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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.
581

Spatial Dynamics and Productivity of a Gulf of Mexico Commercial Reef Fish Fishery Following Large Scale Disturbance and Management Change

Cockrell, Marcy Lynn 18 April 2018 (has links)
The Gulf of Mexico commercial reef fish fishery has experienced significant management changes and disturbance in recent years, including transitioning two major fisheries from a traditional open access system into a limited entry individual fishing quota (IFQ) system in 2007 and 2010. Also in 2010, the Deepwater Horizon oil spill (DWH) released an estimated 4.9 million barrels of oil into the Gulf (~206 million U.S. gallons), and is still the largest U.S. environmental disaster to date. Emergency fishing closures initiated shortly after the oil spill began were successful in keeping tainted seafood from reaching markets. However, effects of DWH closures on fisher decision making, fishery productivity, and distribution of fishing effort all remain poorly understood. Understanding the range and magnitude of fishers’ responses to perturbations — including regulatory change and human-induced environmental disasters — is critical for designing effective management and disaster response policies that can meet biological, ecological, economic, social, and sustainability objectives. This work characterized the spatial and temporal patterns of productivity and fishing effort for the Gulf of Mexico (GoM) commercial reef fish fishery. Patterns of productivity and effort distribution were used to examine the response of fishers to management change and large-scale disturbance, namely the DWH fishing closures. Fisheries-dependent logbook trip reports were used to quantify revenue and catch-per-unit-effort (CPUE) patterns from 2000-2014. Novel to fisheries work in the GoM, complementary vessel monitoring systems (VMS) satellite tracking data were used to quantify high-resolution spatial distribution patterns over time, relative to the DWH fishing closures. A general linear modeling (GLM) approach was also used to examine which variables may have contributed to resilience of fishers after DWH closures. Results suggested that this fishery was largely resilient to the DWH fishing closures in 2010, although exact outcomes varied by region. Overall fleet-level productivity steadily increased over time, but regional patterns were based on major species in catch. Productivity in the western GoM was consistently highest over time, and trips in the west and central GoM were dominated by Red snapper (Lutjanus campechanus) and Vermilion snapper (Rhomboplites aurorubens). Trips in the east were dominated by Red grouper (Epinephelus morio) and Gag grouper (Mycteroperca microlepis). Shifts in spatial distribution to new productive fishing grounds or reduced competition via fewer vessels or trips may explain the increases in productivity observed over the study period. Consolidation in the fleet was apparent, with fewer individual vessels and fewer total trips over time. However, the rate of vessel drop out after DWH (5%) was far below the annual background attrition rate of ~14-20%. Relative productivity patterns inside vs. outside the boundaries of fishing closures did not change over time, and there were even some increases in productivity observed during and after DWH in the eastern GoM. Yet, vessels that dropped out after DWH were concentrated in the north-central and eastern GoM. Distribution of fishing grounds before and after DWH were highly similar, and there were increases in effort along the outer West Florida Shelf. Variability in revenue and CPUE, CPUE magnitude, and magnitude of grouper landings were significant predictors of dropping out of the fishery in the GLMs. Synergies with the Red snapper or Grouper-Tilefish IFQs may have “primed” the fishery for resilience by eliminating inconsistent or marginal fishers before the oil spill, and may further explain some of the spatially varying patterns of productivity and attrition after 2010. Resilience was likely also enhanced by the more than $2 billion in emergency compensation payments made to captains, crew, and vessel owners for lost fishing income and assistance with oil remediation efforts. This work stands to make a significant contribution to our understanding of how the DWH oil spill impacted fisheries and communities in the GoM. The results add to a growing body of literature suggesting that the acute population- and ecosystem-level impacts of the DWH oil spill were not as strong or severe as initially anticipated. This work also stands to make contributions to the broader understanding of how this fishery has performed in the wake of recent management change and major environmental disturbance.
582

