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1
Goshe, Lisa R. "Age at maturation and growth rates of green sea turtles (Chelonia Mydas) along the southeastern U.S. Atlantic Coast estimated using skeletochronology." View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-1/goshel/lisagoshe.pdf.
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Le, Gouvello Du Timat Diane Zelica Marie. "The effects of turtle-introduced nutrients on beach ecosystems." Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/6959.
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Resource subsidies are flows of nutrients from one ecosystem to another. Sandy beach ecosystems are at the interface between land and sea and thus receive nutrients from both land/seascapes. The seasonal nesting of sea turtles introduces large inputs of eggs, and so nutrients, onto sandy beach ecosystems, but little is known about the effects of these spatially and temporally variable nutrient input pulses on the dynamics of consumers in the recipient system. In this study, I examined the ecological role of sea turtles as vectors of nutrients that introduce large amounts of nutrients (in the form of eggs) from distant foraging grounds into nutrient-poor beach ecosystems. Although some of the nutrients return to the sea in the form of hatchlings, nutrients from unhatched and depredated eggs, dead and predated hatchlings, as well as chorioallantoic fluid and egg shells remain on the beach and presumably enter sandy beach food webs. I hypothesized that turtle nutrients significantly increase the availability of nutrients to sandy beach ecosystems and that those nutrients are incorporated by both terrestrial and marine food webs. These hypotheses were tested by comparing isotopic signatures of 13C and 15N of consumers on beaches with high and low turtle nest densities. The response of meiofauna to the decomposition of turtle eggs was also investigated. I predicted that meiofaunal abundance is positively affected by turtle nutrients and that higher meiofaunal abundances will be obtained in decomposing, depredated nests. I tested this hypothesis by comparing meiofaunal abundance in naturally predated nests to densities away from turtle nests (as a control). An in situ experiment that mimics conditions of naturally predated sea turtle nest, was set up to test meiofaunal community responses to turtle nutrients over time. The study indicates that sea turtle eggs represent a short pulsed resource subsidy that increases the nutrient and energy budget of sandy beach ecosystems. The results show that of the five potential nutrient pathways tested, ghost crabs appear to consume egg nutrients in measurable quantities, altering their diet and feeding behaviour according to food availability. The study also showed that there was a strong, but short-lived positive response of meiofauna to the introduction of nutrients, with increased abundance of all taxa in predated nests and experimental treatments. This response was particularly strong for nematodes which peaked in abundance after seven days. I conclude that turtle-derived nutrients represent a pulsed resource subsidy that makes significant contribution to the energy budget of sandy beach/dune ecosystems.
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Hamann, Mark. "Reproductive cycles, interrenal gland function and lipid mobilisation in the green sea turtle Chelonia mydas /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16903.pdf.
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Weber, Sam. "Maternal effects in the green turtle (Chelonia mydas)." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/119965.
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In oviparous animals, maternal traits such as the investment of resources in eggs and oviposition site selection are often important determinants of offspring phenotypic quality, and may have an adaptive role in tailoring offspring phenotypes to local environmental conditions. This thesis examines the adaptive significance of two specific maternal traits in the green turtle (Chelonia mydas); namely the deposition of fat-soluble antioxidants in egg yolk, and the selection of nest sites via natal homing. (Please view 'front matter' file for full abstract)
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Whitman, Elizabeth Rose. "Factors Affecting Green Turtle Foraging Ecology Across Multiple Spatial Scales." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3870.
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The hierarchical levels at which resource selection occurs can have important consequences for individual and population energy budgets and structure the impacts of a forager on its ecosystem. Assessing factors affecting resource selection of large marine herbivores across scales is important because of their potentially large impacts on seagrass community dynamics and historical and current changes in their population sizes and those of their potential predators. I explored the factors (predation risk, resource abundance, quality and identity) affecting resource use of large marine herbivores (green turtles, Chelonia mydas) from the scale of habitat patches to forage species within patches. I used a combination of in-water surveys, aerial drone video transects, baited camera surveys, and seagrass community and nutrient content analyses to provide insights into resource use by turtles in multiple ecological contexts.
In Abaco, The Bahamas I found relatively intact shark populations, including apex predators, relative to other parts of the Caribbean. In the context of healthy predator populations in Abaco, I tested a priori predictions rooted in Ideal Free Distribution (IFD) theory. Green turtles off Abaco deviated from predictions of an IFD determined by the standing stocks of seagrass. Instead, distributions are consistent with predictions of the foraging arena hypothesis with turtles largely restricted to safe habitat patches and selecting locations within these where seagrass N content is relatively high.
Marine invasive species can have detrimental effects on coastal ecosystems and economies. Therefore, understanding the effects of, and factors influencing the rate of spread of the invasive seagrass Halophila stipulacea in the Caribbean is important. In the French West Indies (Guadeloupe, Martinique and St. Martin), I investigated foraging preferences for native versus invasive seagrass species and whether green turtles might facilitate or attenuate the invasion through their choice of habitats and feeding patterns. Green turtle distributions were correlated with native seagrass distributions. Also, despite similar nutrient contents, turtles preferred feeding on native seagrasses irrespective of their relative abundance within a patch. These results suggest that, as predicted by the Enemy Release Hypothesis, green turtles likely facilitate the invasion and spread of the invasive seagrass that may reduce energy flow into turtle populations.
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Kittiwattanawong, Kongkiat. "Biology and Conservation of Green Turtle Chelonia mydas in Thailand." Kyoto University, 2004. http://hdl.handle.net/2433/147779.
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Wabnitz, Colette Catherine Chantal. "Sea turtle conservation and ecosystem-based management with a focus on green turtles (Chelonia mydas) and seagrass beds." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/24239.
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The design of effective species management and recovery plans for sea turtle populations requires targets that are informed by an understanding of knowledge gained at the level of individuals/populations in the context of the wider goal of protecting an ecosystem's structural and functional attributes. In this thesis I present the first detailed investigation of the multiple levels at which sea turtles, particularly green turtles (Chelonia mydas), interact with ecosystems.
I begin by developing a framework for an age-structured population-level assessment of food consumption for hawksbill (Eretmochelys imbricata), loggerhead (Caretta caretta), and green turtles. This entailed construction of species-specific growth models for the western Atlantic, and subsequent integration of results with morphometric, survival, abundance, and food conversion efficiency to derive consumption estimates.
At the ecosystem level, I developed models for the Caribbean and Hawai’í, where green turtles are present at very low abundances and reaching carrying capacity, respectively. In the Caribbean, results showed that green turtle grazing of seagrass substantially altered habitat complexity, reducing the refuge role of seagrass to reef fish and invertebrates, and leading to potentially dramatic changes in species biomass and composition. In Hawai‘i, by feeding on algae, green turtles were found to contribute to the resilience of reefs in the face of disturbance, a functional role that needs to be explicitly included in future studies of reef dynamics. Taken together, these findings highlight the need to consider trophic and indirect interactions in the evaluation of sea turtles’ role within ecosystems.
Accurate and reliable estimates of foraging habitat extent are essential to inform realistic and sustainable turtle recovery targets, particularly given the current degraded state of coastal ecosystems. Using Landsat satellite imagery, I present a novel mapping approach for seagrass habitats at large scales. Such regional initiatives are also urgently needed if the international community is to meet aims to conserve 10 – 30 % of specific habitats. A comparison between reef extent, determined using remote sensing and existing data, showed that discrepancies ranged from + 1,316 % to - 64 %, underlining our limited ability to ascertain progress towards adopted global marine conservation targets based on current data.
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Long, Christopher. "Testing for indirect benefits of polyandry in the Florida green turtle." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5982.
