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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Clustering Louisiana commercial fishery participants for the allocation of government disaster payment: the case of hurricanes Katrina and Rita

Ogunyinka, Ebenezer Oluwayomi January 1900 (has links)
Master of Science / Department of Statistics / John E. Boyer Jr / The purpose of this study is to evaluate the effectiveness of the methods used for allocating disaster funds to assist commercial fishery participants as a result of Hurricanes Katrina and Rita of 2005 and to examine alternative methods to aid in determining an efficient criterion for allocating public funds for fisheries assistance. The trip ticket data managed by the Louisiana Department of Wildlife and Fisheries were used and analyzed using a cluster analysis. Results from the clustering procedures show that commercial fishermen consist of seven clusters, while wholesale/retail seafood dealers consist of six clusters. The three tiers into which commercial fishermen were originally classified can be extended to at least eleven (11) clusters, made up of three (3) clusters in tier 1 and an equal number of clusters (4) clusters in tier 2 and tier 3. Similarly, the original three tiers of wholesale/retail seafood dealers can be reclassified into at least nine (9) clusters with two clusters in tier 1, four (4) clusters in tier 2 and three (3) clusters in tier 3. As a result of the clustering reclassifications, alternative compensation plans were developed for the commercial fishermen and wholesale/retail seafood dealers. These alternative compensation plans suggest a reallocation of disaster assistance funds among individual groups of fishermen and among individual groups of dealers. We finally recommend that alternative classification methods should always be considered in order to select the most efficient criterion for allocating public funds in the future.
102

Fish and invertebrate community response to flow magnitude in the Kansas River

Gerken, Joseph Edward January 1900 (has links)
Doctor of Philosophy / Department of Biology / Craig Paukert / River discharge influences fish and invertebrate communities and understanding how hydrologic variables contribute to fish and invertebrate composition can provide information for restoration and management. This study examines the relationship between several flow regime metrics that may influence fish and invertebrate community structure in large river systems such as the Kansas River. First, I examined how hydrology influences macroinvertebrate (drifting and benthic) density and fish communities before, during, and after flooding in both main and secondary channels. I found that drifting invertebrate density increased during flooding potentially providing increased prey opportunities for fishes. I also found that fluvial dependent and generalist fish species use inundated habitats more than fluvial specialists. My results suggest that the flux of water into inundated habitats supports a unique subset of invertebrate and fish communities of the main channel. Next, I examined the importance of lateral connectivity on fish and invertebrate composition by examining differences in seasonally and permanently inundated secondary channels in relation to main channel reaches. I found that drifting and benthic invertebrate assemblages and fish assemblages differed between seasonally inundated and permanently connected secondary channels. These results suggest that maintenance of diverse secondary channel connections is useful in preserving native biota in the Kansas River. Finally, I tested if hydrologic variables influenced recruitment of four native Kansas River fishes. I found that recruitment for two of the four fish species (flathead catfish, Pylodictis olivaris, and shovelnose sturgeon, Scaphirhynchus platorynchus) increased in high flow years. These results indicate that a natural and variable flow regime may be important for maintaining fish community structure in the Kansas River. The results of this study have implications for management strategies that include the use of high flows to provide a pulse of insect prey to the main channel for fishes, restoration of natural high and low flow variability as important to fish recruitment, and diversity in secondary channel connectivity (seasonal and permanently connected) that promotes unique fish and invertebrate communities.
103

Polybrominated Diphenyl Ether (PBDE) Flame Retardants: Accumulation, Metabolism, and Disrupted Thyroid Regulation in Early and Adult Life Stages of Fish