Neolithic Fisheries : Osteoarchaeology of Fish Remains in the Baltic Sea Region

Olson, Carina January 2008 (has links)
<p>The variety of fish species found at the archaeological sites indicates the exploitation of local and regional ecosystems. The focus of the fisheries varies from site to site. </p><p> The study is based on the analyses of faunal materials from 10 archaeological sites from Eastern Middle Sweden, Gotland, and Åland dating to approximately 3800 – 1850 B.C. The mainland assemblages are mainly burnt and highly fragmented. When comparing burnt and unburnt bone materials, results showed a marked predominance of fish specimens within the unburnt assemblages. The burnt bone materials showed a striking preponderance of marine mammals. The burning process impairs identification and quantification of fishbone. Species presence per context complemented summary data and showed that low and medium frequency species were handled more often than summary data indicate. Intra-site studies of burnt bones demonstrated the importance of detailed studies of the taphonomic history of the faunal assemblages.</p><p> At Ajvide on the island of Gotland, large amounts of well preserved unburnt faunal remains, and ca. 600 bone fishhooks have been unearthed. Replicas of fishhooks from this assemblage were subjected to strength test, osteometric, morphological, and breakage studies. Results point to an elaborated fishing technology for capturing medium sized cod. Incremental studies of cod otoliths (ear stones) from Ajvide showed that most cod were captured in fall and winter. A comparison with the contemporaneous Jettböle site on the Åland islands, showed that in general smaller cod and herring were captured there. </p><p> The ecological conditions were somewhat different during the Neolithic. The growth pattern for cod indicate a more rapid growth for young cod but with a lower asymptotic length compared to modern cod.</p>
583

Neolithic Fisheries : Osteoarchaeology of Fish Remains in the Baltic Sea Region

Olson, Carina January 2008 (has links)
The variety of fish species found at the archaeological sites indicates the exploitation of local and regional ecosystems. The focus of the fisheries varies from site to site. The study is based on the analyses of faunal materials from 10 archaeological sites from Eastern Middle Sweden, Gotland, and Åland dating to approximately 3800 – 1850 B.C. The mainland assemblages are mainly burnt and highly fragmented. When comparing burnt and unburnt bone materials, results showed a marked predominance of fish specimens within the unburnt assemblages. The burnt bone materials showed a striking preponderance of marine mammals. The burning process impairs identification and quantification of fishbone. Species presence per context complemented summary data and showed that low and medium frequency species were handled more often than summary data indicate. Intra-site studies of burnt bones demonstrated the importance of detailed studies of the taphonomic history of the faunal assemblages. At Ajvide on the island of Gotland, large amounts of well preserved unburnt faunal remains, and ca. 600 bone fishhooks have been unearthed. Replicas of fishhooks from this assemblage were subjected to strength test, osteometric, morphological, and breakage studies. Results point to an elaborated fishing technology for capturing medium sized cod. Incremental studies of cod otoliths (ear stones) from Ajvide showed that most cod were captured in fall and winter. A comparison with the contemporaneous Jettböle site on the Åland islands, showed that in general smaller cod and herring were captured there. The ecological conditions were somewhat different during the Neolithic. The growth pattern for cod indicate a more rapid growth for young cod but with a lower asymptotic length compared to modern cod.
584

Mechanism Design For The Optimal Allocation Of Quotas And The Determination Of The Total Allowable Catch For Eu Fisheries Under An Age-structured Model

Kanik, Zafer 01 September 2012 (has links) (PDF)
In this study, we consider the mechanism design problem for the optimal allocation of fishing quotas at different total allowable catch (TAC) levels. An age-structured fish population model is employed. Fishing technologies are embedded in the economic model as a key determinant. As a result, we showed that the quota allocation mechanism is important to minimize the impact of fishing on total fish biomass or achieve maximum sustainable yield (MSY). Moreover, we indicated technology-based optimality conditions for allocation of quotas at different TAC levels, which minimize the impact of fishing on total fish biomass or enable us to achieve MSY. Under the consideration that the fishermen fulfill their remaining quotas through capturing untargeted (less revenue-generating) fish after the targeted fish population is fully caught, the fix ratio of the catch of targeted fish to untargeted fish is not valid anymore. Concordantly, we indicated technology-based optimal quota levels, including the interior solutions. In the EU, TACs are distributed among states according to the principle of &lsquo / relative stability&rsquo / which prescribes that the fishing quotas should be allocated based on historical catches of the EU states. In this context, rather than allocating the quotas based on historical catches, our main suggestion is that the structure of the fishing industry should be considered for allocation of quotas to provide the sustainability of EU fisheries and achieve responsible and effective management of the fishing industry in the EU.
585