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Behavioral studies in the green turtle (Chelonia mydas) have indicated that promiscuous mating is commonplace. Though it has been shown that there is much variation in the rate of polyandry (females mating with multiple males), the drivers behind polyandry in this species are unknown. It has been speculated, but never demonstrated, that indirect benefits (fitness benefits resulting from offspring genetic diversity) play a role. However, previous tests of this hypothesis have limited scope of inference due to lack of environmental control. In this thesis, I attempted to study the indirect benefits of polyandry in Archie Carr National Wildlife Refuge (ACNWR) green turtles, limiting environmental variation by selecting nests over two week periods in a small subset of the ACNWR. Through the use of highly polymorphic microsatellite markers, I show that 85.7% of ACNWR green turtle females mate with multiple males, the highest rate yet reported for green turtles. I was successful in limiting environmental variation; however, I was unable to make comparisons among nests with one or multiple fathers because of a limited sample size of single father nests. Regardless, my thesis provides preliminary evidence (number of males per nest) that the density of males off Florida's beaches may be relatively high, which is expected to be a driver behind the evolution of polyandry and likely plays a large role both in this population and the prevalence of multiple paternity in green turtles as a whole.M.S.
Masters
Biology
Sciences
Biology
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Gordon, Anita Nancy. "A necropsy-based study of green turtles (Chelania mydas) in south-east Queensland /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18965.pdf.
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Nigro, Olivia De Santis. "Sequencing and characterization of the potentially pathogenic genes of green turtle herpesvirus." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7042.
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Green turtle fibropapilloma (GTFP) is a debilitating and frequently fatal disease of green sea turtles. The etiological agent that causes this disease is unknown, however, recent evidence suggests that a novel green turtle herpesvirus (GTHV) is closely associated with GTFP. Because this virus has not been isolated or propagated in vitro cell culture to date, it is necessary to obtain more genomic information of GTHV in order to establish its pathogenic role in relation to GTFP. Using a modified genomic walking technique, based on inverse polymerase chain reaction (IPCR), a total of 9,032 base pair DNA sequences of the newfound GTHV was sequenced from tumor tissues of green turtles with fibropapillomas. This newly identified DNA fragment contains three potential pathogenic genes from the unique long (UL) region of GTHV: UL29 (DNA binding protein gene), UL28 (assembly protein gene) and UL27 (glycoprotein B gene). The UL29 gene was sequenced through 4 consecutive genomic walks in which a total viral fragment of 4,054 bp of sequence data was obtained. This viral DNA fragment contains the entire open reading frame of the UL29 gene (ORF), which is oriented in the 3' to 5' direction, and encodes the full-length genomic sequence of the DNA binding protein (DBP) gene (3,585 bp) corresponding to a protein of 1,195 amino acid residues. The viral fragment also encodes a partial sequence of the UL28 gene, which is oriented in the 3' to 5' direction as well. Through 2 subsequent genomic walks, the remainder of the UL28 was sequenced in its entirety, as well as a partial ORF of the UL27 gene. The UL28 gene has an ORF of 2,250 bp with a putative amino acid translation of 750 amino acids. Through 1 subsequent genomic walk the entire ORF of the UL27 gene was sequenced. This ORF is 2,551 bp long and overlaps the UL28 genome by 1 bp. The UL27 gene is oriented in the 3' to 5' direction and encodes the putative glycoprotein B (gB) transmembrane peptide, which is 851 amino acids in length. Phylogenetic analysis of GTHV DBP, UL28, and gB genes substantiated that this novel Chelonian herpesvirus is closely related to the Alphaherpesvirinae subfamily. Examination of the translated amino acid sequence further supports this categorization since GTHV DBP comprises a highly conserved zinc finger motif (CXLCX4RX2C) and a putative DNA binding domain, and exhibits high sequence homology to other alphaherpesviruses. The gB peptide also showed high homology to alphaherpesviruses in the extraviral, transmembrane and Cterminal tail regions of the peptide. Cloning and sequencing the genome of this putative herpesvirus will facilitate current understanding of its role in causing GTFP and the development of molecular- and immuno-based methods for the diagnosis and prevention of this devastating disease of green sea turtles.ix, 85 leaves
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Gilbert, Eliza. "JUVENILE GREEN TURTLE (CHELONIA MYDAS) FORAGING ECOLOGY:FEEDING SELECTIVITY AND FORAGE NUTRIENT ANALYSIS." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3337.
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For the endangered green turtle, Chelonia mydas, a fundamental component of recovery and conservation is an understanding of its foraging ecology. Foraging optimality models suggest animals will select resources of high quality over those of low quality. For green turtles, this behavior is important, as sufficient quantities of nutritionally adequate forage items are necessary for growth and reproduction. One intrinsic element in the understanding of green turtle foraging ecology is to identify and document the availability and quality of forage resources preferred by green turtles. The objectives of this study were: 1) determine whether juvenile green turtles showed a feeding preference by comparing prey items in the diet to the availability of those items in the habitat, 2) identify species for which there was selection or avoidance, 3) identify nutritional factors determining selection or avoidance of prey items, and 4) evaluate the nutritional content of the diet. This research was conducted by comparing lavage samples from juvenile green turtles to samples from benthic surveys within the habitat. To determine feeding preference, Ivlev's Electivity Index was used to compare ingested species of algae with those available in the habitat. Nutritional analysis of forage was conducted to identify possible nutrients relating to feeding preference. Juvenile green turtles selectively foraged on Chlorophyta and Rhodophyta. Results indicate that diet selection was based on nutritional content. Both the composite diet and the main diet item, Hypnea spp, had a higher gross energy value, were higher in protein, and lower in fiber than prey items that were avoided. Conservation of green turtles requires effective habitat management, which must be informed by an understanding and evaluation of the habitat. For juvenile green turtles, this study indicates that habitats dominated by Chlorophyta and Rhodophyta may be more important for the health of green turtle populations than habitats dominated by Phaeophyta.M.S.
Department of Biology
Arts and Sciences
Biology
12
Pepi, Vanessa Elisabeth. "Effects of Green Turtle Fibropapillomatosis on the Reproductive Success and Egg Composition of Green Turtles (Chelonia Mydas) Nesting at French Frigate Shoals, Hawaiian Islands National Wildlife Refuge." Thesis, University of Hawaii at Manoa, 2002. http://hdl.handle.net/10125/6956.
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Nesting activity of Hawaiian green turtles was monitored during the 1999 season on Tern Island, French Frigate Shoals, Hawaiian Islands National Wildlife Refuge. Throughout the nesting season, 28 turtles without fibropapillomatosis (FP) and 15 turtles with FP were monitored to determine if reproductive success is affected by FP. Weight (kg) and morphometric measurements (cm) were not significantly different between turtles with and without FP. Although hatch success was not significantly different; clutch sizes of turtles with FP were significantly less (ex < 0.1) than turtles without FP. A subsample of 8 turtles without FP and 7 with FP were observed to determine the potential effects of FP on egg composition. Average egg weight (g) was greater (p<0.01) and the percent crude fat was greater (p<0.05) in turtles with FP than in turtles without FP. Percent moisture content, ash and protein were similar for turtles with and without FP. Percent carbohydrate, estimated by difference, and gross energy calculated based on nutrient composition were not significantly different for turtles with and without FP. Nesting turtles with FP did have low overall tumor scores, but appeared to have slightly impaired reproductive success. Turtles with FP may place more energy (e.g., greater egg weight & fat content) into individual eggs versus turtles without FP to compensate for the decreased clutch size.x, 89 leaves
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Wright, Lucy Isabel. "Insights into the mating systems of green turtle populations from molecular parentage analyses." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3695.