Noyes, Pamela January 2013 (has links)
<p>Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardant chemicals that are added to plastics, electronic components, furniture foam, and textiles to reduce their combustibility. Of the three commercial mixtures historically marketed, only DecaBDE, which is constituted almost entirely (~97%) of the fully brominated congener decabromodiphenyl ether (BDE-209), continues to be used in the U.S. today. While decaBDE is scheduled for phase-out in the U.S. at the end of 2013, exposures to BDE-209 and other PBDEs will continue into the foreseeable future as products that contain them continue to be used, recycled, and discarded. In addition, decaBDE use continues to be largely unrestricted across Asia, although restricted from use in electronic equipment in Europe. </p><p>Despite limits placed on PBDE uses, they are ubiquitous contaminants detected worldwide in humans and wildlife. Major health effect concerns for PBDEs come largely from evidence in laboratory rodents demonstrating neurotoxicity, reproductive and developmental impairments, and thyroid disruption. The potential for PBDEs, particularly BDE-209, to disrupt thyroid regulation and elicit other toxic outcomes in fish is less clear. Thus, the overall objective of this thesis research was to answer questions concerning how fish, as important indicators of overall environmental health, are metabolizing PBDEs and whether and how PBDEs are disrupting thyroid hormone regulation. The central hypothesis was that PBDE metabolism in fish is mediated by iodothyronine deiodinase (dio) enzymes, which are responsible for activating and inactivating thyroid hormones, and that PBDE exposures are causing thyroid system dysfunction across fish life stages. </p><p>Under the first research aim, in vitro experiments conducted in liver tissues isolated from common carp (Cyprinus carpio) suggested a role for dio enzymes in catalyzing the reductive debromination of PBDEs. Carp liver microsomes efficiently debrominated BDE-99 to BDE-47, and enzymes catalyzing this reaction were associated predominantly with the endoplasmic reticulum (i.e., microsomal fraction) where dio enzymes are located. Competitive substrate experiments in carp liver microsomes also demonstrated that rates of BDE-99 debromination to BDE-47 were significantly inhibited upon challenges with 3,3',5'-triiodothyronine (rT3) and thyroxine (T4). This finding supported the hypothesis that enzymes involved in the metabolism of PBDEs may have high affinities for thyroid hormones. Indeed, experiments to determine apparent enzymatic kinetics (apparent Vmax and Km values) of BDE-99 hepatic metabolism suggested that enzymes responsible for the catalytic activity appeared to have a higher affinity for native thyroid hormone than BDE-99. </p><p>The second and third research aims were focused on evaluating BDE-209 accumulation, metabolism, and thyroid toxicity in juvenile and adult life stages of fish using the fathead minnow (Pimephales promelas) as a model. BDE-209 bioaccumulated and was debrominated to several reductive metabolites ranging from penta- to octaBDEs in both juvenile and adult fish exposed to BDE-209. In addition, thyroid hormone regulation in juvenile and adult male fathead minnows was severely disrupted by BDE-209 at low, environmentally relevant exposures. In juvenile minnows, the activity of dio enzymes (T4-outer ring deiodination; T4-ORD and T4-inner ring deiodination; T4-IRD) declined by ~74% upon oral doses of 9.8 ± 0.2 µg/g wet weight (ww) food at 3% body weight (bw)/day for 28 days, compared to controls. Declines in dio activity were accompanied by thyroid follicle hypertrophy indicative of over-stimulation and injury. In addition to thyroid disruption, a distinctive liver phenotype characterized by vacuolated hepatocyte nuclei was measured in ~48% of hepatocytes from treated fish that was not observed in controls. </p><p>Under the third research aim, adult male fathead minnows received dietary treatments of BDE-209 at a low dose (95.3 ± 0.41 ng/g-food at 3% bw/day) and a high dose (10.1 ± 0.10 µg/g-food at 3% bw/day) for 28 days followed by a 14-day depuration period to evaluate recovery. Compared to negative controls, adult male fish exposed orally to BDE-209 at the low dose tested for 28 days experienced a 53% and 46% decline in circulating total T4 and T3, respectively, while fish at the high BDE-209 dose tested had total T4 and T3 deficits of 59% and 62%, respectively. Depressed levels of plasma thyroid hormones were accompanied by a 45-50% decline in the rate of T4-ORD in brains of all treatments by day 14 of the exposure. The decreased T4-ORD continued in the brain at day 28 with a ~65% decline measured at both BDE-209 doses. BDE-209 exposures also caused transient, tissue-specific upregulations of relative mRNA transcripts encoding dio enzymes (dio1, dio2), thyroid hormone receptors (TR&alpha, TR&beta), and thyroid hormone transporters (MCT8, OATP1c1) in the brain and liver in patterns that varied with time and dose, possibly as a compensatory response to hypothyroidism. In addition, thyroid perturbations at the low dose tested generally were equal to those measured at the high dose tested, suggesting non-linear relationships between PBDE exposures and thyroid dysfunction in adult fish. Thus, mechanisms for BDE-209 induced disruption of thyroid regulation can be proposed in adult male minnows that involve altered patterns of thyroid hormone signaling at several important steps in their transport and activation. </p><p>A growing body of evidence describing PBDE toxicity in biota, including data generated here, along with studies showing continued and rising PBDE body burdens, raises concern for human and wildlife health. Long delays in removing PBDEs from the market, their ongoing presence in many products still in use, and their active use outside the U.S. and European Union will leave a lasting legacy of rising contamination unless more concerted regulatory and policy actions are taken to reduce future exposures and harm.</p> / Dissertation
104

