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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.
121

Measuring the recovery of the Benguela Current Large Marine Ecosystem: an application of the DPSIR framework

Mukuvari, Itai 30 April 2015 (has links)
Overfishing in the Benguela Current Large Marine Ecosystem (BCLME) resulted in degradation of the ecosystem. This study used the Driver-Pressure-State-Impact-Response (DPSIR) indicator framework to determine whether the ecosystem is now recovering. Indicator trends were analysed using various data sources that included government institutions and intergovernmental institutions. The results showed that the overall effect of Driver indicators was negative. This was mainly because of socio-economic pressure such as the need to create more jobs in light of rising national unemployment and the declining contribution of the fisheries sector to Gross Domestic Product (GDP). In addition to scientific advice, socio-economic factors also influenced the determination of Total Allowable Catches (TACs). The overall trend of Pressure indicators was positively influenced by the effect of TACs. The TACs reduced the quotas allocated for commercial fishing. Environmental factors did not seem to play a significant role in this study. State indicators had mixed results with the indicators assessed almost split in the middle between those showing a positive trend and those showing a negative trend. On the other hand, Impact and Response indicators showed overall positive results. Therefore, the conclusion of the study was that the degradation of the BCLME has slowed down and there are some signs of recovery. / Environmental Sciences / M.Sc. (Environmental Science)
122

The status of scleractinian corals in Hong Kong and theirconservation

Wan, Manna., 溫雯娜. January 2001 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
123

Environmental siting suitability analysis for commercial scale ocean renewable energy: a southeast Florida case study

Unknown Date (has links)
This thesis aims to facilitate the siting and implementation of Florida Atlantic University Southeast National Marine Renewable Energy Center (FAU SNMREC) ocean current energy (OCE) projects offshore southeastern Florida through the analysis of benthic anchoring conditions. Specifically, a suitability analysis considering all presently available biologic and geologic datasets within the legal framework of OCE policy and regulation was done. OCE related literature sources were consulted to assign suitability levels to each dataset, ArcGIS interpolations generated seafloor substrate maps, and existing submarine cable pathways were considered for OCE power cables. The finalized suitability map highlights the eastern study area as most suitable for OCE siting due to its abundance of sand/sediment substrate, existing underwater cable route access, and minimal biologic presence. Higher resolution datasets are necessary to locate specific OCE development locales, better understand their benthic conditions, and minimize potentially negative OCE environmental impacts. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
124

Effects of no-take marine reserves on fish assemblages in Brazil : an assessment using stereo-videos /

Rolim, Fernanda Andreoli. January 2019 (has links)
Orientador: Otto Bismarck Fazzano Gadig / Abstract: The establishment of no-take marine reserves (NTRs), i.e. areas with total fishing restrictions, has been an alternative worldwide aiming to preserve both biodiversity and ecosystem functions. Brazil has important NTRs with few studies describing their relevance and efficiency for marine life. With this, the central objective of this thesis was to evaluate the effects of NTRs on fish assemblage, testing the hypothesis that the differences in richness, abundance, biomass and fish body size is more explained by protection status than environmental characteristics. Thus, innovative techniques in Brazil, Baited Remote Underwater stereo-Videos (stereo-BRUVs) and Diver Operated stereo-Videos (stereo-DOVs) were tested in the Southwestern Atlantic, comparing with traditional visual census (stationary point count and belt transects), and used to analyze the effects of the Tupinambás Ecological Station and Abrolhos Marine National Park on fish assemblages. For this, fish assemblage characteristics, such as richness, abundance, biomass and body size, were compared to areas where fishing is allowed, and the habitat complexity was estimated through the footages. Concerning methods comparison, stereo-DOV showed to be more effective, sampling more richness and abundance within less effort, and Stereo-BRUVs showed to sample a very specific assemblage, comprised mostly by mobile and large bodied fish species, usually targeted by fisheries. Within both NTRs evaluated, target species characteri... (Complete abstract click electronic access below) / Resumo: O estabelecimento de reservas marinhas de restrição total (No-take reserves - NTRs), ou seja, áreas com proibição total de pesca, tem sido uma alternativa mundial para preservar a biodiversidade e as funções dos ecossistemas. O Brasil tem importantes NTRs com poucos estudos descrevendo sua relevância e eficiência para a vida marinha. Com isso, o objetivo central desta tese foi avaliar os efeitos de NTRs em assembleias de peixes, testando a hipótese de que as diferenças em riqueza, abundância, biomassa e tamanho corporal dos peixes são mais explicadas pelo status de proteção do que por características ambientais. Para tanto, técnicas inovadoras no Brasil, estéreo-vídeos subaquáticos com isca (Baited Remote Underwater stereo-Videos - stereo-BRUVs) e estéreo-vídeos operados por mergulhador (Diver Operated stereo-Videos - stereo-DOVs) foram testados no Atlântico Sudoeste, comparando com os censos visuais tradicionalmente aplicados (estacionário e transecto), e utilizados para analisar os efeitos da Estação Ecológica Tupinambás e do Parque Nacional Marinho dos Abrolhos nas assembleias de peixes. Para isso, as características das assembleias de peixes em termos de riqueza, biomassa, abundância e tamanho corpóreo, foram comparadas com as áreas onde a pesca é permitida, e a complexidade do habitat foi estimada através das imagens. Em relação à comparação dos métodos, o estéreo-DOV apresentou maior eficiência, amostrando mais riqueza e abundância com menor esforço, e o estéreo-BRUV am... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor
125

