In the Pacific Northwest, several species of rockfishes (Sebastes spp.) are under extreme conservation measures due to low population levels. Although currently at healthy population levels, one species of interest is the black rockfish (S. melanops), which has been shown to utilize estuarine habitat during its early life history stages....
Human alterations of landscapes take many forms, one of which is anthropogenic pollution. Mercury (Hg) is a complex contaminant because its uptake into the food web is not driven entirely by loading to the system; methylation is necessary to make Hg bioavailable and toxic to fish and wildlife. Because methylation...
The 1988 status of yellowtail flounder stocks off the U.S. coast
of the Northwest Atlantic is assessed using U.S. and distant water
fleet commercial fishery statistics and Northeast Fisheries Center
bottom trawl survey data. Assessments of Southern New England and
Georges Bank stocks are revised using virtual population analysis of...
Early ocean residence is assumed to be a critical period for juvenile Pacific salmon Oncorhynchus spp. However, the specific mechanisms influencing growth and survival in the ocean have not been identified for most populations. Therefore, three hypotheses regarding the relationship between early marine residence and subsequent survival of mid-upper Columbia...
Several dolphin species have global distributions. The extent of their radiation and limits to gene flow are presumably a product of oceanographic features both recent and historical, behavioral specializations and social organization. Rough-toothed dolphins (Steno bredanensis) are globally distributed in tropical and subtropical waters and are generally found in depths...
Natural and gabion modified habitats containing coho salmon
(Oncorhynchus kisutch) were observed and measured seasonally in East
Fork Lobster Creek, a fifth order stream in western Oregon. Coho
salmon usually inhabited backwater and secondary channel pools in
winter. Large wood debris complexes and undercut banks were the
primary sources of...
Isotope and stomach content data from piscivorous reservoir fishes collected from Hills Creek (isotopes; 43°40′16″N 122°25′33″W) and Lookout Point (isotopes and stomach contents; 43°53′48″N 122°43′34″W) reservoirs located on the Middle Fork Willamette River, Oregon. Additional details can be found in the related publication.
Isotope sampling was conducted under OSU Institutional...
The ultimate goals of this project are to 1) provide farmers with data-based advice on maintenance and enhancement of habitat for native wildlife based on what species are using the remnant/unfarmed patches on producers farms and to 2) provide background knowledge and data to enable development of a larger project...
The Pigeon Guillemot (Cepphus columba) is now the only species of marine bird in Prince William Sound (PWS), Alaska that is listed as "not recovering" on the Exxon Valdez Oil Spill (EVOS) Trustee Council's Injured Resources List and has shown no sign of population recovery. During the 20 years since...
Habitat loss causes a reduction in available resources for wildlife, alters the configuration of remaining habitat, and may isolate wildlife populations. White-breasted nuthatches (Sitta carolinensis) are experiencing long-term population declines in the Willamette Valley of Oregon, where they are historically associated with oak woodlands. As secondary cavity-nesters, white-breasted nuthatches may...
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...
Infectious pancreatic necrosis (IPN) is an acute, contagious disease of trout fry
and fingerlings caused by viruses of the family birnaviridae. IPN disease usually results
in mortality that is inversely proportional to the age of the fish. While many studies
have been carried out to increase our understanding of IPN,...
Differences in the chemical composition of calcified structures can be used to reveal natal origins, connectivity, metapopulation structure, and reconstruct the environmental history or movement patterns of many marine organisms. Sharks, skates, and rays (elasmobranchs) lack the calcified structures, known as otoliths, that are typically used for geochemical studies of...
Anthropogenic land use alterations such as livestock grazing and fire
suppression have greatly altered sagebrush grasslands of the Great Basin,
facilitating invasion of exotic annuals, increases in woody species, and losses of
native species. Much of the current research surrounding wildland and prescribed
fire in sagebrush dominated ecosystems has focused...
Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions of people. They are some of the most vulnerable ecosystems in the United States and have been altered by human activities such as livestock...
The quality and availability of forage fishes and invertebrates can affect the behavior and productivity of predators that rely on these resources. This study measures the proximate composition of forage fishes and invertebrates from the southeastern Bering Sea to estimate prey energy density (quality) using a method that is ecologically...