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Gaining a good understanding of marine turtle mating systems is fundamental for their effective conservation, yet there are distinct gaps in our knowledge of their breeding ecology and life history, owing largely to the difficulty in observing these highly mobile animals at sea. Whilst multiple mating by females, or polyandry, has been documented in all marine turtle species, the fitness consequences of this behaviour have not been fully investigated. Furthermore, male mating patterns, operational sex ratios and the number of males contributing to breeding populations are poorly understood, impeding accurate assessments of population viability. In this thesis, I use molecular-based parentage analysis to study, in detail, the genetic mating system of two green turtle (Chelonia mydas) populations. In the focal population in northern Cyprus, I show that, despite exhibiting a strongly female-biased hatchling sex ratio and contrary to our expectations, there are at least 1.3 breeding males to every nesting female. I go on to assess the breeding frequency of male turtles in the population and determine that males do not breed annually at this site, demonstrating that the observed relatively equal sex ratio of breeders is not the result of a few males mating every year, but that the number of breeding males in the population is greater than expected. I show that 24% of nesting females in the population produce clutches with multiple paternity, but do not detect any fitness benefits to polyandrous females, and discuss the potential role of sexual conflict in influencing female mating decisions. Finally, I reveal a high frequency of multiple paternity in green turtle clutches on Ascension Island, one of the largest green turtle rookeries in the world, and discuss possible causes of variation in the level of polyandry among marine turtle populations. The results presented here shed new light on aspects of marine turtle mating systems that are challenging to study, and illustrate the value of molecular data, not only in describing mating patterns, but in elucidating aspects of life history and behaviour that would otherwise be very difficult to ascertain.
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Caldas, Patrício Ana Rita. "Ecology of the green sea turtle (Chelonia mydas L.) in a changing world." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/30061.
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Climate change is threatening biodiversity, causing populations and species to adapt, or otherwise, become extinct. Sea turtles have survived dramatic climate changes in the past, however, due to a history of intense human exploitation, and the current anthropogenic threats, their current resilience may be jeopardized. The main pursuits of this thesis were to i) evaluate the resistance of green turtles to predicted climate change impacts, using a globally significant rookery, in Poilão, Guinea-Bissau, as a case study; and ii) assess key population parameters to inform the conservation management of this resource. As the work developed I additionally had the opportunity to study the dynamics of an emerging disease in a juvenile foraging aggregation from Puerto Rico, which contributed to a broader understanding of resilience in this species. Specifically, I investigate the nest site selection behaviour of green turtles, their nesting environment, and the outcomes for their offspring, at Poilão, and apply this information to infer on the resilience of this population under future scenarios of climate change. I explore the connectivity established by the dispersal of post-hatchlings from Poilão, followed by their recruitment to foraging grounds, to set the geographical context of this major population. Lastly, I model the dynamics of Fibropapillomatosis, which affects juvenile green turtles globally, and examine the potential for disease recovery. The green turtle rookery in Poilão shows some resilience to expected climate change impacts. This significant population likely contributes to all juvenile foraging aggregations along the west coast of Africa, and to some extent to those in South America. Currently, green turtles are capable of recovery from Fibropapillomatosis, however, the incidence of disease may be enhanced by climate change.
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Godley, Brendan J. "Studies on the ecology and conservation of marine turtles, with particular reference to the Mediterranean." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299745.
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Chapman, Rebecca Renee. "A Posthumanist Political Ecology of Conservation in Crisis: reflections from the green sea turtle." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563548525542197.
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Arthur, Karen E. "Ecotoxicology of the cyanobacterium Lyngbya majuscula and health implications for green sea turtles (Chelania mydas) /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18909.pdf.
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Henaghan, Christopher. "Incubation Temperature Effects on Loggerhead (Caretta caretta) and Green (Chelonia mydas) Sea Turtle Hatchling Vigor." Thesis, Florida Atlantic University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13419688.
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Climate change has the potential to expose sea turtle nests to higher temperatures, which may negatively impact sea turtle hatchling vigor. In this study, loggerhead and green hatchlings were sampled from the Boca Raton, Florida beach and via lab incubation, and hatchling vigor was determined. Elevated nest temperatures decreased loggerhead and green turtle hatchling performance and corticosterone levels, with the most significant effects found in hatchlings exposed to maximum incubation temperatures above 35 °C during late development. Lab-incubated loggerhead post-hatchling corticosterone levels and growth rates were also determined. The differences seen in corticosterone levels with overall nest incubation temperatures, mean temperatures during early, middle or late stages of development, and its negative correlation with hatchling performance improves our understanding of the underlying physiological mechanisms linking elevated incubation temperatures and sub-lethal physiological effects that may significantly impact hatchling survival, a critical step for sea turtle conservation in south Florida and elsewhere.
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Long, Tonya Michele. "An assessment of sea turtle nesting behavior in relation to hurricane- and restoration-induced beach morphodynamics." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4527.
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Coastal habitats are highly dynamic and vulnerable to landscape-level disturbances such as storms and restoration projects. Along the east coast of Florida these areas are particularly valuable as they provide significant nesting habitat for two sea turtle species, the threatened loggerhead (Caretta caretta) and the endangered green turtle (Chelonia mydas). This coast was heavily impacted by three major hurricanes in 2004 and in some areas by large restoration projects in 2005. Recent remote sensing methods allow for broad evaluation of the shoreline and thus the ability to assess sea turtle nesting habitat at a landscape scale. I collected nesting data for southern Brevard County, Florida from 1989-2005 and for Canaveral National Seashore, Florida from 1995-2005. I used LiDAR (Light Detection and Ranging) and IfSAR (Interferometric Synthetic Aperture Radar) remote sensing to map sea turtle nesting habitat in both areas following the 2004 hurricanes and any subsequent restoration. Canaveral National Seashore underwent no restoration while southern Brevard County received extensive restoration. Topographic variables (e.g., total sand volume, width, and slope) derived from the remote sensing data were compared across three time periods (pre-hurricane, post-hurricane, and recovery period) and I compared nesting success data from 2004 to 2005. I built regression models for 2004 and 2005 to determine which topographic features influenced loggerhead and green turtle nesting the most. Green turtle nesting success declined from 2004 to 2005 only in highly restored areas while loggerhead nesting sucess declined throughout. Hurricanes caused a reduction in most of the topographic variables and restoration predominantly impacted aspects of the beach profile (e.g. slope and width).; Loggerheads responded to profile characteristics (e.g. upper and lower beach slopes) though green turtles showed no consistent response to topography. The results indicate that both loggerheads and green turtles are sensitive to beach restoration, although loggerhead nesting is more influenced by beach morphology and green turtle nesting may be influenced more by other dune features such as vegetation cover.ID: 028916930; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2010.; Includes bibliographical references (p. 67-72).
M.S.
Masters
Department of Biology
Sciences
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Campbell, Cathi Lynn. "Population assessment and management needs of a green turtle, Chelonia mydas, population in the western Caribbean." [Gainesville, Fla.]: University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000657.
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Tiwari, Manjula. "Density-dependent effects on hatchling production in the green turtle nesting population in Tortuguero, Costa Rica." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0005620.
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Brock, Kelly. "EFFECTS OF A SHORE PROTECTION PROJECT ON LOGGERHEAD AND GREEN TURTLE NESTING ACTIVITY AND REPRODUCTION IN BREVARD COUNTY, FLORID." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2946.
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Marine turtle reproductive success is strongly correlated with the stability and quality of the nesting environment. Because females show fidelity to key nesting beaches, the management and physical characteristics of these beaches directly affect future generations of marine turtles and may be essential for the recovery of these threatened and endangered species. The impacts of beach restoration on loggerhead turtles (Caretta caretta) and on green turtles (Chelonia mydas) were investigated. Previous studies concerning beach nourishment projects have focused on loggerhead turtles. I compared data between nourished and non-nourished areas and between loggerhead and green turtles. I found, at one season post-nourishment, negative effects on nesting success and no significant effect on reproductive success for both loggerheads and established the same relationships with green turtles. Physical attributes of the fill sand, which did not facilitate acute scarp formation or severe compaction, did not physically impede turtles in their attempts to nest. Instead, the decrease in nesting success was attributed to an absence of abiotic and or biotic factors that cue nesting behavior. The increase in loggerhead nesting success rates during the second season post-nourishment was attributed to the equilibration process of the seaward crest of the berm. After the beach was restored, both species of turtles placed nests significantly farther from the water in the nourished area than in the non-nourished area. Green turtles nested on or near the dune and loggerheads nested on the seaward crest of the berm. The tendency of loggerheads to nest closer to the water resulted in more loggerhead than green turtle nests being "washed out" by erosion during the equilibration process. There was a significant increase in hatching success only for loggerheads when wash outs were excluded, thus illustrating the importance of nest placement and the detrimental effects of the equilibration process to the reproductive success of loggerheads. A decrease in reproductive output occurred during the first season post-nourishment. The reduction in the estimated total number of hatchlings produced (reproductive output) was a consequence of decreased nesting success lowering nest numbers. This reduction demonstrates that, regardless of similar reproductive success rates, marine turtles incurred net losses during the first season following nourishment. These results further reveal the impacts of decreased nesting success and the importance of minimizing excessive non-nesting emergences associated with beach nourishment.M.S.
