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Theses/Dissertations

Portland State University

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Articles 1 - 11 of 11

Full-Text Articles in Aquaculture and Fisheries

Understanding The Importance Of Intermittently Fragmented Stream Habitat For Isolated Westslope Cutthroat Trout (Oncorhynchus Clarki Lewisi) In The Colville National Forest, Washington, Forrest Michael Carpenter Dec 2016

Understanding The Importance Of Intermittently Fragmented Stream Habitat For Isolated Westslope Cutthroat Trout (Oncorhynchus Clarki Lewisi) In The Colville National Forest, Washington, Forrest Michael Carpenter

Dissertations and Theses

Climate change and anthropogenic effects have vastly reduced Westslope Cutthroat Trout (Oncorhynchus clarki lewisi, WCT) habitat throughout their range, including the Colville National Forest in northeastern Washington where this study was conducted. Many native salmonid populations have declined in abundance since the early 1900s due to a variety of climate- and human-driven forces. Westslope Cutthroat Trout are especially sensitive to habitat loss or degradation and to climate change. Together, climate change, habitat degradation, and non-native salmonid invasions are contributing to increasingly fragmented WCT populations. Ongoing and predicted future warming trends are expected to further fragment these populations and isolate them ...


A Landscape Approach To Determining And Predicting Juvenile Coho Salmon (Oncorhynchus Kisutch) Movement Timing And Growth Patterns Prior To Ocean Entry, Amelia Lee Johnson Aug 2016

A Landscape Approach To Determining And Predicting Juvenile Coho Salmon (Oncorhynchus Kisutch) Movement Timing And Growth Patterns Prior To Ocean Entry, Amelia Lee Johnson

Dissertations and Theses

Coho salmon (Oncorhynchus kisutch) rely on unique habitats during the winter season, which may dictate how much individuals may grow and when migration from freshwater rearing habitat to the ocean occurs. Here I analyze movement timing and growth patterns for coho salmon through a field-based study and a literature review. For the field portion, I examined hatchery-stocked juvenile coho salmon across four stream basins in the Russian River watershed, California to determine the relative importance of climate, landscape, and fish size metrics in predicting movement and growth patterns over a winter rearing and spring smolt outmigration time period (December 2014-June ...


Cascades Island Lamprey Passage Structure: Evaluating Passage And Migration Following Structure Modifications, Siena Marie Lopez-Johnston Dec 2014

Cascades Island Lamprey Passage Structure: Evaluating Passage And Migration Following Structure Modifications, Siena Marie Lopez-Johnston

Dissertations and Theses

Pacific lamprey (Entosphenus tridentatus), an endemic species to the Columbia River Basin, U.S.A, has experienced staggering decreases in returns to spawning territories in recent decades. As lamprey are threatened severely by a lack of passage at mainstem dams, lamprey specific passage structures have been designed and constructed to address the problem. The Cascades Island Lamprey Passage Structure (LPS) at Bonneville Dam is the longest and steepest structure of its type, following the addition of an exit pipe which allows lampreys to travel from the tailrace of the dam to the forebay. The intent of this study was to ...


Gene Expression Life History Markers In A Hatchery And A Wild Population Of Young-Of-The-Year Oncorhynchus Mykiss, Ian D. F. Garrett Sep 2013

Gene Expression Life History Markers In A Hatchery And A Wild Population Of Young-Of-The-Year Oncorhynchus Mykiss, Ian D. F. Garrett

Dissertations and Theses

Life history within a single species can vary significantly. Many of these differences are associated with varying environmental conditions. Understanding what environmental conditions cue alternate life histories within a single species has been researched extensively. In salmonid fishes, more than almost any other group, varying environmental conditions give rise to individuals within species that take markedly different life history trajectories.

Oncorhynchus mykissis a species of salmonid native to the Pacific Northwest region of North America. This species has two life history forms, anadromous and resident. The anadromous form spends a portion of its life in ocean while the resident life ...


Ccaat/Enhancer-Binding Protein Delta (C/Ebp-Delta) Expression In Antarctic Fishes: Implications For Cell Cycle And Apoptosis, Isaac Martin Sleadd Aug 2013

Ccaat/Enhancer-Binding Protein Delta (C/Ebp-Delta) Expression In Antarctic Fishes: Implications For Cell Cycle And Apoptosis, Isaac Martin Sleadd

Dissertations and Theses

Chapter 1: Antarctic fishes are extremely cold adapted. Despite their inability to upregulate heat shock proteins, recent studies have demonstrated a capacity for heat response in these animals. A cDNA microarray study looked at the Notothenioid fish Trematomus bernacchii and revealed heat sensitivities for hundreds of genes, two of which code for members of the CCAAT/Enhancer-binding protein (C/EBP) family of transcription factors. These molecular switches are best known for their roles in apoptosis, inflammation and cell cycle arrest. This dissertation further elucidates the role of C/EBP-delta in the Antarctic fishes T. bernacchii and Pagothenia borchgrevinki.

Chapter 2 ...


