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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.
1

Ecosystem health and environmental influences on innate immune function in the loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle

Unknown Date (has links)
Loggerhead (Caretta caretta) and green (Chelonia mydas) turtles recruit to nearshore environments as juveniles. These often degraded habitats are associated with emerging diseases such as green turtle fibropapillomatosis (GTFP), however there are few studies on immune function in sea turtles. The objective of this research was to quantify phagocytosis of the innate immune system by flow cytometry and compare levels between animals from a degraded habitat (the Indian River Lagoon, FL) to a more pristine environment (the Trident Basin, Port Canaveral, FL), and across a range of temperatures. While in vitro temperatures did not alter rates of phagocytosis, it was higher in samples obtained in the summer than winter. Rates of phagocytosis in sea turtles with GTFP and from degraded environments with increased prevalence of GTFP were low compared to animals from the more pristine environment, suggesting that the environment can alter innate immunological function and thus contribute to the development of disease. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
2

Influence of small vessel operation and propulsion system on loggerhead sea turtle injuries

Sapp, Adam 07 April 2010 (has links)
Loggerhead sea turtles (Caretta caretta) can be found worldwide, inhabiting tropical and subtropical coastal waters. The loggerhead was classified as an endangered species and placed on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List in 1996 (IUCN 2006).The problem of sea turtle mortality as a result of collisions with vessels is of increasing concern, especially in the southeastern United States, where increased development along the coasts results in increased recreational boat traffic. In the United States, the percentage of strandings that were attributed to vessel strikes has increased from approximately 10% in the 1980's to a record high of 20.5% in 2004 (NMFS 2007). This report presents results from field experiments designed to investigate the ways in which loggerhead sea turtles are injured in boat collisions, and the effectiveness of several mitigation options for reducing the risk of fatal interactions. In order to conduct these field experiments, a synthetic sea turtle carapace was designed and built that approximated the structural behavior of a biological sea turtle carapace. Hodges (2008) quantified the material strength properties of loggerhead sea turtle carapaces. From these results, it was determined that the target parameter for simulating tensile strength in a synthetic carapace should be force per unit width of sample. Hodges designed and constructed an artificial carapace made of composite material for use in controlled experiments. Modifications were made to the design proposed by Hodges (2008) to facilitate rapid construction. Several designs were tested using the force per unit width as the target strength parameter and compared to the strength of the biological carapace. Tests on the design ultimately adopted showed a force per unit width 17.6% stronger than the biological carapace. The composite material being stronger than the biological carapace means the testing will result in conservative reports of damage. Once the design and construction methods were finalized, approximately 60 artificial carapaces were fabricated for field testing. A frame, weighting scheme and buoyancy unit were designed and fabricated so that each test carapace floated at proper draft and had realistic specific gravity and weight. Field testing procedures were designed to investigate the influence of a) boat speed, b) animal position in the water column, and c) vessel propulsion system on the severity of vessel collisions on turtles. All experiments were done with small (<6 m in length) vessels. Boat/sea turtle collisions were simulated by placing a test specimen (a synthetic carapace attached to a test frame) in the water column and striking it with the vessel. The speeds considered were idle (7 km/h), sub-planing (14 km/h), and planing (40 km/hr). The two animal positions in the water column were 1) at the water surface and 2) at "prop depth" (depth to the center of the propeller hub on the standard outboard motor). Five propulsion options were tested: 1) a standard outboard motor, 2) a standard outboard motor with Hydroshield® propeller guard 3) a standard outboard motor with Prop Buddy® propeller guard, 4) a jet outboard motor and 5) a jet-propelled personal watercraft, often referred to generically as a "jet ski". The experiments typically included five trials per test configuration. Catastrophic (presumably fatal) damage was defined to occur when any damage penetrated the carapace. Small wounds (< 4 cm in length) along the sides or rear of the artificial carapace, where the shell and bone extend beyond the edge of the body cavity, were not classified as catastrophic This definition was used to classify the effectiveness of the various mitigation options. Results indicate that reducing the speed of the vessel reduces the odds of severe damage to the animals. Of all of the tests performed with the standard outboard motor (including tests with propeller guards installed), 25% of those performed at idle speed resulted in catastrophic damage, compared to 100% for planing speed tests. The two tested propeller guards both modified the type of damage to the animal when compared to similar tests with the standard motor configuration, but they only slightly reduced the risk of catastrophic damage. At idle speed, with propeller guard installed, 10% of the tests resulted in catastrophic damage. The corresponding number for the standard motor was 40%. At planing speed, 100% of the tests resulted in catastrophic damage, with or without the propeller guard. No catastrophic injuries were observed during testing of both jet propulsion systems (jet outboard and jet ski) at any speed or depth in the water column. Both feature a much smaller draft than the standard outboard, which results in little chance of striking an animal below the surface. And both the jet outboard and the jet-powered watercraft feature water intakes that are relatively smooth and appeared to slide across the animal with minimal damage to the carapace when the model animal was floating on the surface. The experiments described here involved a limited range of hull configurations; results may be different for hulls or propulsion systems drastically different than those tested here. But the results obtained indicate that equipment, in the form of the boat's propulsion system, and the mode in which it is used both play a role in defining the risk of boats to turtles in the field.
3

Cross-shelf coral reef biodiversity : does data and ecological theory fit with habitat-based species conservation models?