Department of Biology
Arts and Sciences
Biology
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Roberts, Kelsey. "Weather patterns associated with green turtle hypothermic stunning events in St. Joseph Bay and Mosquito Lagoon, Florida." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4836.
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January of 2010 brought record-breaking cold temperatures to Florida. Such freeze events can upset vulnerable populations of marine life and other species that rely on stable water temperatures. Sea turtles are one group of species that are particularly susceptible to abrupt drops in water temperature. When water temperatures drop below 10°C, a mass hypothermic stunning, or cold-stunning, event for sea turtles can be expected, with many debilitated turtles washing onshore with a very limited time window to be rehabilitated (Foley et al. 2007). The species of sea turtle that appears to cold-stun with the most frequency is the green turtle, especially juveniles. The green turtle represented the vast majority of marine turtles that were rescued during the 2010 cold-stun event.
Therefore, accurate weather pattern recognition of marine cold snaps, or freezes, can alert sea turtle rescue groups and rehabilitation facilities in advance of any event, improving their readiness and response times, and ultimately preventing population declines. The proposed research fills this need by providing a qualitative analysis of select years for comparable atmospheric processes that could result in moderate to severe hypothermic stunning events. The 2010 event, along with other significant events, were examined using in situ air temperature, water temperature and wind data near two locations in Florida where hypothermic stunning events occurred: St. Joseph Bay and Mosquito Lagoon. These atmospheric parameters were represented graphically, depicting how each variable contributed to shaping an event.
Cold stunning events were found to be primarily driven by frigid air temperatures and a subsequent decrease in water temperatures. Differences between the two event classifications, moderate and severe, are contingent upon the duration of the cold spell, not necessarily how quickly the water temperature dropped below the 10°C threshold value. Results suggest that repeated, quick exposure to cold air temperatures may influence the severity of a hypothermic stunning event. This research could be utilized in the formation of a forecasting model or strategy to efficiently alert the Florida Sea Turtle Stranding and Salvage Network (STSSN) to a potential sharp drop in water temperatures and, consequently, many debilitated sea turtles.
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Balfour, Martha. "Abiotic Differences Between Green Turtle (Chelonia Mydas) Nests in Natural Beach and Engineered Dunes: Effects on Hatching Success." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2439.
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Habitat loss is among the biggest threats to conservation worldwide, so habitat restoration plays an increasing role in endangered species management. This is especially true for species with high site fidelity, such as nesting marine turtles. Sand replenishment is commonly used to restore coastal beaches after severe erosion events, and may affect marine turtles and other species that live or reproduce in that habitat. I investigated how abiotic characteristics of sand used in a dune restoration project at Archie Carr National Wildlife Refuge, Florida, affected reproduction of the federally-endangered green turtle (Chelonia mydas). Sand structure and composition can affect egg development and hatching success by altering nest conditions, with nests in fine-grain or very coarse sand suffering decreased hatching success. I determined that calcium carbonate content (27.0% ± 1.4 SE vs. 15.1% ± 3.8 SE), moisture content (3.29% ± 0.26 SE vs. 4.59% ± 0.25 SE), and grain size (427.53 μm ± 14.1 SE vs. 274.66 μm ± 29.1 SE) differed significantly between natural and restored dunes. Hatching success of green turtles (44.7% ± 6.2 SE vs. 65.8% ± 5.3 SE) was significantly lower on restored dunes compared to natural dunes with an estimated loss of 22,646 hatched eggs. Hatching success also decreased as the nesting season progressed. These results demonstrate the importance of regulating fill material used in beach restoration projects; substrate characteristics are easily evaluated and can significantly influence marine turtle hatching success.M.S.
Department of Biology
Sciences
Biology MS
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Baptistotte, Cecilia. "Caracterização espacial e temporal da fibropapilomatose em tartarugas marinhas da costa brasileira." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-11032008-153152/.
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Fibropapilomatose (FP) é uma doença caracterizada por múltiplas massas de tumores cutâneos variando de 0,1 a mais de 30 cm em diâmetro. Afeta primariamente tartarugas-verdes (Chelonia mydas), mas também outras espécies de tartarugas marinhas ao redor do mundo. O objetivo deste estudo é, através de dados já sistematicamente coletados pelo Programa Brasileiro de Proteção, Pesquisa e manejo das Tartarugas Marinhas - Projeto TAMAR-IBAMA, caracterizar, no tempo e no espaço, a ocorrência desta doença em tartarugas marinhas na costa brasileira, entre os anos de 2000 a 2005. As tartarugas encontradas, vivas ou mortas, foram identificadas, medidas e examinadas quanto à presença ou ausência de tumores. Nesse período foram examinadas 10.170 tartarugas marinhas, sendo 1.243 tartarugas-de-pente, (Eretmochelys imbricata), das quais 2 apresentaram tumores; entre as 250 tartarugas- cabeçudas, (Caretta caretta), 5 apresentaram tumores; entre as 288 tartarugas-oliva (Lepidochelys olivacea), 3 apresentaram tumores; nenhuma das 30 tartarugas-gigantes, (Dermochelys coriacea) examinadas tinham tumores. A maior parte dos registros (82,20 %; 8.359 de 10.170) correspondeu a tartarugas-verdes (Chelonia mydas), das quais 1.288 apresentavam tumores. Foram coletadas amostras de tumores de 80 tartarugas para análise histopatológica; todas foram positivas para fibropapilomatose. A média da prevalência nacional geral para Chelonia mydas foi de 15.41%; apenas nas áreas costeiras a doença foi verificada. Nenhuma ocorrência foi registrada nas ilhas oceânicas do Atol das Rocas e do Arquipélago de Fernando de Noronha. Os resultados das freqüências de tumores por estado foram: Bahia, 15,81% (211/1335); Ceará, 36,94% (181/490); Espírito Santo, 27,43% (469/1710); Pernambuco-Arquipélago de Fernando de Noronha, 0,00% (0/501); Rio de Janeiro, 5,96% (9/151); Rio Grande do Norte-região costeira, 31,43% (33/105); Rio Grande do Norte-Atol das Rocas, 0,00% (0/486); Sergipe, 18,46% (12/65); São Paulo, 10,73 % (371/3456). Os animais afetados variaram de juvenis com comprimento curvilíneo de carapaça (CCC) mínimo de 30,0 cm, subadultos a adultos com máximo de 112 cm. A prevalência de tumores associado a fibropapilomatose aumentou com o CCC até 80,0 cm e decresceu abruptamente. A caracterização da doença foi realizada com um grupo de 202 tartarugas verdes afetadas em uma agregação no Estado do Espírito Santo. Nesse grupo, o número de tumores variou de 1 a 179 tumores em um único animal, tendo como média 21 tumores por tartaruga afetada. 