Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"longline"”.
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Understanding and mitigating vulnerable bycatch in southern African longline and trawl fisheries
… and sharks in fishing operations, in particular longline and trawl fisheries, which have been widely held responsible for their declining population s and threatened conservation status. This thesis addresses the issue of bycatch in a holistic manner, taking into account that species, whether …
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Understanding and mitigating seabird bycatch in the South African pelagic longline fishery
… populations worldwide, with trawl, gillnet and longline fisheries considered the most destructive to seabird populations. Seabird bycatch from trawl and gillnet fisheries has been significantly reduced in recent years, but large numbers of seabirds are still killed annually by longline …
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The impact of longline fishing on the seabirds breeding on Marion Island
This study describes the impact of longline fishing on the seabirds breeding on the sub-Antarctic Prince Edward Islands. The development of a demersal longline fishery for Patagonian toothfish Dissostichus eleginoides close to the islands with almost complete observer coverage during the study …
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The bottom longline fishery and its use as a source of benthic biodiversity information around South Georgia
… chapter 2 describes and compares the two longline systems (autoline and Spanish system) used around South Georgia. It also investigates how technical changes in the gear imposed through legislation was responsible for one of the best examples worldwide of successful management on reducing …
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Sea turtle bycatch by the U.S. Atlantic pelagic longline fishery: A simulation modeling analysis of estimation methods
The U.S. pelagic longline fishery catches 98% of domestic swordfish landings but is also one of the three fisheries most affecting federally protected sea turtles (Crowder and Myers 2001, Witherington et al 2009). Bycatch by fisheries is considered the main anthropogenic threat to sea turtles (NRC …
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Spatial dynamics modeling for data-poor species using examples of longline seabird bycatch and endangered white abalone
… seabird bycatch from the U.S. Atlantic pelagic longline fishery, which focused on rare events/species for which data are generally characterized by a high percentage of zero observations. The other example was endangered white abalone off the California coast, which focused on endangered species …
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Quantification of genetic variation on Island-breeding populations of Procellariiformes : an assessment of the impact of the longline fishing industry on seabirds
The number of albatrosses that are killed on longlines in the Southern ocean is conservatively estimated to be 44 000 birds per annum. These numbers are biologically significant since albatrosses are a prime example of an extreme K-selected species. Ongoing long line fishing in the Southern ocean …
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Ecology and conservation of albatrosses and petrels at sea off Brazil
… A close association between birds and pelagic longline fishery was demonstrated through comparison of the main kernel areas used by Spectacled Petrels and the pelagic longline fleet. Stable isotopes of nitrogen (δ15N) and carbon (δ13C) in blood preserved in different ways and simultaneously …
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Bycatch and foraging ecology of sea turtles in the Eastern Pacific
… rates per species and country in trawl, longline, and gillnet fisheries, and to compile results of mitigation measures. Moreover, estimates for current annual capture rates in trawl fisheries were obtained and compared with population numbers. </p><p>This regional bycatch used all the …
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Modelling the relative impacts of trawling and longlining on Cape hake Merluccius capensis on the inshore Agulhas bank
… in catches made by commercial trawls and longlines off the South Coast (20°E). Results show that M.capensis size increases with depth and that the distribution of fish < 30 cm is mostly west of 23° E with isolated pockets east of that region. No seasonal differences were found in the …
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Aerobic and anaerobic activity metabolism of an elasmobranch
… and to define the effect of simulated commercial longline fishing capture on the swimming behavior and energy use of a shark (chapter two). The study presented in chapter one offered new insight into the energetics and behavioral partitioning of wild sharks, thereby providing a baseline from which …
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Computational imaging and automated identification for aqueous environments
… for extracting images of sh from videos of longline operations are demonstrated. A prototype digital holographic imaging device is designed and tested for quantitative in situ microscale imaging. Theory to support the device is developed, including particle noise and the effects of motion. A …
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Bycatch in the South African midwater trawl fishery for horse mackerel (Trachurus capensis) as established from observer records
… trawl, small pelagic, linefishery, shark longline and squid fisheries, yet the total catch estimates from this fishery are generally small relative to catches taken in the target fisheries.
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In Support of a Rationally Managed Fishery: Age and Growth in Patagonian Toothfish (<i>Dissostichus eleginoides</i>)
… design to sample fish caught by commercial longline, and an age estimation methodology. Because toothfish are difficult to age, I developed an ANOVA model for estimating precision and accuracy of age data relative to a standard, as the basis for a protocol for quality control of age data. …
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Movements and oceanographic associations of large pelagic fishes in the North Atlantic Ocean
… An additive modeling approach applied to longline catch-per-unit effort data further highlighted the biophysical interactions that characterize variability in swordfish catch. In the final chapter, I designed a synergistic analysis of high-resolution, 3D shark movements and satellite …
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Movements and oceanographic associations of large pelagic fishes in the North Atlantic Ocean
… An additive modeling approach applied to longline catch-per-unit effort data further highlighted the biophysical interactions that characterize variability in swordfish catch. In the final chapter, I designed a synergistic analysis of high-resolution, 3D shark movements and satellite …
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Evaluating the Conservation and Ecological Roles of Large Marine Protected Areas for Threatened Sharks
… shark bycatch and incidental mortality from longline fishing in remote ocean sectors, based on the level of fishing effort observed via satellite. Next, I explore how the space use of mobile sharks varies over their ontogeny, using a dataset of more than 300 white shark (Carcharodon …
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A comparative study of Phoebetria albatrosses' interactions with mesoscale oceanographic features south of the African continent
… vulnerable from incidental capture from high longline fisheries. These results have implications to the conservation of these albatrosses suggesting a need for a multi-faceted approach on fisheries management particularly on mitigation of seabird bycatch in the Indian Ocean Tuna Convention …
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Delination of Coastal Shark Habitat within North Carolina Waters Using Acoustic Telemetry, Fisher-Independent Surveys, and Local Ecological Knowledge
… Division of Marine Fisheries (NCDMF) gillnet and longline surveys were used to spatially delineate potential habitat for six species within Pamlico Sound. Inlet distance and temperature were among the most influential environmental factors associated with species presence, while salinity was the …
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Assessing conservation measures for five Southern African endemic shark species
… consequence of being caught as bycatch in longline fisheries, it would be difficult for this population to recover. We also attempted to classify the different areas used by spotted gully sharks in order to identified priority areas for conservation such as nursery areas. The analysis of …
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