Radford, Benedict January 2007 (has links)
[Truncated abstract] Selection of priority areas for Marine Park conservation is often compromised by the lack of comprehensive biodiversity data and the resources and expertise necessary to gain this information directly by sampling. One cost effective alternative is the use of species groups or indicator species as surrogates for total biodiversity. However use of these surrogates requires an ecological understanding of how they reflect biodiversity gradients. A framework for unravelling these relationships has been suggested that involves relating species biodiversity to different and competing ecological models using appropriate statistical analysis. I use this framework to explore coral species biodiversity over a range of environmental gradients encompassing the North West Shelf of Australia and the Great Barrier Reef in North East Australia. ... I assessed physiological responses of corals to physical factors to corroborate crossshelf patterns in species biodiversity. Finally, I investigated to what extent coral cooccurrence based species groups (or guilds) can be used as surrogates for total coral biodiversity. The major findings of this thesis were: i) coral biodiversity along cross-shelf environments was highly correlated to specific gradients of abiotic reef conditions; ii) larval modelling indicates the potential for significant connectivity across continentalshelf environments such that differences in species distribution are not simply as a result of self seeding. iii) similar correlative patterns were demonstrated for coral species that occur along comparable abiotic gradients in reef areas of both Eastern and Western Australia, suggesting a causal relationship between the physical environment and coral biodiversity; iv) coral physiological parameters measured using lipid fractions independently corroborated the hypothesis that there is a biological basis for observed coral distributions; v) reef coral communities are not highly structured across abiotic physical gradients and biodiversity across the shelf increases as conditions become suitable for a wider range of species; vi) total coral biodiversity can be estimated very accurately (within r2 values ranging from 0.75 to 0.90) using a small number (15-30) of optimally chosen indictor species using the randomForest statistical method. These results suggest coral biodiversity over cross-shelf environments conforms most closely to the
4

Local people's perceptions of marine protected areas : a case study of Ponta do Ouro, Mozambique /

Gaspar, Anselmo Cesar. January 2008 (has links)
Thesis (M.Env.Dev.) - University of KwaZulu-Natal, Pietermaritzburg, 2008. / Full text also available online. Scroll down for electronic link.
5

Local people's perceptions of marine protected areas : a case study of Ponta do Ouro, Mozambique.

Gaspar, Anselmo Cesar. January 2008 (has links)
Marine protected areas (MPAs) cannot be managed outside the context of human societies that are dependent on their associated ecosystems and resources. This means that local people’s perceptions need to be considered in the establishment of MPAs as well as their subsequent management, planning and decision making processes. Accordingly, this study investigated respondents’ perceptions of the Ponta do Ouro – Kosi Bay MPA. The MPA is part of the now proclaimed Lubombo Trans-frontier Conservation Area (TFCA). An interviewer - administered questionnaire was used to obtain primary data from 35 respondents, all resident in the study area and who are involved in various activities based on the coastal area and its marine resources. The focus of the study was on awareness regarding the establishment, impacts of the MPA, the setting of priorities for the MPA and lastly, respondents’ roles and responsibilities The findings from the study reveal low levels of awareness of the establishment of the MPA among respondents, although there was acknowledgement of its potential contribution to biodiversity conservation. Various types of impacts of the establishment of the MPA were noted. The establishment of the MPA was perceived to negatively impact on the access to, and use of, marine resources. It was also felt that the MPA would impact on the exercise of traditional authority. Concerning the setting of future priorities for the MPA, socio-economic considerations, particularly job creation rated highest. Biodiversity conservation ranked highest in terms of factors that should shape the current priorities of the MPA. Overall, tourism and related job creation and biodiversity conservation were identified as the main opportunities associated with the establishment of the MPA. Controlling access to the area, curbing inappropriate resource use, controlling development and ensuring that local people benefit were highlighted as major opportunity benefits. Constraints were mainly considered in relation to the exercise of traditional leadership, access to the area and restrictions in selling of harvested marine resources. Regarding how to collaborate in the MPA, various skills among the respondents were mentioned, with respect to the following areas: enforcement (control, patrols and security) and community relations and awareness (including communication and the translation of documents). Lastly, while the respondents displayed both supportive and unsupportive attitudes as results of perceptions of the intended MPA, in an overall sense, the MPA was considered as a positive development. This was in spite of the perceived weak communications that exist at present between the authorities and local people. Enhanced, communication between authorities in charge of the MPA and local people could help to provide a more positive sentiment towards the MPA. This is particularly true of the local people who, if they understood the rationale for the MPA more fully and how it would impact on their use of the resources of the MPA, would be more likely to support its establishment and existence. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
6

Towards a cost-efficient & standardised monitoring protocol for subtidal reef fish in the Agulhas ecoregion of South Africa / Towards a cost-efficient & standardised monitoring protocol for sub-tidal reef fish in the Agulhas eco-region of South Africa