72,5 % dos tumores estavam localizados na região anterior corpórea do animal, 25,2% na região posterior e 2,3% na carapaça e plastrão. Nenhuma tartaruga apresentou tumores na cavidade oral. Para análise de escore de tumor em tartarugas afetadas com FP, o escore de tumor 1 e 2 foi predominante, com 40,61% (80 de 197) e 51,27% (101 de 197) respectivamente. Apenas 8,12% (16 de 197) das tartarugas tiveram escore de tumor 3.Fibropapilomatosis (FP) is a disease characterized by multiple masses of cutaneous tumors varying from 0,1 to more than 30 cm in diameter. It has affected primarily green turtles (Chelonia mydas), but also other species of sea turtles around the world. The aim of this study is, through the data already systematically collected by the Brazilian Sea Turtle Protection, Research and Management Program - Projeto TAMAR - IBAMA to characterize the occurrence of this disease in marine turtles along the Brazilian coast to within time and space, from 2000 to 2005. Turtles found alive or dead were identified as for the species, measured and examined as for the presence or absence of tumors. 10.170 sea turtles were examined: 1.243 of them were Hawksbills (Eretmochelys imbricata), two of which showed tumors; five of the 250 loggerhead turtles (Caretta caretta) and three of 288 olive ridley\'s turtles (Lepidochelys olivacea), showed tumors; none of the 30 leatherback (Dermochelys coriacea) carried tumors. Mostly of the records, (82,20%; 8.359/10170) corresponded to green turtles (Chelonia mydas), 1.288 of which had tumors. Samples of tumors were collected from 80 turtles for histopathologycal analysis; all examined samples were positive for fibropapillomatosis. The average nationwide tumor prevalence in Chelonia mydas was 15.41%; the disease was detected only in coastal areas: no occurrence was recorded for the oceanic islands of Atol das Rocas and Fernando de Noronha Archipelago. The tumor frequencies by state were: Bahia, 15,81% (211/1335); Ceará, 36,94% (181/490); Espírito Santo, 27,43% (469/1710); Pernambuco - Archipelago of Fernando de Noronha, 0,00% (0/501); Rio de Janeiro, 5,96% (9/151); Rio Grande do Norte- coastal area, 31,43% (33/105); Rio Grande do Norte - Atol das Rocas, 0,00% (0/486); Sergipe, 18,46% (12/65); São Paulo, 10,73% (371/3456). The affected animals varied from juvenile, with minimum curved carapace length (CCC) 30,0 cm to sub-adults, adults with a maximum 112 cm. The prevalence of tumours associated to fibropapillomatosis increased with CCC up to 80,0 cm and then decreased abruptly. The number of tumors in 202 affected green turtles from an aggregation in the state of Espírito Santo varied from 1 to 179 tumors in a single animal, with an average of 21 tumors per affected turtle. 72,5% of tumors were located in the anterior half of the animal\'s bodies, 25,2% in the posterior area, 2,3% on the shell and plastron. No turtle had tumors in the oral cavity. A predominance of turtles was registered with tumors score 1, 40,61% (80 of 197) and score 2, 51,27% (101/197). Only 8,12% (16/197) of the turtles that had score 3. For analysis of tumor score in affected turtles with FP, the tumors score 1 and 2 was predominant, with (40,61%; 80 of 197) and (51,27%; 101/197) respectively. Only 8,12 % (16/197) of the turtles attained tumors score 3.
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Stokes, Kimberley Laura. "Ecology of marine turtles under climate change." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/21847.
Full textAbstract:
Climate change threatens to disrupt biological systems around the globe, sparking debate over natural capacity for adaptation in a fragmented landscape. Marine turtles are evolutionarily ancient and have survived millions of years of prehistoric climate change, but are threatened by the rapidity of modern warming and a history of severe overexploitation that has left most populations depleted. This thesis explores a nesting aggregation of the green turtle (Chelonia mydas) in northern Cyprus, where a longitudinal programme of both intensive and extensive monitoring enables insight into individual and population level parameters and processes. Nesting on the two coastlines covered by this project is in the early stages of recovery, possibly in response to exhaustive nest protection efforts over the last twenty years. Saturation tagging at one key site allows us to confirm that recruitment of new breeders is an important driver of this trend, and that average clutch frequency has remained stable around three nests per female per year, validating nest-count derived abundance estimates at a regional scale. Concern has been raised, however, regarding recent changes in fishing practices which are impacting the local juvenile neritic phase, which may have a lagged effect on the recovery of this nesting population. A collaborative tracking effort including all other countries with major nesting in the Mediterranean allows us to identify major foraging grounds for this species, with two hotspots accounting for >50% of tracked individuals, as well as coastal and pelagic seasonal corridors of high use. Bycatch levels and mortality rates for turtles in these key areas are largely unknown and should be prioritised for investigation. Hatchling sex ratios from the main study beach are extremely female-biased (estimated 97% female for the twenty year period 1993-2012). A 1oC rise in average incubation temperatures threatens near complete hatchling feminisation on this beach, whilst a 2oC rise could reduce hatch success to less than 50%. Thermal effects on hatchling morphometrics are evident, with a 1oC rise in temperature reducing average length, width and weight by 1%, 2% and 3% respectively. More favourable incubation conditions were found early in the season, in deeper nests laid by larger females, and on beaches of lighter sand. In contrast, adult sex ratios at the main site are male-biased, posing questions regarding sex-specific survival rates and optimal hatchling sex ratios. A phenological shift towards earlier nesting is demonstrated for the first time in this species, and could potentially ameliorate warming effects. Carry-over climate forcing effects from the foraging ground influence the breeding frequency of individuals, driving population level responses in annual magnitude of nesting. This work emphasises the utility and necessity of long-term individual-based monitoring programmes in elucidating population trends and climate responses in iteroparous species with non-annual breeding.
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Earney, Megan A. "Investigating the Effect of Mechanical Beach Cleaning on Nesting, Hatching and Emergence Success of Loggerhead (Caretta caretta) and Green (Chelonia mydas) Sea Turtles in Broward County, Florida." NSUWorks, 2017. http://nsuworks.nova.edu/occ_stuetd/454.
Full textAbstract:
Sea turtles face many threats to their populations globally. Loggerhead sea turtles (Caretta caretta) and green sea turtles (Chelonia mydas) are listed by the International Union for the Conservation of Nature Red List as Endangered. In Florida, loggerhead and green sea turtles nest along the coastline during April-September. Mechanical beach cleaning is an aesthetic service performed daily on some beaches in Florida to clean the wrack line and/or the entire beach of debris. Alterations made to beaches by methods such as mechanical beach cleaning have the potential to impact sea turtle nesting, hatching, and emergence success. Generalized linear mixed models were performed to investigate the impacts of mechanical beach cleaning on nesting, hatching and emergence success of loggerhead and green turtles from 1997-2015 in Broward County, Florida. The results showed mechanical beach cleaning had an effect on nesting success, however, hatching and emergence success were not affected by mechanical beach cleaning. These results indicate that mechanical beach cleaning cannot solely be used to determine sea turtle management or conservation guidelines in Broward County.
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Seminoff, Jeffrey Aleksandr. "Biology of the East Pacific green turtle, Chelonia mydas agassizii, at a warm temperature feeding area in the Gulf of California, Mexico." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284231.
