California Current System (CCS) between winter 2012 and spring 2013, and includes observations from Washington State to Baja California. During 2012, large-scale climate modes indicated the CCS remained in a cool, productive phase present since 2007. The upwelling season was delayed north of...
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, K. M., S. Ralston, and V. G. Wespestad. 2006. Interannual and spatial
variation in the distribution
There is growing evidence that climate and anthropogenic influences on marine ecosystems are largely manifested by changes in species spatial dynamics. However, less is known about how shifts in species distributions might alter predator-prey overlap and the dynamics of prey populations. We developed a general approach to quantify species spatial...
The energy budget of a pumice desert surface was analyzed under clear skies during early, mid-and late summer periods. The pumice site is in the semi-arid plateau region of Central Oregon at an elevation of about 1500 meters. The flat pumice surface is approximately 250 hectares in extent, and is...
The Pacific coast groundfish fishery is a diverse, important and lucrative commercial and recreational fishery. Part of this fishery’s monitoring process includes regular fishery-independent surveys for stock assessment. Although these fishery-independent surveys are cost-effective, they are susceptible to scientific uncertainty, and they do not currently sample in nearshore (water depth...
The state of the California Current System (CCS)
since spring 2011 has evolved in response to dissipation
of La Niña through spring and summer, resurgence of
cooler La Niña conditions in fall and winter, and finally
a transition towards ENSO-neutral conditions in spring
2012. The resurgence of La Niña was...
In this work we consider a mathematical and computational model for biofilm growth and nutrient utilization. In particular, we are interested in a model appropriate at a scale of interface. The model is a system of two coupled nonlinear diffusion--reaction partial differential equations (PDEs). One of these PDEs is subject...
The taxonomic composition, distribution, concentration, and community structure of ichthyoplankton off the Oregon and Washington coasts were examined in 2004-2009 to investigate annual, seasonal, latitudinal, and cross-shelf variability. Larval concentrations and community structure were also analyzed in relation to several local and larger-scale environmental variables. The dominant taxa, comprising 94%...
Large river plumes modify coastal environments and can impact production across multiple trophic levels. From 1999 to 2009, the
assemblages of forage fish, predator fish, and other pelagic nekton were monitored in coastal waters associated with the Columbia
River plume. Surveys were conducted at night to target vertically migrating species,...
Variable ocean conditions can greatly impact
prey assemblages and predator foraging in marine ecosystems.
Our goal was to better understand how a change in
ocean conditions influenced dietary niche overlap among
a suite of midtrophic-level predators. We examined the
diets of three fishes and one seabird off central Oregon
during...
Northern anchovy (Engraulis mordax) are a dominant forage fish in the California Current large marine ecosystem (CCLME). However, little is known about northern anchovy abundance, distribution, age structure, or population fluctuations relative to ocean conditions in the eastern boundary upwelling system off the U.S. West Coast. This thesis includes three...
Food sovereignty is increasingly being conceptualized as a human rights issue. This is evidenced in the growth of local actors, communities, and nation-states that are working towards a food sovereignty agenda. Indicators of food sovereignty center on people having the right and ability to define their food polices. One of...
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...
Fishing firms in Oregon operate in a complex and dynamic physical, biological and institutional environment. Within this environment, managers of these firms will attempt to maximize some objective function which may include profit. This maximization is dependent upon the level of output, or the levels of inputs. Given a relationship...
A fully-saturated poroelastic medium is confined by the sides of a cylinder, and the regions below and above the medium are filled with fluid at respective constant pressures. The filtration flow of fluid through the poroelastic medium and the small deformations of the medium are described by a quasi-static Biot...
A constant temperature anemometer, utilizing quartz coated hot
film probes, was used to measure velocities from .1 to 5 cm/sec.
The effects on anemometer performance due to time, reimmersion,
and metallic sensor coatings were examinated by repeated calibrations
of the probes. Contrary to previous published results, calibration
change due to...
The Northern California Current (NCC) is a seasonally productive and open ecosystem. It is home to both a diverse endemic community and to seasonally transient species. Productivity and food web structure vary seasonally, interannually, and decadally due to variability in coastal upwelling, climate-scale physical processes, and the migratory species entering...
Under simulated accident conditions, tees in the primary coolant loop of a Pressurized Water Reactor (PWR) can deviate from their original design purpose and become separators that effectively remove core heat sink capacity. This method of primary coolant removal is a phenomelogical subset of phase separation known as liquid entrainment,...
Recent research conducted throughout the Northern California Current (NCC) on the ecology of Pacific salmon (Oncorhynchus spp.) indicates that variable ocean conditions affect the community composition of zooplankton in the nearshore environment which, in turn, can affect the quality of prey for fish, sea birds and mammals. Interannual variability in...
In this dissertation we develop mathematical treatment for two important applications: (i) evolution of methane in coalbeds with the associated phenomena of adsorption, and (ii) formation of methane hydrates in seabed. We use simplified models for (i) and (ii) since we are more interested in qualitative properties of the solutions...
Cooperative marine fisheries research—the practice of involving the expertise of fishermen and scientists in conducting studies of ocean fishes—has increased gradually over the past 50 years on the US west coast. However, few studies have systematically collected and analyzed the experiences and perceptions of numerous cooperative marine fisheries research project...
Heat transfer from a vertical flat plate in an infinite pool of
mercury was investigated. Velocity profiles were measured with a
hot-film anemometer and simultaneous temperature profiles measured
with thermocouples in this low Prandtl number liquid metal. Constant
heat flux plates at Grashof numbers of 9 x 10⁸ and 4...
The current trend toward the establishment and care of forests for a
wide combination of uses requires flexibility in forest culture and a
knowledge of the silvicultural choices available to the resource manager. This
publication summarizes for each of 37 major forest types in the United States
the silvicultural systems...
Tropical coral reef ecosystems are very important from both the ecological and economical
points of view. However, they are also particularly fragile, and have been
declining in recent years in most regions of the world, since they are highly susceptible
to anthropogenic stressors operating at global scales (e.g., global warming...
The average size and age of chinook salmon (Oncorhynchus
tshawytscha) caught in commercial fisheries along the Pacific Coast
of North America have decreased substantially in this century. These
declines might be caused in part by changes in size and age at
maturity within the stocks contributing to those fisheries. Upriver...
Published July 1987. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
The group of scientists that make up the Intergovernmental Panel on Climate Change found in 2007 that the warming of Earth’s climate is unequivocal and largely due to human activity. Earth’s climate has changed in the past, though the recent magnitude and pace of changes are unprecedented in human existence....