Genetic differences between early and late forms of
Alaskan chinook salmon (Oncorhynchus tshawytscha) were
identified using two genetic approaches: mitochondrial
DNA (mtDNA) analysis and protein electrophoresis. The
study populations consisted of early- and late-run chinook
salmon in each of the Kenai and Kasilof rivers in Alaska,
and a single population...
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...
Models are commonly used to assess and predict wildlife response to management practices. Model validation is essential if managers are to use them with confidence. Fifteen forest bird-habitat relationship models were developed by biologists using data collected from private forestland in southwest Washington. These models predict species' probability of occurring...
Protein microcapsules (PM) were developed as a tool for investigating aspects of dietary protein utilization by mussels, Mytilus edulis trossulus. Digestion of PM in vitro by protease, trypsin, amylase and extracts from the gut of mussels varied significantly depending on the type of protein encapsulated or whether carbohydrates were added...
Spatial capture-recapture (SCR) is employed for estimating abundance and density of species, particularly those that are cryptic or solitary, and evaluating how population density varies with habitat. However, it is uncertain whether estimates are biased when applied to species that aggregate, such as elk (Cervus canadensis). Wildlife managers in the...
One fundamental concern in conservation biology is species abundance. For many taxa, however, these data are costly to obtain via direct observation and thus limited in geographic or temporal scope. Very high-resolution satellite imagery provides a means to address these limitations and provide remotely-sensed counts of large, colonial species. We...
2018 Library Undergraduate Research Awards nomination materials, reflective learning essay, and research paper.
In this study, pocket gopher and gray-tailed vole holes and hills were counted within four distinct habitats using quadrats and a gridding method over a period of five field days. The study was conducted to determine which...
Pacific sardines (Sardinops sagax) are an economically and ecologically important forage fish which transfer energy from planktonic primary producers and secondary consumers to upper trophic predators. Previous genetics studies of Pacific sardine suggested a panmictic population with a shallow genetic structure. However, more than one subpopulation within the Central California...
Species associations of fifteen major commercial groundfish species in the
northeastern Pacific ocean and their spatial and temporal characteristics were studied
using Oregon bottom trawl logbook data, 1987 to 1993. Screening procedures were used
to remove questionable data from the original logbook files, which resulted in the
exclusion of information...
Pollination is an essential ecosystem service that sustains functioning ecosystems and aids in food production. In response to recent, widespread declines of managed and native bee populations, many land managers have shown interest in developing conservation and restoration plans for enhancing native bee habitat. However, there is a lack of...
Land-use change, particularly in the form of the conversion of primary forest to forest-matrix systems, alters species communities and species interactions. Describing these often complex and nuanced species responses is one of the great challenges in ecology. Another complementary challenge is finding and using the most efficient means for collecting...
Global warming is progressing more rapidly in polar-regions, and its effects are
more pronounced at high latitudes than in other parts of the globe. Changing ocean
conditions due to climate change are predicted to have dramatic impacts on marine foodwebs.
Seabirds, as upper trophic-level consumers, provide a highly visible and...
Relative use by pronghorns (Antilocapra americana) of 16 range sites was studied during summer and fall of 1971 and 1972 on Hart Mountain National Antelope Refuge, an area of high desert
rangeland in south central Oregon. A Relative Use Index was developed based upon 1533 observations of pronghorns located on...
Reported are results of a study of otolith nuclei as a means to separate juvenile steelhead trout (Salmo gairdneri) from juvenile rainbow trout (S. gairdneri) which co-exist in the lower Deschutes River, Oregon. An intensive recreational fishery necessitated development of a technique for separation so that the impact
of the...
Determining age in crustaceans is inherently imprecise because they molt
periodically and do not retain hard structures throughout their lifespan. Morphological
measurements, such as carapace length, are often used to estimate age because
methods for direct ageing do not exist. However, variability in individual growth rate
and molt frequency can...
Ungulate behavior has been studied extensively but direct observation of free-ranging animals over long periods of time and large geographic areas is often prohibitively difficult. Improved technology, such as GPS collars fitted with motion-sensitive activity monitors, provides researchers with a potential tool to remotely collect fine scale activity and location...
The social sciences are increasingly used in conservation to describe interactions and relationships between humans, wildlife, and ecosystems. Scientists and policy-makers have concluded that promoting human tolerance for wildlife is critical to the success of conservation efforts. Yet, the concept of tolerance is relatively new in the context of human-wildlife...
