Plasma concentrations of cortisol, a glucocorticoid hormone that
is immunosuppressive in mammals, increase during stress and
smoltification of salmonids. There was a reduction in the ability of
lymphocytes to generate antibody producing cells (APC) in vivo
concurrent with increased plasma cortisol titers during smoltification
of coho salmon (Oncorhvnchus kisutch). Cortisol...
Juvenile chinook salmon (Oncorhynchus tshawytscha) were experimentally infected with Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease (BKD), to investigate the effects of BKD on three aspects of juvenile salmonid performance: (1) predator avoidance ability; (2) smoltification; and (3) physiological responses to stress. For these experiments, fish with...
Electrofishing is a sampling tool commonly used by fisheries researchers. While much is known about the effects of electroshock on fish physiology, consequences to the immune system and disease progression have not received attention. To understand the effects of electroshock on immune function we undertook a comparison of electroshock and...
Nearly 3000 juvenile Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon captured in nearshore waters off the coasts of Washington and Oregon from 1999-2004 were tested for infection by Renibacterium salmoninarum, Nanophyetus salmincola, and skin metacercariae. First, three quantitative PCR primer/probe sets were compared for detection of R. salmoninarum; amplification...
DNA segments in the fungus Fusarium graminearum were identified as possible genes encoding for chromodomain proteins (CDPs), and targeted for genetic manipulation. Targeted single-gene deletion strains, as wells as GFP-S tag fusion strains, were generated from wildtype F. graminearum protoplasts, and verified strains were screened for phenotypic differences, such as...
Full Text:
graminearum Through Targeted Genetic Manipulation
by
Alec J. Peters
A PROJECT
Submitted to
Oregon
Although much is known about the effects of electroshock on fish physiology, consequences to the immune system and disease progression have not received attention. Our objectives were to determine the effects of electroshock on selected immune function in juvenile spring chinook salmon Oncorhynchus tshawytscha, the mechanism of any observed alteration,...
If wind power is to become a viable energy alternative, a rapid and reliable cost effective methodology must be established, whereby large areas can be surveyed for windy sites and those sites can be evaluated. Based primarily on locating wind deformed vegetation, this paper establishes the feasibility of using air...
Ornamental landscapes require considerable amounts of inputs, including but not limited to irrigation, mowing or pruning, fertilization, and pest management. However, school systems have limited budgets, which reduce their access to resources and labor hours. Therefore, the objective of this project is to identify ground covers that can compete with...
Currently, fungicide applications are the predominant method of control for the cool weather pathogen Microdochium patch (Microdochium nivale). Increasing pesticide restrictions have generated concern regarding management of Microdochium patch. Three separate field trials exploring non-traditional fungicides were conducted between 2013 and 2015 on an annual bluegrass (Poa annua L.) sand-based...
Managing Microdochium patch on intensively manicured annual bluegrass putting greens is a challenge for turfgrass professionals in cool-humid climates similar to the Pacific Northwest. Fungicides are the predominant means to mitigate damage caused by this fungal pathogen, however pesticide restrictions are making it even more challenging to suppress Microdochium patch....
Annual bluegrass (Poa annua L.) is a prolific annual grassy weed that can be found worldwide in most landscapes. Known for its ability to produce seedhead at low heights (0.32 cm), thrive in over-maintained areas, and germinate anywhere, annual bluegrass is a highly invasive weed. Due to annual bluegrass’ persistence,...
:
____________________________________________________________________
Alec R. Kowalewski
Annual bluegrass (Poa annua L.) is a prolific annual grassy weed that can
We evaluated the effects of the McNary Dam transportation system on emigrating fall and spring chinook smolts using physiological indices of stress (e.g., plasma cortisol, hepatic glycogen, leucocrit, interrenal cell nuclear diameter) and performance tests (e.g., saltwater challenge, secondary stress challenge, disease resistance). We also conducted controlled experiments in a...
Cyanophage are viruses that infect cyanobacteria, photosynthetic microorganisms which are known to produce several anticancer and antibacterial chemical compounds. Cyanophage are significant members of microbial communities in marine and freshwater environments. There has been significant difficulty inventorying marine and freshwater cyanophage, however, due to the difficulty in cultivating their hosts....