Geochemistry and Noble Gases of Permafrost Groundwater and Ground Ice in Yukon and the Northwest Territories, Canada

Utting, Nicholas C. 11 January 2012 (has links)
In Canada’s western Arctic, perennial discharge from permafrost watersheds is the surface manifestation of active groundwater flow systems, yet understanding the mechanisms of groundwater recharge and flow in periglacial environments remains enigmatic. This thesis addresses questions on how and where groundwater recharge occurs. Watersheds were selected in Yukon (Fishing Branch River at Bear Cave Mountain) and the Northwest Territories at latitudes spanning from continuous to discontinuous permafrost (five tributary rivers to the Mackenzie River from Wrigley to Aklavik). All are characterized by perennial flow with open water in the winter, and discharge from sedimentary formations of karstic carbonates and evaporate rocks. Determinations of groundwater contributions to discharge, mixing, recharge conditions and circulation times were made on the basis of a suite of analytical approaches involving measurements of major dissolved ions, δ18O, δD, δ13CDIC, 3H, noble gases and flow gauging was conducted at some sites. The application of these tracers show that hydrogeological conditions and flow paths in permafrost terrains are surprisingly similar to those of temperate regions. Groundwater recharge was determined to be a mix of annual precipitation with contributions from snowmelt and precipitation. All systems investigated show that groundwaters have recharged through organic soils with elevated PCO2, which suggests that recharge occurs largely during summer when biological activity is high. Noble gas concentrations show that the recharge temperature was between 0 and 6 °C, which, when considered in the context of discharge temperatures, suggests that there is no significant imbalance of energy flux into the subsurface. Groundwater ages were found using the 3H-3He method and were dependent on flow path. By characterizing groundwater and surface water chemistry, the proportion of groundwater was found in numerous water courses. The possible impact of ground ice formation and melting on noble gas concentrations in groundwater was considered. To assess this link, a new method to measure the noble gas composition of ground ice bodies was developed. The method can be used to determine the origin of ice, based on changes in noble gas ratios between ice originating from compaction of snow (e.g. glacier ice) vs. ice originating from freezing of water. No significant fractionation of noble gases during groundwater freezing and ground ice formation was identified. Applied to determination of the origin of ground ice bodies, the method was shown to be both diagnostic of ice origin and un-encumbered by reactivity in the subsurface, which compromises the use of the dominant atmospheric gases (O2 and N2).   Résumé Dans l’Ouest de l'Arctique canadien, la décharge pérenne dans certaines rivières en région de pergélisol est la manifestation en surface d’une circulation d’eau souterraine; cependant la compréhension des mécanismes d’écoulement et de recharge des eaux souterraines en région de pergélisol demeure énigmatique. Cette thèse s’intéresse à la question de savoir comment et où la recharge des eaux souterraines se produit. Des bassins versants ont été choisis au Yukon (Rivière Fishing Branch à Bear Cave Mountain) et dans les Territoire du Nord-Ouest à des latitudes s’étendant du pergélisol discontinu au pergélisol continu (cinq tributaires du Mackenzie entre Wrigley et Aklavik). Toutes ces rivières ont un écoulement d’eau pérenne avec des zones non gelées et une décharge dans des formations sédimentaires de roches carbonatées et d‘évaporites. L’identification des contributions des eaux à la décharge, les mélanges, les conditions de recharge, et les temps de circulation ont été faits à partir d’analyses qui ont inclus les concentrations en éléments majeurs, leur valeur isotopique (δ18O, δD, δ13C, 3H), ainsi que leur teneur en gaz rares. A certain des sites analysés des mesures d’écoulement ont été prises. L’application de ces traceurs montre que les conditions hydrauliques et le chemin des écoulements en région de pergélisol sont similaires à ceux des régions tempérées. La recharge en eau souterraine a été identifiée comme étant un mélange de précipitations annuelles, avec des contributions de neige et de pluies. Tous les systèmes étudiés montrent que les eaux souterraines se sont rechargées en traversant des sols organiques avec une PCO2 élevée, ce qui suggère que la recharge se produire largement durant l’été quand l’activité biologique est élevée. Cependant, les concentrations en gaz nobles montre que la température de recharge des eaux souterraines était entre 0 et 6 °C ce qui indique qu’il n’y a pas de déséquilibre de flux d’énergie à l’intérieur de la zone proche de la surface. L’âge des eaux a été déterminé par la méthode 3H-3He et cet âge est dépendant du chemin d'écoulement. En caractérisant les paramètres chimiques des eaux de surface et des eaux souterraines, il a été possible de trouver la contribution des eaux souterraines aux eaux surface. Le possible impact de la formation et de la fonte de la glace souterraine sur les concentrations des gaz nobles a été considéré. Pour déterminer s’il y a un lien entre ceux-ci, une nouvelle méthode pour mesurer la concentration en gaz nobles dans les glaces souterraines a été développée. La méthode peut être utilisée pour déterminer l’origine de la glace; elle est basée sur les changements dans les rapports des gaz nobles entre la glace issue de la compaction de la neige (c’est-à-dire la glace de glacier) par opposition à la glace issue du gel de l’eau. Aucun fractionnement significatif des gaz nobles durant l’engel des eaux souterraines et la formation de glaces souterraines n’a été identifié. Appliquée à l’identification de l’origine des masses de glace enfouies, on a montré que la méthode pouvait permettre d’identifier l’origine des glaces souterraines sans qu’elle soit affectée par des réactions biologiques de sub-surface, lesquelles rendent inutilisables les gaz atmosphériques (O2, and N2).
586

