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 71 for “"bycatch"”.
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Bycatch and foraging ecology of sea turtles in the Eastern Pacific
… anthropogenic threats. Worldwide, fisheries bycatch in on the major threats to the survival of sea turtles and that is also the case in the Eastern Pacific. To establish regional conservation priorities for the mitigation of bycatch, it is essential to first obtain a comprehensive picture of …
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Understanding and mitigating vulnerable bycatch in southern African longline and trawl fisheries
… decade there has been global concern about the bycatch of seabirds, turtles 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 …
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Understanding and mitigating seabird bycatch in the South African pelagic longline fishery
… and at sea by fishing fleets, as fisheries bycatch, as well as other human impacts. Seabird bycatch has negatively affected many seabird populations worldwide, with trawl, gillnet and longline fisheries considered the most destructive to seabird populations. Seabird bycatch from trawl and …
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Conserving dolphins and fishermen: Combining science and local knowledge to reduce cetacean bycatch
<p>Bycatch is the portion of catch that is neither targeted nor retained by fishermen. It threatens the survival of many marine mammal populations globally, and it occurs in nearly every fishing gear type. Despite its widespread occurrence, observations of bycatch are rare, and scientific data on …
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Assessment of bycatch species in the Namibia Hake directed bottom trawl fishery (1997-2014)
… management, is how to manage and mitigate bycatch caught during commercial fishing. The Namibian hake-directed bottom trawl fishery has been an important component of the Namibian fishing industry for decades. Due to the low selectivity of the bottom trawling method, bycatch has been a …
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An Assessment of Sea Turtle, Marine Mammal and Seabird Bycatch in the Wider Caribbean Region
… as a direct function of incidental capture (bycatch) in marine fisheries. Their migratory behavior exposes them to multiple fishing gear types and fishing practices and efforts to understand the rates of interaction between these taxa and fishing necessarily entails analysis of data over …
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Investigating ecosystem-level effects of gillnet bycatch in Lake Erie: implications for commercial fisheries management
… world's largest freshwater commercial fisheries. Bycatch has become a concern in current fisheries management. This study focused on four species in Lake Erie that include two major commercial and recreational species, walleye (Sander vitreus) and yellow perch (Perca flavescens); an invasive …
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Bycatch associated with a horseshoe crab (Limulus polyphemus) trawl survey: identifying species composition and distribution
… that have attempted to identify or quantify bycatch in the horseshoe crab trawl fishery. A horseshoe crab trawl survey was started in 2001 to collect data on the relative abundance, distribution, and population demographics of horseshoe crabs along the Atlantic coast of the United States. In …
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Advancing Fisheries and Aquaculture Management with Machine Learning: Bycatch Risk Prediction and Autonomous Mortality Modeling
… and aquaculture management, specifically for bycatch analysis and for predicting caged-fish mortality and productivity in offshore aquaculture. Our study found that, machine learning methods effectively assess how fishing tactics, spatial, temporal and environmental variables impact bycatch …
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Movement ecology and fisheries bycatch risk of albatross and large petrel species from Bird Island, South Georgia
… Earth, mainly because of incidental mortality (bycatch) in fisheries. Tracking these birds has improved our knowledge of how the environment and individual traits shape specific foraging and migratory strategies; however, this research is biased towards adult life-stages, which are easier to …
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Sea turtle bycatch by the U.S. Atlantic pelagic longline fishery: A simulation modeling analysis of estimation methods
… and Myers 2001, Witherington et al 2009). Bycatch by fisheries is considered the main anthropogenic threat to sea turtles (NRC 1990). Accurate and precise bycatch estimates are imperative for sea turtle conservation and appropriate fishery management. However, estimation is complicated by …
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Spatial dynamics modeling for data-poor species using examples of longline seabird bycatch and endangered white abalone
… of data-poor species. One example was 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 …
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Contextualising the bycatch 'problem' in the Olifants Estuary Small-Scale Gillnet Fishery using an Ecosystem Approach to Fisheries
… with complex conservation concerns such as bycatch. Greater considerations for broader-scale and holistic approaches, as proposed by the 'Ecosystem Approach to Fisheries' (EAF) and the 'balanced harvesting approach', are beginning to challenge some of the negative misconceptions around …
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Bycatch in the South African midwater trawl fishery for horse mackerel (Trachurus capensis) as established from observer records
… catch is taken by a single midwater trawler. The bycatch of this fishery is investigated by analysing observer records from 2004 to 2014 to report on bycatch composition, volumes and temporal and spatial patterns. Small fauna were analysed by extrapolation of sample weights and large fauna were …
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Fishery Interaction Modeling of Cetacean Bycatch in the California Drift Gillnet Fishery to Inform a Dynamic Ocean Management Tool
… is a critical aspect in efforts to reduce bycatch. In the California drift gillnet fishery static management approaches and gear changes have reduced bycatch but neither measure ascertains the underlying dynamics causing bycatch events. To avoid further potentially drastic measures such as …
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Assessing sea turtle, seabird and shark bycatch in artisanal, semi-industrial and industrial of fisheries in the Cabo Verde Archipelago
Firstly, I am very grateful to Birdlife International for the MSc scholarship. I am also very grateful to Professor Peter Ryan of the FitzPatrick Institute of African Ornithology, University of Cape Town, for agreeing to supervise this project and for his guidance, insights and comments on the …
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Patterns in the landed catches and determinants of catch composition in the South African inshore trawl fishery
… (east coast sole), has the second highest bycatch rate of all South African fisheries. For over one hundred years there has been concern about the sustainability of the harvests in this fishery. To enable effective management of the many species harvested, I aim to describe patterns in the …
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Use of demersal bycatch data to determine the distribution of soft-bottom assemblages off the West and South coasts of South Africa.
… around South Africa. Samples were collected as bycatch from demersal trawl surveys conducted along the South (one cruise) and West Coasts (two cruises).
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Analyses of Indices of Abundance for Important Groundfish Species in the Northern Gulf of Mexico from 1987-2009, Relative to Shrimp Bycatch; with Age and Growth of Three Sciaenid Species
<p>Bycatch in the shrimp fishery became of particular concern in the 1980s during the peak of shrimp harvest in the northern Gulf of Mexico. Shrimp bycatch is of major importance because the majority of catch in the fishery is not intended target species of commercial shrimp, and most of the …
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