Evaluating The Effects Of Road Crossing Structures On Stream-Associated Amphibians In The Wilson River Watershed, Tillamook State Forest, Oregon, Sara Erin Twitchell Mar 2013

Evaluating The Effects Of Road Crossing Structures On Stream-Associated Amphibians In The Wilson River Watershed, Tillamook State Forest, Oregon, Sara Erin Twitchell

Dissertations and Theses

As replacement and removal of undersized culverts gains momentum as an effective technique for restoring natural stream flows and removing fish passage barriers, it is important to evaluate the benefits of these efforts on the in-stream and adjacent riparian habitat for other species of potential concern. This study compares stream-associated amphibian (SAA) occurrence in streams adjacent to different road crossing structures on unpaved forest roads in the Wilson River watershed located within the Tillamook State Forest, Oregon. Surveys were conducted at road crossing structures for three taxa of SAA; Pacific giant salamander (Dicamptodon tenebrosus), coastal tailed frog (Ascaphus truei), and ...


The Effects Of Hypoxia And Temperature On Developing Embryos Of The Annual Killifish Austrofundulus Limnaeus, Skye N. Anderson Jan 2012

The Effects Of Hypoxia And Temperature On Developing Embryos Of The Annual Killifish Austrofundulus Limnaeus, Skye N. Anderson

Dissertations and Theses

Little is known about the physiology or biochemistry of hypoxia (reduced levels of oxygen) tolerance during development in vertebrate embryos. In most species, relatively brief bouts of severe hypoxia are lethal or teratogenic. An exception to such hypoxia intolerance is the annual killifish Austrofundulus limnaeus, in which populations persist in hypoxic environments. This species inhabits seasonal ponds in Venezuela, surviving through the dry season in the form of diapausing embryos. Embedded in the pond sediment, embryos of A. limnaeus are routinely exposed to hypoxia and anoxia (lack of oxygen) as part of their normal development. Here, we exposed embryos to ...


Metabolic Support Of Anaerobiosis In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Andrew Mccracken Jan 2012

Metabolic Support Of Anaerobiosis In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Andrew Mccracken

Dissertations and Theses

Embryos of the annual killifish Austrofundulus limnaeus display a remarkable tolerance to anoxia during development, most notably during embryonic diapause. Little is known about the metabolic or enzymatic changes that accompany this state of anoxia tolerance. This study examined the metabolic changes associated with exposure to anoxia by measuring the activity of the enzyme phosphoenolpyruvate carboxykinase (PEPCK), and by profiling the concentration of 31 metabolites ranging from amino acids to citric cycle intermediates at 4 different developmental stages, diapause 2 (DII), 4 days post diapause (dpd), 12 and 22 dpd. Embryos of A. limnaeus showed stage specific changes in concentrations ...


Relative Heart Ventricle Mass And Cardiac Performance In Amphibians, Gregory Joseph Kluthe Jan 2012

Relative Heart Ventricle Mass And Cardiac Performance In Amphibians, Gregory Joseph Kluthe

Dissertations and Theses

This study used an in situ heart preparation to analyze the power and work of spontaneously beating hearts of four anurans (R. marina, L. catesbeianus, X. laevis, P. edulis) and three urodeles (N. maculosus, A. tigrinum, A. tridactylum) in order to elucidate the meaning of relative ventricle mass (RVM) in terms of specific cardiac performance variables. This study also tests two hypotheses: 1) the ventricles of terrestrial species (R. marina, P. edulis, A. tigrinum) of amphibians are capable of greater maximum power outputs (Pmax) compared to aquatic species (X. laevis, A. tridactylum, N. maculosus, L. catesbeianus) and, 2) the ...


Policy Analysis For Optimizing Native Fisheries On The Mckenzie River, Mary Ray May 2001

Policy Analysis For Optimizing Native Fisheries On The Mckenzie River, Mary Ray

Master of Environmental Management Project Reports

The impact of hatchery fish on native populations has been extensively studies, especially as environmental management has generally moved toward a conservation focus. In Oregon, the McKenzie River native rainbow trout population has been the focus of recent interest groups attempting to induce a change in management practices to support native fisheries. The McKenzie River Chapter of Trout Unlimited is interested in learning more about the impacts that hatchery stocked rainbow trout have on native river populations. It is the group's intent to seek a rule change to management by the Oregon Department of Fish and Wildlife. A review ...


The Chromosome Constitutions Of A Hybrid Salmonid And Its Parental Types: Salmo Gairdneri And Salmo Clarki, Peter Bruce Jacky May 1976

The Chromosome Constitutions Of A Hybrid Salmonid And Its Parental Types: Salmo Gairdneri And Salmo Clarki, Peter Bruce Jacky

Dissertations and Theses

A study was undertaken to investigate the application of tissue culture and histochemical banding techniques normally used in mammalian studies to fish cells and to examine the mechanisms of chromosome evolution and speciation in salmonids by comparing the chromosomes of the hybrid to those of the parental types. The application of banding techniques was generally unsuccessful in revealing bands, though quinacrine staining did reveal the presence of two fluorescent spots in the vicinity of the centromere. These were thought to be heterochromatic blocks, possibly related to the high incidence of centric fusion or fission in salmonids. Results of chromosome analysis ...