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I studied the East Pacific green turtle, Chelonia mydas agassizii , at the Bahia de los Angeles foraging grounds of the Gulf of California from July 1995 to October 1999. Entanglement nets were used to capture 153 green turtles among 16 capture sites. Pooled straight carapace length (SCL; mean ± SE) was 75.1 ± 0.79 cm. Though there was no significant variation in mean SCL among years, there was evidence of a difference in mean SCL among capture sites. Most of the population (58%) consisted of immature turtles but did not differ significantly from a 1:1 immature:adult ratio. Pooled adult sex ratio (F:M) was biased toward probable females (2.70:1.00) and differed substantially from a 1:1 ratio. Approximately 5% of the population showed signs of anthropogenic-derived injuries ranging from missing flippers to boat impact scars. I collected gastric lavage samples from 101 green turtles and fecal samples from a subset of 45 turtles. Digestive tract contents were analyzed from seven stranded carcasses. The primary alga recovered in diet samples was Gracilariopsis lemaneiformis. Other major diet items included the green algae Codium sp. and Ova lactuca. Animal matter was found in all sample types. Tube worms (Sabellidae), sponges (Porifera), sea hares (Aplysia vaccaria), and sea pens ( Ptilosarcus undulatus) were the most commonly ingested invertebrates. I studied home range sizes and movements of 23 C. m. agassizii . Mean minimum convex polygon home range area was 1,801 ha. Kernel density estimates (95%) of home range area had a mean of 1,545 ha. Home range length averaged 7,548 m. Mean 24-h vagility was 9,535 m. Diurnal and nocturnal movements were evident. Turtles exhibited a bimodal pattern in which they foraged in nearshore algae pastures during evening and night hours and moved to offshore and/or insular resting sites by midmorning. This study indicates that Bahia de los Angeles is an important foraging and developmental habitat for C. m. agassizii. Management efforts should focus on reducing human disturbance and the use of entanglement nets in the entire bay. In such efforts it is essential that local inhabitants are provided with alternatives that encourage sustainable marine resource use and economic progress.
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Hays, Allison Whitney. "Determining the impacts of beach restoration on loggerhead (Caretta caretta) and green turtle (Chelonia mydas) nesting patterns and reproductive success along Florida's Atlantic coast." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5295.
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Artificial beach nourishment, the most common method to mitigate coastal erosion in the United States, is also considered the most ecologically friendly alternative for shoreline stabilization. However, this habitat alteration has the potential to impact nesting marine turtles and developing hatchlings. The first objective of this study was to determine how nourishing beaches with two different design templates affects loggerhead (Caretta caretta) and green turtle (Chelonia mydas) nesting success, the ratio of nests to the total number of nests and non-nesting emergences, and reproductive success, the ratio of hatched and emerged hatchlings to the total number of eggs deposited. Two types of restoration designs exist along the southern Brevard County, FL coastline, which supports some of the highest density loggerhead and green turtle nesting worldwide. Since 2005, approximately 35 kilometers of beach have undergone 1) full-scale restoration (typically called nourishment), where sand was added above and below the mean high tide line (2005, 2010) or 2) dune restoration, where sand was placed on the dune (2005, 2006, 2008, 2009). To quantify the effects of these restoration types, we used a Before-After-Control-Impact-Paired Series (BACIPS) model, which tests for significance between the difference in nesting success rates at the impact (engineered) and control sites (natural beach) before and after restoration ([delta]). For loggerheads, there was a significant difference in [delta] after dune restoration during the years of construction (2005, 2006, 2008, and 2009; p<0.001) and one year post-construction (2007; p<0.05 and 2010; p<0.001). After full-scale restoration, there was a significant difference in [delta] during the years of construction (2005 and 2010; p <0.001) and one year post-construction (2006; p<0.001). For green turtles, there was a significant difference in [delta] after dune restoration during two of the four years of construction (2006; p<0.05 and 2008; p<0.01) and one of the two one-year post-construction years (2010; p<0.05). After full-scale restoration, the significant difference in [delta] lasted every season (2005-2010; p<0.001). There were no significant differences in [delta] for loggerhead or green turtle reproductive success rates after either type of restoration. The second objective was to use the different restoration designs to study what beach characteristics function as loggerhead nesting cues to explain why altering the beach decreases nesting success rates. We examined beach elevation and slope, sand moisture content, sand grain size, beach width, and distance traveled. Logistic regression model selection found all variables were important (R2=0.75). Further examination of trends, with each crawl divided into quarters, found beach slope served as a nesting cue. In all study sites except one, when turtles false crawled, the beach flattened out in the final quarter of the crawl. Conversely, in nesting emergences, the final quarter rose at a steeper slope than the previous quarter. Additionally, model selection found variables important in nest site selection were also important in hatching (R2=0.44) and emergence (R2=0.45) success. These results offer new insight into how and why marine turtle nesting patterns change after artificial nourishment, providing information necessary to nourish beaches in a more “turtle-friendly” manner.ID: 031001543; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: John Weishampel.; Co-adviser: Llewellyn Ehrhart.; Title from PDF title page (viewed August 22, 2013).; Thesis (M.S.)--University of Central Florida, 2012.; Includes bibliographical references (p. 84-90).
M.S.
Masters
Biology
Sciences
Biology
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Jordão, Juliana Costa. "Estrutura populacional e história demográfica da tartaruga-verde (Chelonia mydas) no Atlântico Oeste." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/41/41131/tde-24032014-103353/.
Full textAbstract:
As tartarugas marinhas são répteis de vida longa que realizam extensas migrações entre áreas de alimentação e desova, resultando em estágios sucessivos de mistura e isolamento de estoques genéticos, espacial e temporalmente. A tartaruga-verde (Chelonia mydas) está ameaçada de extinção, e é fundamental entender sua dinâmica populacional e distribuição para o manejo e conservação da espécie. O objetivo deste estudo foi analisar a diversidade genética, estrutura populacional, origens dos indivíduos e história demográfica de C. mydas em três locais do Oceano Atlântico (estado do Rio de Janeiro, Brasil - área de alimentação; Guadalupe e Guiana Francesa - áreas de desova), com base em sequências da região controle do DNA mitocondrial (mtDNA) e 10 loci de microssatélites. As análises de mtDNA demonstraram que a área amostrada no Brasil tem perfil genético semelhante às outras áreas de alimentação da costa brasileira. De maneira semelhante, o perfil genético das duas áreas de desova é bastante similar ao de outros sítios reprodutivos na região do Caribe. As análises de estoque misto revelaram que os indivíduos juvenis no Brasil são provenientes principalmente da Ilha Ascensão, Guiana Francesa e Guiné Bissau. Os microssatélites detectaram estrutura genética entre as três populações, apesar de haver um fluxo de migrantes entre elas, especialmente de indivíduos da Guiana Francesa em direção ao Brasil e Guadalupe. Guiana Francesa, Guadalupe e Brasil apresentaram declínio populacional severo, detectado pelos microssatélites. Apesar da distribuição global, as populações de tartarugas-verdes estão sujeitas a diferentes pressões nos habitats que ocupam, e é importante entender quais populações estão ameaçadas. Este estudo enfatiza a importância da conectividade entre áreas de alimentação e desova que podem estar amplamente distribuídas de acordo com oportunidades ou restrições ecológicas, adicionando informações a respeito da dispersão e a dinâmica de tartarugas-verdes que frequentam o Oceano AtlânticoSea turtles are reptiles with a long lifespan that undertake wide-ranging migrations through feeding and nesting sites, resulting in successive stages of mixing and isolating genetic stocks, both spatially and temporally. The green sea turtle (Chelonia mydas) is threatened with extinction, and it is essential to understand its population dynamics and distribution in order to manage and preserve the species. The aim of this study was to analyze the genetic diversity, population structure, natal origins and demographic history of C. mydas in three sites in the Atlantic Ocean (Rio de Janeiro state, Brazil - feeding ground; Guadeloupe and French Guiana - nesting sites), based on sequences of the mitochondrial DNA (mtDNA) control region and 10 microsatellites loci. The mtDNA analyses demonstrated that Brazilian samples have the same genetic profile of others collected in feeding grounds in the Brazilian coast. Similarly, the genetic profile of the nesting sites has resemblances to others in the Caribbean region. The mixed stock analyses revealed that most of the juveniles in Rio de Janeiro state come from Ascension Island, French Guiana and Guinea Bissau. Microsatellites detected genetic structure among the three populations, even with migration flows, especially in individuals from French Guiana to Brazil and Guadeloupe. French Guiana, Guadeloupe and Brazil presented a severe population decline, detected by the microsatellites analyses. Despite the worldwide distribution, green sea turtle populations undergo different pressures at the habitats they occupy, and it is important to understand which populations are threatened. This study emphasizes the importance of connecting nesting and feeding areas that can be widely distributed according to ecological opportunities or constraints, adding information on dispersion and population dynamics of green sea turtles on Atlantic Ocean
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Burkholder, Derek A. "Top Down Control in a Relatively Pristine Seagrass Ecosystem." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/799.