Full Text:
Alec Vallota-Eastman1, Kerry McPhail2, Rebecca Vega-Thurber3
Bioresource Research1, College of
Cyanophage are viruses that infect cyanobacteria, photosynthetic microorganisms which are known to produce several anticancer and antibacterial chemical compounds. Cyanophage are significant members of microbial communities in marine and freshwater environments. There has been significant difficulty inventorying marine and freshwater cyanophage, however, due to the difficulty in cultivating their hosts....
Full Text:
marine cyanophage as revealed
by sequence analysis of various phage marker genes
Alec Vallota-Eastman1
DNA segments in the fungus Fusarium graminearum were identified as possible genes encoding for chromodomain proteins (CDPs), and targeted for genetic manipulation. Targeted single-gene deletion strains, as wells as GFP-S tag fusion strains, were generated from wildtype F. graminearum protoplasts, and verified strains were screened for phenotypic differences, such as...
Generative programming is a paradigm that seeks to automate the manufacture of software products the same way other industries automated the manufacture of consumer, electric, and mechanical products. I examine how meta-programming fits into the context of generative programming and, along the way, expose theoretic and taxonomic deficiencies. In some...
Tracking footwear wear patterns is vital to the footwear industry. In the game of tennis, there are several court surfaces that produce unique wear patterns on footwear that are constantly changing according to the following factors: level of competition, level of experience, coordination, age, height, weight, and more. By tracking...
The Interactive Virtual Laboratories (IVLs) are a series of two-dimensional simulations designed to help students conceptually learn difficult concepts in thermodynamics. Three studies were performed to help elucidate how the IVLs affect student learning. In the first study, eight students were observed while completing one of the IVLs. The students...
California brome and blue wildrye are important native grass species in the Pacific Northwest. However, both species have been reported to have low emergence under less than favorable field conditions. Seed coating is used to improve emergence and stand establishment of various crops. Three studies were carried out to determine...
This report describes results of the third year of an evaluation of the online presence and prices of companies on the Oregon coast that offer tours for kayaking, salmon fishing and whale watching. It also compares those 2019 results with findings from 2017 and 2018. Our aim was to see...
Roughstalk bluegrass (Poa trivialis L.) (RB) is a weed species that increased very quickly in grass seed production fields of the Willamette Valley. The invasion of RB in grass seed crops often occurs in waterlogged soils. In waterlogged areas, RB exhibited better competitiveness and had greater population densities than other...
Livestock grazing is the prominent land use in Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis [Beetle & A. Young] S.L. Welsh) steppe and has been present since the late 1800’s. There have been calls to remove livestock grazing from rangelands as historic grazing practices resulted in the degradation of some...
The agricultural industry in the Western United States continues to possess issues of overwatering, accounting for over 80% of consumed water per year in the country. While technologies such as satellite imaging and sensor networks have slowly improved irrigation Best Management Practices to reduce superfluous water consumption, limitations associated with...
Although the potato (Solanum tuberosum L.) is a global crop, few growing regions rival the high yields of the Columbia Basin of Eastern Oregon and Washington. Two research projects were conducted in Hermiston, OR to contribute to best management practices for the region. The first project evaluated the efficacy of...
Within the sagebrush steppe ecosystem, invasive annual grasses are of growing management concern as they outcompete native vegetation, change the fundamental nutrient cycling processes, decrease biodiversity, and increase frequency of wildfires. The most widely used and effective management tool to decrease invasive annual grass abundance, is the use of pre-emergent...
Perennial ryegrass (Lolium perenne L.) is a widely grown cool season, bunch type, short lived perennial grass that is native to Europe, Asia, and North Africa, but has been adapted globally. Perennial ryegrass is quick to establish, has a long growing season, and produces high seed yield and forage or...
Describes options for different levels of lawn care – from keeping a lawn lush and green year-round to allowing it to go partially dormant in the summer. Discusses mowing, watering, fertilizing, and dethatching, and gives recommended schedules for each. Includes a list of additional resources.