Geochemistry and Noble Gases of Permafrost Groundwater and Ground Ice in Yukon and the Northwest Territories, Canada

Utting, Nicholas C. 11 January 2012 (has links)
In Canada’s western Arctic, perennial discharge from permafrost watersheds is the surface manifestation of active groundwater flow systems, yet understanding the mechanisms of groundwater recharge and flow in periglacial environments remains enigmatic. This thesis addresses questions on how and where groundwater recharge occurs. Watersheds were selected in Yukon (Fishing Branch River at Bear Cave Mountain) and the Northwest Territories at latitudes spanning from continuous to discontinuous permafrost (five tributary rivers to the Mackenzie River from Wrigley to Aklavik). All are characterized by perennial flow with open water in the winter, and discharge from sedimentary formations of karstic carbonates and evaporate rocks. Determinations of groundwater contributions to discharge, mixing, recharge conditions and circulation times were made on the basis of a suite of analytical approaches involving measurements of major dissolved ions, δ18O, δD, δ13CDIC, 3H, noble gases and flow gauging was conducted at some sites. The application of these tracers show that hydrogeological conditions and flow paths in permafrost terrains are surprisingly similar to those of temperate regions. Groundwater recharge was determined to be a mix of annual precipitation with contributions from snowmelt and precipitation. All systems investigated show that groundwaters have recharged through organic soils with elevated PCO2, which suggests that recharge occurs largely during summer when biological activity is high. Noble gas concentrations show that the recharge temperature was between 0 and 6 °C, which, when considered in the context of discharge temperatures, suggests that there is no significant imbalance of energy flux into the subsurface. Groundwater ages were found using the 3H-3He method and were dependent on flow path. By characterizing groundwater and surface water chemistry, the proportion of groundwater was found in numerous water courses. The possible impact of ground ice formation and melting on noble gas concentrations in groundwater was considered. To assess this link, a new method to measure the noble gas composition of ground ice bodies was developed. The method can be used to determine the origin of ice, based on changes in noble gas ratios between ice originating from compaction of snow (e.g. glacier ice) vs. ice originating from freezing of water. No significant fractionation of noble gases during groundwater freezing and ground ice formation was identified. Applied to determination of the origin of ground ice bodies, the method was shown to be both diagnostic of ice origin and un-encumbered by reactivity in the subsurface, which compromises the use of the dominant atmospheric gases (O2 and N2).   