Small, no-take marine protected areas and wave exposure affect temperate, subtidal reef communities at Marmion Marine Park, Western Australia

Ryan, Kylie A. January 2008 (has links)
[Truncated abstract] The ecological effects of marine protected areas (MPAs) in temperate ecosystems are poorly understood relative to their tropical counterparts. The limited number of rigorous empirical studies supporting existing theoretical models, increasing public awareness of the importance of marine conservation strategies and legislative requirements to review management effectiveness provide further impetus to study temperate MPAs. Investigations should consider confounding effects of natural variability if MPA effects are to be clearly demonstrated. This research helps to address these needs by investigating the short term effects of sanctuary zones (no-take MPAs where fishing is prohibited) and wave exposure at Marmion Marine Park, Western Australia. The three sanctuary zones at Marmion Marine Park are extremely small (0.061 0.279 km2) compared to most reported in the literature. The sanctuary zones are nested within a larger, fished zone (94.95 km2). The sanctuary zones have been protected from fishing since the year 2000. A post-hoc, asymmetrical sampling design was used in this study and involved surveys of fishes, mobile invertebrates and macroalgae at one sanctuary zone and two fished sites (controls) at each of three successive, subtidal reef lines. The three reef lines are exposed to a gradient in wave energy. The size structure and abundance of the heavily exploited Panulirus cygnus (Western Rock Lobster) were positively affected by protection from fishing in sanctuary zones, despite the highly mobile nature of this migratory species. The mean abundance of legal size lobsters was higher in sanctuary zones compared to fished sites during an interannual study (2003, 2005 and 2006). The total abundance of lobsters and the mean abundance of legal size lobsters were higher at inshore and offshore sanctuary zones compared to fished control sites during a 2005/2006 fishing season study. These zoning effects did not vary with the time of survey. ... Furthermore, the abundance of large lobsters in sanctuary zones decreased with the duration of the 2005/2006 fishing season. Similarly, it is likely that sanctuary zones are too small relative to the movement of fishes to adequately protect stocks of some targeted species. The small sanctuary zones at Marmion are unlikely to offer protection to highly mobile species over the long term. And finally, ecological assemblages within each level of wave exposure are distinct. Consequently for each assemblage type, the current reserve design does not include replication of sanctuary zones and does not offer any 'insurance' in the event of isolated impacts affecting a particular zone. This study has identified the benefits and deficiencies of the design and function of small no-take temperate MPAs in Western Australia. An increase in the size and number of sanctuary zones within each wave exposure level will help to address the v shortfalls of the zoning scheme and enhance the conservation benefits of management at Marmion Marine Park. More generally, this study demonstrates that the mobility of the species to be protected from fishing should be considered when designing MPAs. Lessons learned from this work will be beneficial for the future management and conservation of resources in the region and elsewhere.
126

Designing effective protected area networks - integration of the tropical cyclone disturbance regime in the Great Barrier Reef Representative Area Program a GIS application /

Debort, Sophie. January 2006 (has links)
Thesis (M.Sc.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: p. 87-93.
127

Assessment of the effect of Goukamma Marine Protected Area on community structure and fishery dynamics /

Götz, Albrecht. January 2005 (has links)
Thesis (Ph. D. (Ichthyology and Fisheries Science))--Rhodes University, 2006.
128

El Periodo Precerámico en el valle de Chao

Cárdenas, Mercedes 10 April 2018 (has links)
The Preceramic Period in Chao Valley The author presents the evidence recovered from Preceramic Period sites discovered during the Survey Project at Chao Valley, with special emphasis on those situated on the dry Las Salinas pampa in order to compare these with others located in other parts of the valley. / Se presentan los datos relacionados con sitios del Periodo Precerámico descubiertos cuando se realizó el inventario y catastro de Chao, con especial énfasis en aquellos situados en la pampa árida de Las Salinas para contrastarlos con los otros existentes en los varios sectores del valle.
129

Empirical studies of fish movement behaviour and their application in spatially explicit models for marine conservation