Seashore paspalum (Paspalum vaginatum Sw.) is an important warm-season perennial turfgrass, known for its tolerance to salinity. Turfgrass is used for homes, municipalities, sod farms, resorts, and sports fields. Seashore paspalum has historically been planted in sub-tropical and tropical climates because of its heat tolerance. Seashore paspalum could become an...
Phytophthora cinnamomi is a soilborne pathogen that causes root rot disease of highbush blueberry (Vaccinium corymbosum L.). When new installations of susceptible blueberry cultivars are infected with P. cinnamomi, plants often fail to grow significant new tissue, greatly reducing yields over the life of the planting. Chemical fungicides are available...
We describe spatio-temporal random processes using linear mixed models and discuss estimation, inference, and prediction under this formulation. We show how many commonly used covariances are special cases of this more general framework and pay special attention to the separable and product-sum covariances. The linear mixed model formulation facilitates straightforward...
The literature on first-generation South Asian American (SAA) mental health is limited despite the increased focus of studies on help-seeking behaviors and subjective well-being over the past decade. Therefore, we designed a web-based survey seeking to address two research questions. Research Question 1 informed Study 1 of this dissertation project:...
Reestablishing native perennial vegetation in annual grass-invaded rangelands is critical to restoring ecosystems, especially following wildfires. Controlling invasive annual grasses is essential to increasing revegetation success; however, pre-emergent herbicides used to control annual grasses prohibit immediate seeding due to non-target herbicide damage. Thus, seeding is often delayed one year following...
The body of work aims to contribute to the area of Quantitative analysis in Environmental Sciences, and is focused on the microbiome. The underlying theme for the dissertation is methods and workflow. The unique bioinformatics workflow used for the analysis of genomic data was used to answer distinct and pressing...
Mental health disorders are the leading cause of disability worldwide. The strong need for mental health services has prompted intensive global efforts to develop, evaluate, and deliver effective mental health treatment, especially for low- and middle-income countries. The counseling profession in the United States has responded to this global need...
This study aims to improve knowledge of how suspended particulate matter (SPM) affects hydrophobic contaminant transport in the lower Columbia River and its estuary, using polycyclic aromatic hydrocarbons (PAHs) as model compounds. It is hypothesized that PAHs are transported to the estuarine turbidity maximum (ETM), a prime feeding zone in...
:
________________________________________________________________________
Fredrick G. Prahl
This study aims to improve knowledge of how suspended particulate matter
The purpose of this study was to explore the lived experiences of school-based agriculture education (SBAE) teachers who self-identified as blended pedagogues. This study specifically focused on SBAE teachers' beliefs and how those beliefs influence their blended teaching classroom practice. Teacher beliefs are personal, subjective, and temporally and contextually stable....
We examined the behavioral and physiological responses of wild
and hatchery-reared cutthroat trout Oncorhynchus clarki subjected to
a single electroshock, electroshock plus marking, and multiple
electroshocking in natural and artificial streams. In a natural
stream, trout released after capture by electrofishing and marking
showed distinct behavioral changes: fish immediately sought...
The long duration and strong velocity content of the motions produced by the 27 February 2010 Maule earthquake resulted in widespread liquefaction and lateral spreading in several urban and other regions of Chile. In particular, critical lifeline structures such as bridges, roadway embankments, and railroads were damaged by ground shaking...
Hatcheries whose purpose is to provide for a recreational fishery must minimize impacts on wild fishes. Management to reduce hatchery and wild interactions is especially important on river systems that contain Endangered Species Act (ESA) listed species. I examined adult hatchery summer steelhead, Oncorhynchus mykiss, behavior, current management and a...
One important cool-season perennial grass seed crop grown in Oregon is fine fescue (Festuca rubra L.). Open-field burning has been used for many decades to manage pests, cycle nutrients, and stabilize yield, in fine fescue seed fields, especially as stands age. Legislative restrictions currently limit open-field burning to 6,070 hectares...
Recently concerns over anthropogenic carbon pollution have received increased global attention and research in forest biomass and carbon sequestration has gained momentum. Light Detection and Ranging (LiDAR) remote sensing has in the last decade demonstrated forest measurement and biomass estimation potential. The project objective was to compare LiDAR forest biomass...