Over the last 50 years, riparian zones in the semi-arid West have gained recognition as disproportionately important habitats for both breeding bird communities and agricultural operations. Despite growing interest in exploring avian-habitat relationships in these systems to better inform land management, few studies have attempted to describe temporal changes in...
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...
The Northern California Current (NCC) ecosystem exhibits extreme seasonal, interannual and interdecadal shifts in the abiotic environment and shifts in primary and higher production. This variability is also apparent in the spatial structure of the ecosystem with nearshore-shelf waters (<150 m isobath) being highly productive and having a different community...
A comparative analysis of structures related to
capture and processing of food, in 624 specimens belonging
to 31 species of Sebastes of Oregon was made. The
structures studied were the following: the tooth-bearing
bones (premaxillary, dentary, vomer, palatine); the
maxillary, angular, articular, parasphenoid and glossohyal
bones; the lower limb of...
The potential for Rocky Mountain mule deer (Odocoileus hemionus hemionus)
to host exotic chewing lice (Damalinia (Cervicola) sp.) believed to cause deer hair
loss syndrome in Columbian black-tailed deer (Odocoileus hemionus columbianus),
was investigated in captive deer held in pens at E.E. Wilson Wildlife Area, Corvallis,
Oregon from March 2004...
Temporal changes in gene frequencies and genotype frequencies,
monthly densities, survival rates, growth rates, trap susceptibility
and home ranges were evaluated from 291 Nuttall's cottontails
(Sylvilagus nuttallii) captured 950 times by livetrapping and 53 cottontails
collected by shooting. Electrophoretic analyses of sera revealed
protein polymorphism at the transferrin locus in...
We assessed use and selection of cover by coastal cutthroat trout (Oncorhynchus clarkii
clarkii) in six headwater streams in three watersheds in western Oregon, USA during the summer low flow period from 1 August and September 30, 2007. We tagged 1037 coastal cutthroat trout (>100 mm) with passive integrated transponder...
Comparison of the toxic effects of six herbicide formulations in simultaneous moving water and static water bioassays showed that mortality of coho salmon, Oncorhynchus kisutch (Walbaum), was less in the moving water tests. The moving water tests were conducted in troughs with powered paddlewheels while the static tests were conducted...
A study was conducted at the Pacific Cooperative Water Pollution
and Fisheries Research Laboratories, Oregon State University,
to determine the effects of pentachlorophenol (PCP) on the early developmental
stages of the steelhead trout (Salmo gairdneri). Experiments
were performed from May, 1965, through May, 1968, on the
survival, growth, and bioenergetics...
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...
The total amount of nitrogen and phosphorus in animal manures, and the proportion of this amount that becomes available as dissolved inorganic nitrogen and phosphorus within a month after manures are added to water were examined in the context of fertilization guidelines for pond aquaculture. A literature study was conducted...
Populations of organisms are influenced by both top-down (predator driven) and bottom-up (environment or resource driven) effects. Seabird research has largely focused on bottom-up factors influencing reproduction, with little emphasis on top-down. Our goal was to better understand top-down impacts on colonial nesting seabirds over a range of spatio-temporal scales....
Understanding prey quality and prey selection by predators is critical for management efforts aimed at identification and protection of essential habitats and prey. Marine predators must make daily foraging choices in a heterogenous and dynamic environment in order to meet the high energetic demands of migration, reproduction and foraging. With...
A time and energy budget was constructed for a population of
dippers (Cinclus Mexicanus) in the Cascade Range of Oregon during
winter. A total of 12,202 point observations of activity were made
from nine observation blinds from 19 November 1973 to 10 February
1974. Approximately 50 percent of all observations...
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...
The greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) is a ground nesting gallinaceous bird that requires large contiguous patches of sagebrush. Sage-grouse populations have declined, especially in the Great Basin where changes in wildfire regimes and the invasion of annual grasses have contributed to habitat loss and fragmentation. During the last...
The abundance of the 1982 brood of juvenile coho salmon
(Oncorhynchus kisutch) was determined in August 1983, and January
and April 1984 at 20 study sites spread throughout Knowles Creek,
an Oregon coastal watershed. The timing of emigration of juvenile
coho from the watershed was monitored from October 1983
through...