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The loss of large-bodied herbivores and/or top predators has been associated with large-scale changes in terrestrial, freshwater, and marine ecosystems around the world. Understanding the consequences of these declines has been hampered by a lack of studies in relatively pristine systems. To fill this gap, I investigated the dynamics of the relatively pristine seagrass ecosystem of Shark Bay, Australia. I began by examining the seagrass species distributions, stoichiometry, and patterns of nutrient limitation across the whole of Shark Bay. Large areas were N-limited, P-limited, or limited by factors other than nutrients. Phosphorus-limitation was centered in areas of restricted water exchange with the ocean. Nutrient content of seagrasses varied seasonally, but the strength of seasonal responses were species-specific. Using a cafeteria-style experiment, I found that fast-growing seagrass species, which had higher nutrient content experienced higher rates of herbivory than slow-growing species that are dominant in the bay but have low nutrient content. Although removal rates correlated well with nutrient content at a broad scale, within fast-growing species removal rates were not closely tied to N or P content. Using a combination of stable isotope analysis and animal borne video, I found that green turtles (Chelonia mydas) – one of the most abundant large-bodied herbivores in Shark Bay – appear to assimilate little energy from seagrasses at the population level. There was, however, evidence of individual specialization in turtle diets with some individuals foraging largely on seagrasses and others feeding primarily on macroalgae and gelatinous macroplankton. Finally, I used exclusion cages, to examine whether predation-sensitive habitat shifts by megagrazers (green turtles, dugongs) transmitted a behavior-mediated trophic cascade (BMTC) between sharks and seagrasses. In general, data were consistent with predictions of a behavior-mediated trophic cascade. Megaherbivore impacts on seagrasses were large only in the microhabitat where megaherbivores congregate to reduce predation risk. My study highlights the importance of large herbivores in structuring seagrass communities and, more generally, suggests that roving top predators likely are important in structuring communities - and possibly ecosystems - through non-consumptive pathways.
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Reece, Joshua. "HISTORICAL RESPONSES OF MARINE TURTLES TO GLOBAL CLIMATE CHANGE AND JUVENILE LOGGERHEAD RECRUITMENT IN FLORIDA." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3223.
Full textAbstract:
Marine turtle conservation is most successful when it is based on sound data incorporating life history, historical population stability, and gene flow among populations. This research attempts to provide that information through two studies. In chapter I, I identify historical patterns of gene flow, population sizes, and contraction/expansion during major climatic shifts. In chapter II, I reveal a life history characteristic of loggerhead turtles previously undocumented. I identify a pattern of juvenile recruitment to foraging grounds proximal to their natal nesting beach. This pattern results in a predictable recruitment pattern from juvenile foraging ground aggregations to local rookeries. This research will provide crucial information to conservation managers by demonstrating how sensitive marine turtles are to global climate change. In the second component of my research, I demonstrate how threats posed to juvenile foraging grounds will have measurable effects on rookeries proximal to those foraging grounds. The addition of this basic life history information will have dramatic effects on marine turtle conservation in the future, and will serve as the basis for more thorough, forward-looking recovery plans.M.S.
Department of Biology
Arts and Sciences
Biology
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Chambault, Philippine. "Distribution et comportement de plongée des tortues marines de Guyane française sous l'influence des structures océanographiques." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ030/document.
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La forte hétérogénéité de l'écosystème marin se traduit par une production inégale des ressources sur un large éventail d'échelles spatio-temporelles, qui conditionne par conséquent les déplacements des tortues marines. Considéré comme l’un des plus dynamiques au monde, le plateau des Guyanes est une région très complexe d'un point de vue océanographique et qui héberge trois des sept espèces de tortues marines présentes dans le monde (la tortue olivâtre, la tortue verte et la tortue luth). L'objectif de cette thèse était de comprendre comment les contraintes océanographiques peuvent-elles influencer les déplacements en mer de ces trois espèces. Le déploiement de 55 balises satellites sur des femelles reproductrices en Guyane française a permis de fournir des informations sur leurs trajectoires, sur leur comportement de plongée et sur les caractéristiques de leur environnement. Notre étude a mis en évidence une forte plasticité comportementale interspécifique qui semble être principalement dictée par les traits reproducteurs, les stratégies de reproduction, les conditions locales de l'habitat ou encore les adaptations physiologiquesThe strong heterogeneity of the marine ecosystem leads to a patchy distribution of the resources in time and space, shaping therefore the movements of sea turtles. Considered as the most dynamic ecosystem in the world, the Guiana shield is a highly dynamic system which hosts three of the seven sea turtle species in the world (the olive ridley, the green turtle and the leatherback turtle). The aim of this thesis was to understand how the oceanographic constraints can influence the at-sea movements of these three species during the reproduction and the migration phases. The deployment of 55 satellite tags on adult females in French Guiana provided information on their trajectories, their diving behavior and on the environment encountered. Our study shows a strong behavioral plasticity between species, which seems to be mainly dictated by the reproductive traits and strategies, the local conditions of the habitat and the physiological adaptations
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Caderas, Jenna. "Beach Nourishment: Effects on the Hatching & Emergence Success Rates of Leatherback (Dermochelys coriacea), Loggerhead (Caretta caretta), and Green (Chelonia mydas) Sea Turtles." NSUWorks, 2016. http://nsuworks.nova.edu/occ_stuetd/417.
Full textAbstract:
Broward County, Florida is a popular tourism destination. Due to its popularity, much of the shoreline has been modified and natural habitats were replaced with infrastructure such as houses, condominiums, resorts, and restaurants. The same Broward County beaches utilized by tourists and residents are important for three species of nesting sea turtles, including the Leatherback, Dermochelys coriacea, Loggerhead, Caretta caretta, and Green, Chelonia mydas, Turtles. The Broward County Sea Turtle Conservation Program (BCSTCP) collects yearly data in order to study these endangered reptiles. Increased anthropogenic effects including further coastal development (public & private), public beach events, public beach access, as well as natural events, have caused these important nesting beaches to erode and narrow. In an effort to control this erosion damage, Broward County has performed a number of beach nourishment projects. This study found yearly fluctuations in sea turtle hatching and emergence success rates, and years of beach nourishment projects significantly decreased these rates. Yearly hatching data available from Broward County concludes that beach nourishment, as well as hurricanes and tropical storms cause decreases in sea turtle hatching and emergence success rates in Broward County. Additionally, nest depth and sea turtle size increases the hatching and emergence success rates from females that are not too large or too small that nest in Broward County.
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Rossi, Silmara. "Análise da atividade de leucócitos e de bifenilas policloradas aplicada ao estudo da fibropapilomatose em Chelonia mydas (Testudines, Cheloniidae) (Linnaeus 1758)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-30042014-102858/.