Bernard, Anthony Thomas Firth January 2013 (has links)
Under the growing demand for marine fish resources, and the apparent and expected impacts of global climate change, there is a need to conduct long-term monitoring (LTM) to ensure effective management of resources and conservation of biodiversity. However LTM programmes often suffer from design deficiencies and fail to achieve their objectives. These deficiencies stem from the fact that insufficient consideration is afforded to the design phase, with programmes selecting methods that are not suitable to address the objectives, or are not cost-efficient, compromising the sustainability of the LTM. To facilitate the establishment of LTM programmes along the southern coast of South Africa, background research needed to be conducted to identify which methods were most appropriate for LTM of reef fish. This study presents a detailed field-based assessment of the suitability and cost-efficiency of monitoring methods for long-term monitoring of reef fish in the Agulhas Ecoregion of South Africa. The approach adopted to identify the method, or suite of methods most suited for LTM, involved (i) the selection of methods considered suitable for LTM, (ii) the individual assessment and optimisation of method performance, and (iii) the comparative assessment of the fish community sampled by the different methods. The most suited method(s) were then identified as those that provide the most comprehensive assessment of the fish community and had the highest cost-efficiency. The research was conducted between January 2008 and 2011 in the Tsitsikamma and Table Mountain National Park (TNP and TMNP, respectively) marine protected areas (MPAs) within the Agulhas Ecoregion. The methods selected included fish traps (FT), controlled angling (CA), underwater visual census (UVC), remote underwater video (RUV), baited RUV (BRUV) and remotely operated vehicles (ROV). The individual assessment and optimisation was conducted with the FT, UVC, RUV and BRUV methods. The assessment of the FT method aimed to identify the optimal soak time, and whether or not the size of the funnel entrance to the trap affected the catch. The results identified that larger funnel entrances caught more fish and soak times of 80 minutes produced the highest catches per unit effort. However the data were highly variable and the method detected few of the species typical of the region. Fish traps were also associated with high levels of mortality of fish post-release. The assessment of UVC strip transect method involved directly comparing the precision of data collected by researchers and volunteers using a novel double-observer technique (paired-transects). The results showed considerable error in both the volunteers and researchers data, however the researchers produced significantly higher precision data, compared to the volunteers. The distinction between researchers and volunteers was not evident in the data for the dominant species of fish. For all observers, the abundance of a species in the sample had a significant influence on its detectability, with locally scarce or rare species poorly detected. UVC was able to sample the majority of species typical of reefs in the region, however it appeared plagued by observer and detectability biases. The assessments of RUV and BRUV were conducted simultaneously which enabled the assessment of the effect of bait on the observed fish community. In addition the optimal deployment time for both methods to maximise species richness and abundance was determined. The results showed that BRUV, and to a lesser degree RUV, were able to effectively survey the reef fish community for the region with a 50 minute and 35 minute deployment time, respectively. Baited remote underwater video was especially good at detecting the invertebrate and generalist carnivores, and cartilaginous species. On the other hand, RUV was more effective at surveying the microinvertebrate carnivores. Remote underwater video was characterised by higher data variability, compared to BRUV, and was ultimately considered a less cost-efficient monitoring method. Comparative methods assessments were conducted during two field experiments with the FT, UVC and BRUV methods in the TMNP MPA, and the FT, CA, UVC, RUV, BRUV and ROV methods compared in the TNP MPA. The objectives of the comparison were to investigate differences in the fish communities observed with the different methods, and to determine the power of the data to detect an annual 10% growth in the fish populations over a period of five years. The results from the method comparison were in turn used to conduct the cost-benefit analysis to determine the efficiency of the different methods at achieving monitoring objectives requiring population data from multiple trophic and functional groups with the community, and from species of fisheries importance. The results indicated that FT, CA and ROV were ineffective at monitoring the reef fish community, although CA appeared to provide valuable data for the dominant fisheries species. Both CA and FT required minimal initial investment however, the variability in the data translated into high annual monitoring costs, as the required sampling effort was great. The ROV required the highest initial investment and was identified as the least cost-efficient method. Underwater visual census was able to adequately survey the bony fish within the community, however it did not detect the cartilaginous species. Underwater visual census required a large initial investment and was not cost-efficient, as a many samples were required to account for the variability in the data. Remote underwater video provided a comprehensive assessment of the reef fish community, however it too was associated with high levels of variability in the data, compared to BRUV, reducing its cost-efficiency. BRUV provided the most comprehensive assessment of the reef fish community and was associated with the highest cost-efficiency to address the community and fisheries species monitoring objectives. During the course of this research stereo-BRUV has gained considerable support as an effective reef fish monitoring method. Although not tested during this research, stereo-BRUV is preferred to BRUV as it provides accurate data on the size of fish. However, the initial investment of stereo-BRUV is over three times that required for the BRUV. Although it is recommended that a baited video technique be used for LTM in the Agulhas Ecoregion, the choice between BRUV and stereo-BRUV will depend on the specific objectives of the programme and the available budget at the implementing agency.

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