Kerwath, Sven Ebo January 2006 (has links)
This thesis investigates the movement behaviour of South African two coastal fish species and evaluates the effectiveness of marine protected areas (MPAs) in their protection and management. Its primary focus is on resolving the movement patterns of roman Chrysoblephus laticeps (Sparidae) in and around the Goukamma and Castle Rock MPAs in the Western Cape province of South Africa. A pilot study of the methodology investigated the movement behaviour of spotted grunter Pomadasys commersonnii (Haemulidae) in the sheltered East Kleinmonde Estuary in the Eastern Cape province. The application of different tagging methods was tested in a controlled tank experiment. Tagged roman were monitored over a 198-day period. Barbed dart, t-bar anchor and Visible Implanted Fluorescent Elastomer (VIFE) tags were compared. Application techniques and underwater visibility of VIFE tags were tested on roman and on fransmadam Boobsoidia inornata in a pilot study. Needles of gauge 25 were found to be optimal for VIFE tag application. Whereas VIFE tagging caused fin rot in fransmadam, it had no negative effect on roman. VIFE tagged fish could be identified by divers from a distance of three metres under ambient light in an observation tank in five metres water depth. There was no significant difference in growth rate between groups of roman with different tags and controls after 198 days. High tag loss rates were experienced for barbed dart and t-bar anchor tags, although barbed dart tags performed better than t-bar anchor tags. Although some of the VIFE marks had deteriorated, all VIFE tagged fish were individually recognised at the end of the study. Conventional dart and VIFE tags are feasible methods to tag roman. However, the high tag loss rate of conventional tags must be taken into account in the design of a tagging study. Previous mark and recapture studies on roman are beset with a number of problems. Poor experimental design and low precision of capture positions resulted in equivocal results of limited value. A tagging experiment was designed to eliminate ambiguity in data interpretation and to produce a dataset that could be used to model roman residency and dispersal. A combination of conventional barbed dart tags and Visible Implanted Fluorescent Elastomer tags was used to tag roman in the Goukamma Marine Protected Area (GMPA) on the temperate South African south coast. Sixty one percent of roman were recaptured within 50 m of the tagging position. A small proportion moved considerable distances of up to four kilometres. The extent of these movements was not dependent on fish size or sex. Data from this experiment and from a previous tagging study in the Tsitsikamma National Park (TNP) were used to model the resident behaviour of roman. The model suggests a probability of 91% (GMPA) and 94% (TNP) of residency within a 10000 m² cell. This result suggests that individual roman will benefit from protection in small MPAs. A different experimental approach was required to investigate the exact home range of this species. Firstly the feasibility of using acoustic telemetry to study the movement of coastal fish in South Africa was investigated. The telemetry equipment comprised two VEMCO V8 transmitters and a VEMCO VR60 receiver linked to a directional hydrophone. A tank experiment was conducted to examine the effects of the transmitter implantation. A tracking experiment was conducted on spotted grunter Pomadasys commersonnii in the East Kleinmonde Estuary. Operated fish recovered quickly and, with respect to swimming behaviour and growth rates, no differences were found between fish with implants and controls. The maximum detection range in the estuary was 400 m. Interference between different transmitter frequencies was negligible. Transmitter location recordings were found to be accurate within five metres. Two fish were tracked over a seven-day period. The fish preferred the lower reaches of the estuary where they made repeated and prolonged use of specific areas. The success of the initial experiments allowed this method to be used to investigate the spatial utilisation and activity patterns of roman Chrysoblephus laticeps. Surgically implanted VEMCO V8, V13 and V16 transmitters were used to track 13 roman inside the Castle Rock MPA in False Bay. Transmitters implanted into C. laticeps in tanks had no apparent effects on growth and physiology. Manual boatand diver-based tracking experiments covered a 17-month period. A VEMCO VRAP radio acoustic positioning system was used over two one-month periods during and after the spawning season of roman. Analysis of data using a 95% fixed kernel algorithm suggests that roman are resident throughout their adult life, occupying home ranges between 1000 and 3000 m². Activity was lower at night. During periods of cold-water upwelling, fish retreated into caves. During the spawning season, females extended their home ranges, possibly to mate with different males. These results confirm that this species is well suited for protection and management with small MPAs. The effect of two MPAs on the South African south coast on the population of C. laticeps was simulated with a spatially explicit individual based model (IBM). Life history parameters determined in recent studies and the effect of fishing on the size of sex change was taken into account. Fish densities and size frequencies were based on recent underwater visual census. The distribution of suitable habitat in the study areas was also incorporated. The results show a rapid recovery of the fish size frequency spectrum and sex ratio to pre-exploitation levels inside both MPAs. Little 'spillover' of fish into the fished areas occurred resulting in negligible improvement of catches. The results suggest that for resident species like roman, even small MPAs offer sufficient protection.
130

Fish From Afar Marine Resource Use At Caracol, Belize

Cunningham, Smith Petra 01 January 2011 (has links)
The ancient Maya had strong ties to the sea. The trade, transportation and use of marine resources were important not only to coastal Maya communities, but also to the heavily populated cities that lay many miles inland. A review of zooarchaeological evidence recovered from excavations at the inland site of Caracol, Belize suggests that the inhabitants imported marine fish for food, marine shell for working into trade items, and sharks teeth and stingray spines for ritual use. This thesis examines the manner in which fish and other marine resources were used, procured and transported from the coast to the site of Caracol. The possibility that certain marine fish might have been transported alive to the site is explored. An examination of present day fishing and animal husbandry practices suggests that many species could have survived an inland trip in ancient times if transported under conditions that allowed for water exchanges and minimized stress. Marine resources had important economic and ritual significance to the people of Caracol. Understanding the methods by which these valuable items were transported and traded ultimately facilitates a greater understanding of the economic and socio-political relationships among these ancient polities.

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