Dietary iodine may play an important role in the nutritional health of freshwater fish larvae. Artemia, commonly used for the culture of larval zebrafish (Danio rerio), contain low concentrations of iodine when compared with wild zooplankton. Water-soluble micronutrients, such as iodine, are difficult to deliver to Artemia due to rapid...
The movements, habitat use, and activity patterns of black-tailed deer in western Oregon, and the influence of suburban housing developments on the behavior of deer in the area, were studied and described. Radio telemetry, spotlight censusing, and a resident questionnaire were used to document the behavior of deer. Radio telemetry...
The work presented in this dissertation examines possible
modes of action for growth inhibition by anthropogenic endocrine
disrupting chemicals (EDCs) as well as endogenous hormones
associated with growth in fish. Using the sheepshead minnow (SHM)
(Cyprinodon variegatus) as a model, I developed methods to examine
perturbations in the endocrine axis...
Fire severity is hypothesized as an important driver of bird responses to wildfire. For those species that typically respond negatively to increasing severity, Accessibility of high-severity burned forest may be dependent on the proximity of unburned or low-severity burned forest to meet all of the needs of breeding bird species...
The endemic cyprinids of Lake Lanao, Philippines have been described as a species flock and are thought to be an example of explosive evolution. However, based on historical surveys, 16 of the 18 cyprinid species endemic to Lake Lanao are now believed to be extinct. Furthermore, non-native species have been...
The species compositions and densities of the littoral and pelagic zooplankton
assemblages in Crater Lake were compared. The littoral and pelagic zooplankton
assemblages of most lakes are typically different due to different habitat conditions in the
two zones. The littoral zone of Crater Lake lacks many of the habitat characteristics,...
Monitoring marine ambient sound using standardized methods supports assessments of ocean sound levels across widespread ecosystems. This thesis quantifies differences among coastal and deep-water marine soundscapes in the Atlantic and Pacific oceans. The sources of sound in a soundscape are compartmentalized into three components and compared over time and among...
Livestock grazing occurs worldwide, spanning over 25% of land globally. Effective conservation of biodiversity relies upon understanding the interactions of agricultural management practices and increasingly variable weather associated with climate change. I evaluated grazing, weather and predator-prey interactions within a grazing experiment in the sagebrush ecosystem of southeastern Oregon. I...
Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific metabolic requirements and relative energetic costs of activities, being a certain body size has both advantages and disadvantages....
Declines in populations of anadromous salmonids (Oncorhynchus spp.) in the Columbia River drainage basin have resulted in extensive programs to annually release large numbers of hatchery-raised juvenile salmonids in an effort to support salmonid restoration. The Pacific Flyway population of Caspian terns (Hydroprogne caspia) has grown from around 3,500 nesting...
The reproductive characteristics of the mountain cottontail
rabbit, Sylvilagus nuttalli (Bachman), were investigated from 269
specimens collected in central Oregon between 28 May 1968 and
28 August 1969.
Male rabbits were in breeding condition between mid-February
and 3 July 1969. Nearly 77% of the females bore four litters between
7...
Crosses were made between a stock of summer steelhead (Salmo
gairdneri) known to be resistant to infection by Ceratomyxa
shasta and stocks of summer steelhead known to be susceptible.
Ceratomyxosis, the disease caused by C. shasta was initiated by
exposure to Willamette River water. I found that the crosses
were...
Salmonid run sizes are strongly affected by their early marine stage. Fully understanding the life history of salmonids means understanding how they interact with their marine environment and with other fishes. Changes in the biological and physical environment off the Columbia River region affects the distribution and abundance of predatory...
In higher vertebrates, normal digestion and absorption by the
gastrointestinal tract are dependent on the orderly and controlled
transit of intraluminal contents. A relationship between fluid
passage through the gut and absorption from the gut has yet to be
examined in fish. In marine teleosts, the osmolality and ion concentration...
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...
Plants often encase seeds in a nutritional reward to incentivize seed dispersal by birds and mammals, but these seeds may also be removed and destroyed by seed predators. Although birds are typically thought to be the primary seed dispersers of berries in temperate systems, in southeast Alaska and other salmon-bearing...
Pacific lamprey, Entosphenus tridentatus, have shown recent and rapid declines in abundance. These anadromous fish return to streams where they mature, spawn and die. It has been inferred that Pacific lamprey enter freshwater and reside for ~ 1 year before spawning. This long exposure to the freshwater environment may affect...
