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 22 for “"by-catch"”.
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Shark nets in KwaZulu-Natal : an evaluation of catches and alternatives
… in numbers of large sharks. The nets also take a by-catch of dolphins, sea turtles, batoids and teleosts.Catch rates of most shark species declined initially but have shown no trend since the mid-1970s. Turtle and teleost stocks do not appear to be threatened by net mortalities, but there is …
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Characterizing a Hidden Fishery: Setline Fishing in the New River, Virginia
… that are harvested from the New River, Virginia by multiple methods, yet standard creel survey approaches do not accurately sample setline effort, a popular fishing gear for catfish. I characterized the New River setline fishery by estimating setline effort and catch rates of catfish and by-catch …
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Catch, effort and socio-economic characteristics of the gill and beach-seine net fisheries in the Western Cape, South Africa
… were to provide quantitative estimates of total catch and effort, to assess the current and potential future importance of by-catch in the fisheries, to describe the socio-economic status of participants and to evaluate the management measures currently in effect.
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Environmental health risks, inequality and welfare beyond GDP
… and constrain human capital accumulation, thereby reducing the quantity of human capital per person and adversely impacting income distribution, especially among poor countries who already have low human capital. This dissertation examines two channels by which these environmentally health risks …
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Potential of a trap-fishery for the spiny lobster Palinurus delagoae off eastern South Africa : has the stock recovered?
… in 2004, and was run until 2006. Data collected by on-board scientific observers were used to explore fishing effort, catches and catch per unit effort. The recent data were compared with those for a previous experiment conducted in 1994-1997, which apparently contributed to the collapse of the …
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Aspects of the biology and population dynamics of the deep-water commercially exploited crabs off South West Africa/Namibia
… red crab Geryon maritae forms >99 percent of the catch made by traps, the balance being a by-catch of stone crab Lithodes tropicalis. Historical information dating back to the late 1970's has been examined, but most of the data analysed in this study have been collected since 1980. Most of the …
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Taxonomy, biology and management of South African sciaenid fish of the genus Umbrina
… the surf-zone to 40 m depth that is targeted by recreational shore anglers and spear fishers, whilst U canariensis occurs predominantly from 40-100m depth and is predominately landed as a by-catch in the inshore trawl fishery. Although both species occur throughout the South African eastern …
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Fish landings, discards and benthic material from demersal trawling in the western English Channel (ICES VIIe)
… and 4.4 % was invertebrates and other material (by weight). Related information about the substrate and tide were generated from British Geological Survey data and a computer simulation of the maximum mean tidal strength. In agreement with the different abiotic regime, the dominant fishes were …
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Snoek Thyrsites atun in South African waters : aspects of its biology, distribution and fishery
… in the southern Benguela region. It is exploited by both a handline and a demersal fishery. A survey of the Cape line fishery revealed that snoek line fishing effort is changing from the traditional harbour-based line-boat to the nomadic ski-boat. It was widely claimed that snoek catches are …
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Timber supply and economic impact of mountain pine beetle salvage strategies
… forest, policies have to complement AAC uplifts by strongly encouraging the salvage of mainly pine-leading stands and management options that minimize the “by-catch” of non-pine species and minimize destruction of advanced regeneration during salvage. However, this has an opportunity cost for the …
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Systematics and biodiversity of South African sea urchins
… Echinoidea (Echinodermata) were last reviewed by Clark & Courtman Stock (1976) and numerous unidentified specimens and records have accumulated since that time, plus there have been many taxonomic changes within the group. Therefore this study, which forms the first of its kind in 37 years, …
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Trophic role of small cetaceans and seals in Irish waters
… regularly occur in Irish waters was investigated by reconstructing diet using hard parts from digestive tracts and scats. Of the species examined, two (striped and Atlantic white-sided dolphin) can be considered offshore species or species inhabiting neritic waters, while five others usually …
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IUCN red listing of marine macroalgal species : a South African case study
… species are thought to be greatly affected by over-exploitation and by-catch. However, a large proportion of the oceans diversity is situated on the coastal region, particularly as benthic organisms. These environments are considered to be a high risk of disturbance and habitat alteration …
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Factors influencing cheetah (Acinonyx jubatus) distribution in Kafue National Park, Zambia
… These camera trap surveys were designed and run by the NGO Panthera Wildcat Conservation, in collaboration with Department of National Parks and Wildlife (DNPW) to estimate leopard density across the north, central, and southern regions of the park. To adapt this survey for use in cheetah …
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Optimizing Bermudagrass Management Strategies Using Aerial Imagery and Wireless Capacitive Soil Sensors
… existed between irrigation applied as measured by catch can volume and thermal mean canopy temperature (Tc) values (r = 0.40). Furthermore, the coefficient of determination between Tc and catch can volume, varied between tee (r2 = 0.19-0.41) and green (r2 = 0.54-0.68) locations, influenced by …
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From big spots to little spots: Influence of camera trap deployment on spatial capture-recapture estimates of servals (Leptailurus serval) in Ithala Game Reserve
… other mesocarnivores are frequently recorded as by-catch in camera trap surveys designed for larger carnivores which offers a unique opportunity to explore the viability of using these 'bi-catch' data for the determination of population estimates of cryptic carnivores. Spatial capture-recapture …
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The development and implementation of a joint management procedure for the South African pilchard and anchovy resources
… of the inevitability of juvenile pilchard by catch (more valued as adults for canning) in the anchovy directed fishery. The operational interactions imply a trade-off between these species, and necessitate that they are managed together. The thesis describes the development of a joint …
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Yellow Perch Production and Harvest Strategies for Semi-Permanent Wetlands in Eastern South Dakota
… was assessed in an enclosure experiment by examining growth responses. Growth rates of yellow perch and black bullheads were not decreased by the presence of the other species, indicating that interspecific competition was not occurring at the stocking densities used in my study. Instead …
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Analisi della variabilità genetica e della connettività tra popolazioni di due specie di Elasmobranchi: Raja clavata L.,1758 e Scyliorhinus canicula (L., 1758)
… and slow growth rates), they are mainly affected by anthropic influence, as fishing pressure. In fact, there is evidence that the elasmobranchs of the Mediterranean are declining in abundance, diversity and range due to the intense fishing activity. The genetic application to the fisheries plays …
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