The bioavailability of chemical compounds in the marine environment fundamentally influences the growth and physiology of microorganisms. Organic and inorganic chemicals that are produced by some marine plankton can be consumed by other plankton for energy production, growth, or to initiate essential physiological processes. Cultures of the diatom Thalassiosira pseudonana,...
Numerous fishery researchers have attempted to preserve viable fish sperm, but only three investigations were successful in the fertilization of fresh eggs with frozen and thawed sperm: Blaxter (1953); Hoyle and Idler (1968); and Graybill and Horton (1969). Significant advances reported in this thesis were: the development of suitable life...
Studies on prison contracting have typically focused on the privatization of entire facilities and carceral services offered to inmates. There has been limited research, however, as to how political ideology influences the extent to which state prisons contract out health care services. There also appears to be a need for...
This dissertation is a qualitative secondary content analysis of clinical records collected for the Spokane Safe Start Project in Spokane, Washington, a program designed to offset trauma in children exposed to domestic and intimate partner violence (IPV). The Centers for Disease Control and the World Health Organization have identified intimate...
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...
Combinations of cohesive and cohesionless soils are often encountered
when evaluating the engineering properties of soils. The
stress-volume characteristics of the mixed soil are found to vary according
to the proportion of each component. If the cohesive soil
composes more than a certain fraction of the material, the magnitude
of...
Studies were conducted to evaluate the use of several trap-lure combinations to improve the monitoring of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), in apple, Malus domestica Bordk. The treatments involved the use of clear, orange, and white traps baited with one or more of the following attractants: the major...
We evaluated genes previously identified from a large scale functional genomics screen for their potential value to help enhance carbon sequestration in planted trees. We used poplar as a model tree species because of its abundant genetic variation, ease of gene transfer, and availability of large databases for genomic, anatomical,...
Anomaly detection has been used in variety of applications in practice, including cyber-security, fraud detection and detecting faults in safety critical systems, etc. Anomaly detectors produce a ranked list of statistical anomalies, which are typically examined by human analysts in order to extract the actual anomalies of interest. Unfortunately, most...
To investigate the dynamic response of the outer accretionary wedge updip from the patch of greatest slip during the Mw8.8 2010 Maule earthquake, 10 Ocean Bottom Seismometers (OBS) were deployed from May 2012 to March 2013 in a small array with an inter-instrument spacing of ~10 km. Nine instruments were...
Stem sinuosity is a highly visible stem-form trait in the leaders of fast-growing Douglas-fir (Pseudotsuga menziesii var. (Mirb.) Franco) trees, yet its cause is unknown. We tested the hypotheses that sinuous stems have longer expanses of primary growth than nonsinuous stems (putting the leader at higher risk curvature, induction of...
15161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293
S
e
c
o
n
d
a
ry
g
ro
w
th
(c
m
)
0
10
20
30
40
50
60
The south central Chilean margin is one of the most seismically active subduction zones on Earth, generating some of the largest earthquakes on the planet, including the largest ever recorded in 1960 near Valdivia, Chile (Mw 9.5). Using the 15 km streamer and 6600 in3 tuned seismic airgun array aboard...
The lack of availability of a single, complete paper on the
analysis of a digital data acquisition system for in situ oceanographic
measurements brought about the present work. In order to compile
an accurate technical paper on such a complex system, it was necessary
to design, construct, and calibrate a...
The climate of the Pacific Northwest is in flux, and existing forest ecosystems are stressed and poised to shift in fundamental ways, with or without human intervention. This dissertation probes the nature of forest responses to environmental change through investigations of morphology and genetics of three species of alder co-occurring...
Stress, including extreme or rapidly changing temperatures, are known to have deleterious effects on fish health and physiology. This thesis examines the combined effects of elevated acclimation temperature and acute handling stress on the number of antibody producing cells, plasma lysozyme concentrations, and the number of pronephric leukocytes in juvenile...
Environmental factors such as chemical contamination can have immunomodulatory effects on the immune response of fish and may be contributing to the decline in salmonid populations by augmenting disease susceptibility. Xenobiotics can interfere with the immune system at several levels of complexity, and different immune cells and processes have variable...