Pacific lamprey is an important cultural and ecological species to freshwater ecosystems of the Pacific Northwest. Lamprey often rear in low gradient portions of watersheds that have high exposure to climate warming, yet very little is known about their thermal physiology in comparison with other anadromous fishes such as Pacific...
The Pacific Northwest has a relatively low diversity of primary freshwater fishes with most of the endemism and diversity in the Columbia River and Klamath River. However, the Oregon Coastal Subprovince defined as the coastal rivers from Miami River in the north to Sixes River in the south, has a...
The individual stocks of sockeye salmon that make up the
annual spawning migration to the Bristol Bay region of Western
Alaska are produced in the lakes and streams of ten major river
systems, which discharge into the bay over a shoreline distance of
120 miles. The hypothesis adopted in this...
Acute toxicity bioassays and growth studies, with juvenile salmon
as test animals, were used to identify and characterize the major
toxic components of a zirconium process effluent (ZPE) produced by
Teledyne Wah Chang Albany Corporation.
The major toxic component of the ZPE is ammonia. Although
other components of the ZPE...
This study was designed to provide life history information about juvenile fall Chinook salmon, Oncorhynchus tshawytscha
(Walbaum), in a small coastal river by 1) documenting the length of residence of the juveniles throughout the river, 2) exploring several factors possibly influencing their length of residence, and 3) assessing the relative...
The western United States has experienced large-scale degradation due to land use and land cover changes, invasion of annual grasses, and expansion of woody plants into grass and shrublands and the resultant altered fire regimes. These landscape-scale changes have coincided with declining mule deer (Odocoileus hemionus) populations, making habitat loss...
The fishes of Upper Klamath Lake appeared to distribute
themselves in three general groups during the summers of 1964
and 1965: (1) the chubs--unrestricted as to distribution with slight
seasonal variations; (2) rainbow trout and yellow perch -- restricted
to certain water conditions that exist only along the northern marsh...
The sperm whale (Physeter macrocephalus) shows some of the most derived characteristics of any mammal: a large body size, large brain, complex social organization and a capacity for deep foraging dives that few other marine mammals can match. Despite a history of exploitation that removed hundreds of thousands of individuals,...
The evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has been the focus of numerous research efforts. In the partially migratory...
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...
Humpback whales (Megaptera novaeangliae, Borowski 1781) in the North Pacific migrate from mid- to high- latitude summer feeding grounds along the Pacific Rim, including areas off the coasts of the U.S., Canada, Russia and eastern Asia, to tropical breeding grounds each winter along Pacific coasts of Mexico and Central America...
This thesis examined the influence of fall-spawning coho salmon on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska. During the fall of 1999 and 2000 fish rearing in ponds that received spawning salmon were...
Chinook salmon, Oncorhynchus tshawytscha, were reared from
fertilization of the eggs to several weeks after complete yolk absorption
at dissolved oxygen concentration of 3.5, 5.0, and 7.3 mg/liter and air-saturation
at temperatures of 10.5, 12.0, 13.5, and 15.0 C. Decrease of either
temperature or dissolved oxygen concentration resulted in increase...
The effects of a sublethal concentration of dieldrin (0. 2 ppb)
in the water on the growth and body composition of underyearling rainbow
and cutthroat trout held in aquaria and fed different rations of tubificid
worms or Oregon moist pellets were studied at Oak Creek Fisheries
Research Laboratory, Oregon State...
The objective of my study was to examine differences in riparian tree and shrub composition associated with adult aquatic emergence and implications for terrestrial spiders in these sites. Seasonal abundance and biomass of adult emergent aquatic insects, riparian arthropod abundances and spider densities were compared between conifer- and hardwood-dominated sites...
Co-management is considered an alternative approach to fisheries management,
however, not all co-managed fisheries have been successful. Most studies discussing the
success and failure of co-management have emphasized economic and social attributes of
success and failure, such as fishery rights and institutional arrangements. The effect on
co-management of biological characteristics,...
A fundamental objective of ecology and population biology is to identify factors that drive population dynamics and determine the population-level consequences of their interaction with the environment. Studies of reproductive performance can illuminate population dynamic processes, including the links between organismal biology, the environment, and life history theory. A central...