Résumé Dans l’Ouest de l'Arctique canadien, la décharge pérenne dans certaines rivières en région de pergélisol est la manifestation en surface d’une circulation d’eau souterraine; cependant la compréhension des mécanismes d’écoulement et de recharge des eaux souterraines en région de pergélisol demeure énigmatique. Cette thèse s’intéresse à la question de savoir comment et où la recharge des eaux souterraines se produit. Des bassins versants ont été choisis au Yukon (Rivière Fishing Branch à Bear Cave Mountain) et dans les Territoire du Nord-Ouest à des latitudes s’étendant du pergélisol discontinu au pergélisol continu (cinq tributaires du Mackenzie entre Wrigley et Aklavik). Toutes ces rivières ont un écoulement d’eau pérenne avec des zones non gelées et une décharge dans des formations sédimentaires de roches carbonatées et d‘évaporites. L’identification des contributions des eaux à la décharge, les mélanges, les conditions de recharge, et les temps de circulation ont été faits à partir d’analyses qui ont inclus les concentrations en éléments majeurs, leur valeur isotopique (δ18O, δD, δ13C, 3H), ainsi que leur teneur en gaz rares. A certain des sites analysés des mesures d’écoulement ont été prises. L’application de ces traceurs montre que les conditions hydrauliques et le chemin des écoulements en région de pergélisol sont similaires à ceux des régions tempérées. La recharge en eau souterraine a été identifiée comme étant un mélange de précipitations annuelles, avec des contributions de neige et de pluies. Tous les systèmes étudiés montrent que les eaux souterraines se sont rechargées en traversant des sols organiques avec une PCO2 élevée, ce qui suggère que la recharge se produire largement durant l’été quand l’activité biologique est élevée. Cependant, les concentrations en gaz nobles montre que la température de recharge des eaux souterraines était entre 0 et 6 °C ce qui indique qu’il n’y a pas de déséquilibre de flux d’énergie à l’intérieur de la zone proche de la surface. L’âge des eaux a été déterminé par la méthode 3H-3He et cet âge est dépendant du chemin d'écoulement. En caractérisant les paramètres chimiques des eaux de surface et des eaux souterraines, il a été possible de trouver la contribution des eaux souterraines aux eaux surface. Le possible impact de la formation et de la fonte de la glace souterraine sur les concentrations des gaz nobles a été considéré. Pour déterminer s’il y a un lien entre ceux-ci, une nouvelle méthode pour mesurer la concentration en gaz nobles dans les glaces souterraines a été développée. La méthode peut être utilisée pour déterminer l’origine de la glace; elle est basée sur les changements dans les rapports des gaz nobles entre la glace issue de la compaction de la neige (c’est-à-dire la glace de glacier) par opposition à la glace issue du gel de l’eau. Aucun fractionnement significatif des gaz nobles durant l’engel des eaux souterraines et la formation de glaces souterraines n’a été identifié. Appliquée à l’identification de l’origine des masses de glace enfouies, on a montré que la méthode pouvait permettre d’identifier l’origine des glaces souterraines sans qu’elle soit affectée par des réactions biologiques de sub-surface, lesquelles rendent inutilisables les gaz atmosphériques (O2, and N2).
587

Education units of marine fish farming

朱逸俊, Chu, Yat-chun, Jackson. January 1995 (has links)
published_or_final_version / Architecture / Master / Master of Architecture
588