Hop tissue (Humulus lupulus L.) was grown in vitro in
callus, suspension, and protoplast cultures. Medium
components were evaluated for optimal callus growth.
Solid Murashige and Skoog (MS) medium with picloram at 1.5
uM, 6-benzylaminopurine (BAP) at 10 uM, 1 g/1 casein
hydrolysate, and 100 mg/1 citric acid induced white,...
A large number of river otter (Lontra canadensis) males were collected
from areas of high and low contaminant concentrations throughout western
Oregon and Washington during the fall and winter of 1994-99. Few significant
non-reproductive organ morphometric differences were found in the large series
of male otters collected, except for adrenal...
A large number of river otter (Lontra canadensis) males were collected
from areas of high and low contaminant concentrations throughout western
Oregon and Washington during the fall and winter of 1994-99. Few significant
non-reproductive organ morphometric differences were found in the large series
of male otters collected, except for adrenal...
A simple behavioral test was devised to determine the effects of multiple acute stresses on the avoidance response time of fish. Groups of freshwater-adapted juvenile chinook salmon Oncorhynchus tshawytscha were exposed to a sudden overhead light and the time it took each fish to reach cover was noted. Tests were...
The infection intensity of the monogenetic trematode Gyrodactyus stellatus on laboratory held English sole (Parophrys vetulus) appeared to be influenced by handling stress, substrate, and starvation. In bioassays testing G. stellatus survival times in mucus and serum collected from laboratory held sole at different times during trematode infection, trematode survival...
Various methods have been developed to mitigate the adverse effects of the Federal Columbia River Power System on juvenile Pacific salmon out-migrating through the Columbia River basin. In this study, we found that hatchery-reared spring Chinook salmon Oncorhynchus tshawytscha in the river are in varying degrees of health, which may...
Foodborne outbreaks involving fresh produce have been on the rise since the late 1990's. Pathogens such as Salmonella spp. and Escherichia coli are prevalent in agricultural environments and commonly travel between farms via irrigation water. The Food Safety Modernization Act (FSMA) has placed an increased emphasis on microbiological standards of...
Identification of the factors that influence susceptibility to predation can aid in developing management strategies to recover fish populations of conservation concern. Predator-prey relationships can be influenced by numerous factors, including prey condition, prey size, and environmental conditions. We investigated these factors by using juvenile steelhead Oncorhynchus mykiss from the...
Across animal taxa, migration allows individuals to exploit habitats and resources that predictably vary seasonally in suitability. Theory predicts that the ‘‘decision’’ to migrate or not is shaped by the relative fitness costs and benefits of exhibiting a given life history. Adoption of a migratory strategy is widely thought to...
Ocean circulation is an important component in Earth's climate system. Predicting future climate and circulation changes requires an improved understanding of the past relationship between climate and ocean currents. The neodymium isotope composition (εNd) of water masses is frequently used as a quasi-conservative tracer to reconstruct ocean circulation. The current...
Research Summary: Private correctional firms are political actors. They work to create favorable conditions to market their services. At the same time, they are constrained by external political forces, including political parties, social movements, and public opinion. This article reviews what we know about the reciprocal relationship between the private...
Freshwater discharge affects the biogeochemistry of river-influenced nearshore environments by contributing with carbon and nutrients. An increase in human activities in river basins may alter the natural riverine nutrients and carbon export to coastal ecosystems. Along a wide latitudinal range (32° 55'S-40° 10'S), this study explores the role of climate...
Selected life history aspects of American shad, Alosa
sapidissima, collected in Lake Umatilla of the Columbia River
during 1980 and 1981 were examined and compared to other shad
populations. Mean fork lengths of adult shad captured in
1981 were 405-, 415- and 423-mm for age III, IV and V males;...
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...
Pacific whiting and its by-products were good raw materials for high quality fish sauce production. Heat stable and salt activated enzymes were responsible for autolytic activity in Pacific whiting and by-products. According to temperature profiles of raw materials at various salt concentrations, two fermentation temperatures, 35°C and 50°C, were selected...