On the dynamic management of marine resources

Dunn, Daniel Carl January 2014 (has links)
<p>Mismatches in the spatiotemporal variability of resource, resource users and management actions breeds inefficiency in the management of marine resources. To date, the spatiotemporal resolution and extent of fisheries management has been largely dictated by logistical and political constraints, and secondarily by the geographic range of the species or meta-population dynamics. Management units are rarely smaller than 1000 km2 in developed coastal fisheries, and management measures generally occur at resolutions larger than 100 km2. From a temporal perspective, the finest resolution of management measures is at best a month but more generally a year. As such, attempts to manage processes and patterns at sub-10 km, sub-1 month resolution often involve some level of spatiotemporal mismatch. To address the obvious spatiotemporal mismatch between a dynamic ocean and static management, to allow for a comprehensive implementation of ecosystem-based fisheries management, and to minimize inefficiency in our management of marine resources, we must seek to develop more dynamic management measures that allow managers to address scales, processes and patterns occurring under ten kilometers.</p><p>In this dissertation I apply point pattern processes, cumulative distribution functions, receiver operator characteristic curves, simulated annealing tools, regression models and clustering techniques to develop examples of two dynamic management measures and to compare the efficiency of static versus dynamic management measures. I show that autocorrelation analysis can inform the distances and times used in real-time closures based on move-on rules. Further, I identify optimum bottom temperature threshold values to separate individual species within the Northeast Multispecies Fishery from Atlantic cod. Results demonstrate that dynamic spatiotemporal management measures are widely applicable, and more effective and more efficient than static time-area closures. Unexpected trends in some results due to a changing climate indicate possible increasing thermal overlap between Atlantic cod and many other species in the fishery. Implications of scale in fisheries management and the importance of coarse scale (1 - 10km) ecological patterns to fisheries are discussed.</p> / Dissertation
105

Global sushi: A socio-ecological analysis of the Sicilian bluefin tuna fishery / Socio-ecological analysis of the Sicilian bluefin tuna fishery

Longo, Stefano B., 1969- 06 1900 (has links)
xvii, 330 p. : ill., maps. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / This dissertation is a sociological study of the Sicilian bluefin tuna fishery. It will examine the social and ecological transformation of this fishery during the modern era. This will be analyzed utilizing a sociological framework that draws on theory from environmental sociology. The Sicilian fishery has been exploited for its abundant tuna for over a millennium, providing a major source of protein for Mediterranean civilizations. However, within the last half century there has been exponential expansion of industrialized methods of production and increasing capture efforts. This has culminated in the development of bluefin tuna "ranches," which have become a highly controversial method for supplying global markets. Escalating pressure on the fishery has contributed to a host of environmental and social concerns, including pushing this important fishery to the brink of collapse. Using a combination of primary and secondary source data such as interviews with local fishers and those in the tuna ranching sector, data compiled by international agencies such as the International Commission for the Conservation of Atlantic Tunas (ICCAT) as well as archival data on the Sicilian bluefin tuna fishery, I will employ sociological methods and analyze the recent changes in social life and the environment in Sicilian fishing communities. Subsequently, this project will shed light on the globalized and industrialized nature of the modern agri-food system and lead to a better understanding of its social and environmental impacts. / Committee in charge: Richard York, Chairperson, Sociology; John Foster, Member, Sociology; Yvonne Braun, Member, Sociology; Joseph Fracchia, Outside Member, Honors College
106