Stories like a River: The Character of Indian Water Rights and Authority in the Wind River and Klamath-Trinity Basins

Dillon, John F. January 2013 (has links)
The ability to decisively benefit from ample sources of freshwater represents a pivotal challenge for American Indian nations and their self-determination in the western United States. Climate change, population growth, and capitalist pressures continue to escalate demand for water in an already dry land. This project set out to listen and add practical perspective to the importance of water as reflected in various forms of stories in the context of American Indian reserved water rights. It explores dynamic confluences and divergences of worldviews that influence American Indian nations' relationships with water in the present sociopolitical context. The integral relationship between literatures, laws, and tribal sovereignty constructs this study's theoretical framework as it broadens scholarship on this connection to include the implications of water rights. This approach leads to a critical, or perhaps "literary critical," background for examining two major water rights struggles in the western United States; the first being court decisions on the Wind River Indian Reservation, home of the Eastern Shoshone and Northern Arapaho Tribes, and secondly, the Klamath-Trinity Basin, where four federally recognized tribes recently partook in water rights settlement negotiations. Litigation and negotiations over vital water are presently limited to the minefield of ambiguous Western narratives on the values and uses of Indian water rights. While each conflict has its unique circumstances and personalities, EuroAmerican stories of control and superiority continue to justify the exploitation of water and subjugation of Indigenous human rights. Alternative forums might make room for restorying and more sustainably managing water.
589

Lummi stories from high school: an ethnohistory of the fishing wars of the 1970s

Märker, Michael 11 1900 (has links)
This study focuses on the stories and experiences of Lummi students and their teachers at Ferndale High School from 1970 to 1980. The conditions of schooling for Lummis were affected by the climate of anti-Indian hostility which was fueled by the attitudes about Native fishing rights. This conflict, referred to as the "fishing wars," culminated in the landmark 1974 Boldt Decision. Throughout the 1970s the school was a site where the cultural and political conflicts of the community were played out. This study examines the ways that Lummi students saw the school and the choices they made for survival and resistance in a complex and adverse environment. It is also a study of the teachers who were at Ferndale during the 70s and how they conducted themselves in an explosive crosscultural educational setting. Utilizing an ethnohistorical perspective, this study brings forth the stories of both Lummi students and non- Native teachers and sets them within the context of the culture-conflict climate of Whatcom County in the 1970s. This study shows how political issues were inextricably welded to cultural issues for Indian students in the 1970s.
590

The politics of the privatisation of public space :|bthe subsistence fishers of Durban, KwaZulu-Natal.

Dray, Amanda. January 2009 (has links)
In today’s globalised world, countries including South Africa, are pursuing neoliberal economic policies which have many negative effects on ordinary citizens. One such effect is the privatisation of public space which is an important resource for all citizens. This thesis sets out to examine the privatisation of public space along the Durban coast and the subsequent loss of fishing sites for local subsistence fishers. The thesis draws on literature that is critical of contemporary processes of neoliberal governance. The research approach is a qualitative approach where data collection is predominantly through oral evidence. In-depth interviews were conducted with fishers and other stakeholders. Participatory observation was also used to gather data through the attendance of meetings, protests and workshops that pertain to the fishers. The thesis shows how these fishers are being excluded from using public resources along the coast and thereby prevented from making a living. Most of the spaces that have been privatised are being transformed into upmarket developments or used to further trade through the expansion of the Durban Harbour. In addition, the thesis reveals that the fishers are losing a way of life, and experiencing a loss of identity and a communal subsistence economy. The fishers have become ‘invisible’ to the state, and to the authorities. Current marine legislation does not recognise this group of fishers as subsistence fishers. In response, the fishers have established the KwaZulu-Natal Subsistence Fishermen’s Forum in order to mobilise against the broader processes of exclusion and marginalisation resulting from neoliberal pro-growth development policies. Their strategies include protest, deliberation with the state, and striking alliances with other social movements in a broader process of anti-globalisation struggle. / Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2009.

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