The operation of the Federal Columbia River Power System (FCRPS) has negatively affected threatened and endangered salmonid populations in the Pacific Northwest. Barging Snake River spring Chinook salmon Oncorhynchus tshawytscha through the FCRPS is one effort to mitigate the effect of the hydrosystem on juvenile salmon out-migration. However, little is...
Four experiments were conducted to determine oxytocin concen tration of bovine luteal tissue at different stages of the estrous cycle and to study the effects of prostaglandins F₂α (PGF₂α), E₂ (PGE₂), luteinizing hormone (LH), cycloheximide, colchicine and cytochalasin B on oxytocin synthesis and release in vitro. In experiment 1, luteal...
Intercellular transport of viruses through cytoplasmic connections, termed plasmodesmata (PD), is essential for systemic infection in plants by viruses. Previous genetic and ultrastructural data revealed that the potyvirus cyclindrical inclusion (CI) protein is directly involved in cell-to-cell movement, likely through the formation of conical structures anchored to and extended through...
Subduction zone earthquake and tsunami hazards affect tens of millions worldwide and the recurrence of these disasters can be evaluated with paleoseismic techniques, because earthquake cycles (and their supercycles) typically span many millennia. In these three chapters, I discuss a suite of analyses I use to evaluate the sedimentary record...
Full Text:
, I es mate that slopes become unstable when a seismic
load of <0.2 g is imparted. Using infi nite
The in vitro effects of cortisol in regulating salmonid B cell functions were
investigated. B cells at three distinct stages of differentiation were examined for
cortisol sensitivity. B lymphocyte responses were examined 1) during the early stage
of the precursor, 2) during the intermediate stage of differentiation associated with
clonal...
Lateral spread is a pervasive type of liquefaction-induced ground failure that occurs on gentle slopes or near free-faces, such as river channels. Resulting horizontal displacements can reach up to several meters, and can be considerably damaging to foundations, bridges, roadways, pipelines, etc. In the 1990s, Bartlett and Youd (1992a, 1995)...
Current bridge design codes do not account for the effects of duration of mega-thrust subduction zone earthquakes. Furthermore, codes and even recent performance-based design methodologies only make use of the peak response quantities (forces, displacements, and ductility demands) and do not account for the increased number of inelastic cycles that...
Experiments were designed to determine whether and how steelhead Oncorhynchus mykiss affect chinook salmon O. tshawytscha when the two species are confined together. In a behavioral experiment, we observed groups of juvenile chinook salmon and steelhead together and groups of chinook salmon alone to determine whether the steelhead were aggressive...
Wild populations of fish are faced with a multitude of stressors, which may include human interaction, toxins, and disease. Benzo(a)pyrene (BaP), a known carcinogen and immunotoxin, has been reported in the stomach contents of juvenile chinook salmon, Oncorhynchus tshawytscha, in urban waterways. We investigated the impact of chronic dietary exposure...
The relationship between predator avoidance deficits induced by a simple handling stress and the level of plasma corticosteroids was determined for juvenile coho salmon Oncorhynchus kisutch. Groups of fish were held out of water for 1 min, then allowed to recover from this stress for 1, 90, or 240 min....
Genetic, ontogenetic, and environmental factors modified characteristic interrenal and glycemic responses to stress in juvenile salmonid fishes. During continuous confinement stress, plasma cortisol rose more quickly in chinook salmon, Oncorhynchus tshawytscha, acclimated to high rather than medium or low temperatures; hyperglycemia following either acute or chronic stress was also highest...
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...
As a major biological model for biomedical research, maintaining healthy
zebrafish (Danio rerio) is imperative for accurate and consistent lab results. This
retrospective study focuses on Pseudoloma neurophilia, a microsporidium, because it is
the most common pathogen found in laboratory zebrafish. An online database maintained
by the Zebrafish International Resource...
Once historically widespread throughout the Willamette and Umpqua
River drainages, the Willamette Oregon chub is now restricted to
scattered populations along 15 miles of the Middle Fork of the
Willamette River whereas the Umpqua Oregon chub is still widely
distributed. The decline in the Willamette drainage was more severe
because...