Globalization and neoliberalism in Ecuador: The expansion and effects of the commercial tuna fishing industry

Bellinger, Nathan H., 1982- 03 1900 (has links)
xi, 129 p. : col. ill. / Between the 1980s and early 2000s, Ecuador's commercial tuna fishing industry evolved from an insignificant player in the global marketplace to the third largest tuna fishery in the world. The reasons behind this dramatic expansion are integrally linked to economic globalization and more specifically, the proliferation of neoliberal economic policies throughout Latin America and Ecuador. In this thesis, I link neoliberal reforms, such as increased capital mobility, free trade agreements, and export-led development, to the rapid growth of Ecuador's tuna fishery, centrally located in Manta. I then explore the place-based effects of these reforms by elucidating the social and environmental impacts of the tuna industry. I argue that while there have been some benefits, such as economic growth and job creation, expansion of Manta's tuna fishery has exacerbated local inequalities, created serious environmental problems, and led to new workplace challenges for employees in the industry. / Committee in charge: Dr. Derrick Hindery, Chairperson; Dr. Lise Nelson, Member
107

From Policy Instruments to Action Arenas: Toward Robust Fisheries and Adaptive Fishing Households in Southwest Nova Scotia

January 2014 (has links)
abstract: The coastal fishing community of Barrington, Southwest Nova Scotia (SWNS), has depended on the resilience of ocean ecosystems and resource-based economic activities for centuries. But while many coastal fisheries have developed unique ways to govern their resources, global environmental and economic change presents new challenges. In this study, I examine the multi-species fishery of Barrington. My objective was to understand what makes the fishery and its governance system robust to economic and ecological change, what makes fishing households vulnerable, and how household vulnerability and system level robustness interact. I addressed these these questions by focusing on action arenas, their contexts, interactions and outcomes. I used a combination of case comparisons, ethnography, surveys, quantitative and qualitative analysis to understand what influences action arenas in Barrington, Southwest Nova Scotia (SWNS). I found that robustness of the fishery at the system level depended on the strength of feedback between the operational level, where resource users interact with the resource, and the collective-choice level, where agents develop rules to influence fishing behavior. Weak feedback in Barrington has precipitated governance mismatches. At the household level, accounts from harvesters, buyers and experts suggested that decision-making arenas lacked procedural justice. Households preferred individual strategies to acquire access to and exploit fisheries resources. But the transferability of quota and licenses has created divisions between haves and have-nots. Those who have lost their traditional access to other species, such as cod, halibut, and haddock, have become highly dependent on lobster. Based on regressions and multi-criteria decision analysis, I found that new entrants in the lobster fishery needed to maintain high effort and catches to service their debts. But harvesters who did not enter the race for higher catches were most sensitive to low demand and low prices for lobster. This study demonstrates the importance of combining multiple methods and theoretical approaches to avoid tunnel vision in fisheries policy. / Dissertation/Thesis / Ph.D. Environmental Social Science 2014
108

Influence of Land Use and Land Cover on Aquatic Habitat in Tributaries of the Grand River, Ohio

Elsea, Troy W. January 2018 (has links)
No description available.
109

Characterizing the Link between Biological Membranes and Thermal Physiology in Antarctic Notothenioid Fishes

Biederman, Amanda M. 20 September 2019 (has links)
No description available.
110

Ecological Effects of Predator Information Mediated by Prey Behavior

Wood, Tyler C. 14 April 2020 (has links)
No description available.

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