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A tartaruga verde (Chelonia mydas) é uma tartaruga marinha que se alimenta e nidifica em locais da costa brasileira, ilhas e atóis. Esta espécie tem sido acometida pela fibropapilomatose (FP), doença considerada como uma das mais importantes ameaças à sua sobrevivência e caracterizada por tumores cutâneos benignos. A etiologia é multifatorial e complexa, possivelmente havendo relação entre Chelonid Fibropapilloma-associated Herpesvirus, fatores ambientais e genéticos. Foram estudadas 133 tartarugas verdes com e sem tumores provenientes de cinco áreas brasileiras: Florianópolis/SC, Ubatuba/SP, Vitória/ES, Almofala/CE e Fernando de Noronha/PE. Foram obtidos dados de biometria (comprimento curvilíneo da carapaça-CCC, massa corporal-MC e índice de condição corporal-ICC), tamanho (classificado por categorias A, B, C e D), quantidade e localização anatômica dos tumores, além da colheita de amostra sanguínea. Os objetivos foram (1) avaliar a atividade dos leucócitos por citometria de fluxo (fagocitose e burst oxidativo); (2) investigar a presença de sete congêneres de bifenilas policloradas (PCBs) e (3) estabelecer correlações entre PCBs e a atividade dos leucócitos. Houve diferenças no CCC entre tartarugas sem tumores de acordo com a área de estudo, na MC e no ICC entre animais acometidos ou não capturados em Ubatuba. Foram quantificados e classificados 1033 tumores de 50 tartarugas verdes, sendo que a quantidade por tartaruga variou de 1 a 61 e a maior parte foi classificada nas categorias de tamanho A (446 tumores) e B (520 tumores) e na região anterior (669 tumores). Foi observada diferença significativa nas concentrações do congênere PCB 138 entre tartarugas com e sem FP capturadas em Vitória. Animais acometidos tiveram maiores concentrações de todas as PCBs quantificadas, exceto as tartarugas verdes capturadas em Vitória no caso dos congêneres PCBs 118, 138, 153 e 180. PCB 138 foi quantificado em maior concentração nas amostras e PCB 180 em níveis menores. Não foram observadas correlações significativas entre concentrações de PCBs e atividade celular. A FP tem sido amplamente pesquisada e os estudos que visam estabelecer correlações entre poluentes químicos e saúde animal são extremamente importantes, pois podem contribuir para novas direções nos planos de ação para conservação.The green sea turtle (Chelonia mydas) feeds and nests in Brazilian coast, islands and atolls. This species has been affected by fibropapillomatosis (FP), disease considered one of the most important threats to its survival and characterized by benign skin tumors. The etiology is multifactorial and complex, possibly having relation between Chelonid Fibropapilloma-associated Herpesvirus, environmental and genetic factors. Were studied 133 green sea turtles with and without FP from five Brazilian areas: Florianópolis/SC, Ubatuba/SP, Vitória/ES, Almofala/CE and Fernando de Noronha/PE. Were taken biometric data (curved carapace length-CCL, body mass-BM and body condition index-BCI), as well as size (classified by categories A, B, C and D), numbers and anatomical distribution of tumors, besides blood sample collection. The aims were (1) to assess leukocytes activity by flow cytometry (phagocytosis and oxidative burst); (2) to investigate the presence of seven congeners of polychlorinated biphenyls (PCBs) and (3) to establish correlations between PCBs and leukocytes activity. There were differences in CCL between turtles without FP according to the study area, in BM and BCI between affected and non-affected animals caught in Ubatuba. Were quantified and classified 1033 tumors of 50 green sea turtles, the number of tumors ranged from 1 to 61 and the most part of them was classified in categories of size A (446 tumors) and B (520 tumors) and in anterior region (669 tumors). Was observed difference in PCB 138 concentrations between green sea turtle with and without FP caught in Vitória. Affected animals had higher concentrations of all PCBs quantified, except green sea turtles caught in Vitória in the event of PCBs 118, 138, 153 and 180. Were quantified highest concentrations of PCB 138 and lowest of PCB 180. There were not significant correlations between PCBs concentration and leukocyte activity. The FP has been widely investigate and the studies that aimed to establish correlations between pollutants and animal health are very important, because can contribute for new directions in sea turtle conservation issues.
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Roche, David C. "Trophic Ecology of Green Turtles (Chelonia mydas) From Dry Tortugas National Park, Florida." NSUWorks, 2016. http://nsuworks.nova.edu/occ_stuetd/430.
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Located 100 km west of Key West, Florida, Dry Tortugas National Park (DRTO) is a largely untouched subtropical marine ecosystem that serves as an important developmental habitat, nesting ground, and foraging area for several species of sea turtles, including green turtles. The Park supports a recovering population of green turtles comprised of resident juveniles, subadults, and adults of both sexes; nesting females include residents and migrating females that only return to nest. Stable isotope analysis has been applied widely to describe the trophic ecology of green turtles, from urbanized bays with significant anthropogenic input, to relatively pristine ecosystems with healthy populations at carrying capacity. However, there is a paucity of published literature about the trophic ecology of green turtles in DRTO. This study describes the trophic ecology occupied by two distinct size groups (61 green turtles < 60 cm (SCL) and 98 green turtles > 60 cm (SCL)). Flipper tissue and plasma were analyzed for stable isotopic composition of C and N. Flipper tissue values for δ15N (3.41‰ to 9.69‰) and δ13C (-22.43‰ to -5.38‰) fall within literature values for green turtles, and the wide range of values indicated they could potentially feed at multiple trophic levels. Understanding the trophic ecology of this population of green sea turtles is instrumental to effective management and habitat preservation strategies in DRTO.
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Monteiro, Jessica Correia. "Fibropapillomatosis and the associated Chelonid Herpesvirus 5 in green turtles from West Africa." Bachelor's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2019. http://hdl.handle.net/10400.5/18581.
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Dissertação de Mestrado Integrado em Medicina VeterináriaThe health assessment of free-ranging animals is an increasing concern as more evidence points to the intrinsic link between the environment and animal health. Fibropapillomatosis (FP) is a tumorigenic widespread disease affecting sea turtles, with more incidence among green turtles, Chelonia mydas. Although benign, large FP tumours can impede vital functions, such as feeding, vision and swimming, and impede organ function, leading to death. FP is a multifactorial disease, putatively linked to an infection by the Chelonid herpesvirus 5 (ChHV5) and to degraded habitats. Guinea-Bissau and Mauritania are hotspots for the green turtle in the Eastern Atlantic. Guinea-Bissau hosts the largest rookery for this species in Africa, with strong connectivity with foraging grounds in Mauritania. However, until this date no information was available concerning the prevalence of FP and of ChHV5 in these sites. This study analysed 108 green turtles, captured between 2018 and 2019, for the presence of FP, and used real-time PCR (qPCR) for the detection of ChHV5 DNA in 76 of those individuals. Partial sequences of the ChHV5 UL34 gene were amplified by conventional PCR and sequenced for phylogenetic analysis, including published sequences of ChHV5. The results showed an FP prevalence of 27% (n=32): 36% in Guinea-Bissau and 28% in Mauritania. FP probability decreased with increasing body size and most turtles were only mildly affected. From 28 tumour biopsies analysed, 24 (86%) were positive for ChHV5 DNA, as were 32 (42%) of 76 samples of the normal skin from both FP-afflicted and asymptomatic turtles. The phylogenetic analysis segregated viral variants into four groups: Eastern Pacific, Western Atlantic/Eastern Caribbean, Mid-west Pacific and Atlantic, and sequences from Guinea-Bissau and Mauritania clustered with the Atlantic group. FP prevalence cannot be compared to nearby geographical sites due to lack of information however, when compared with human-disturbed areas it was moderate, which was expected as our study sites have low human impact. Smaller turtles were more susceptible to FP, potentially because larger individuals acquire resistance over time. Detection of ChHV5 in most tumour samples is consistent with its role as aetiological agent of FP, however some asymptomatic turtles were also infected, supporting that other factors are involved in disease expression. We found evidence for recent ChHV5 gene flow along the West coast of Africa, potentially mediated by the migration of infected turtles. This study has established baselines on FP and ChHV5 prevalence for West Africa green turtles, which can be used to assess impacts of anthropogenic activities or climate change in the near future. Systematic monitoring is advisable to assess evolution of disease at these key sites.
RESUMO - FIBROPAPILOMATOSE E O CHELONIA HERPESVÍRUS 5 EM TARTARUGAS-VERDES DE ÁFRICA OCIDENTAL - A avaliação da sanidade de animais selvagens é uma preocupação crescente, à medida que mais evidências apontam para a ligação intrínseca entre o meio ambiente e a saúde animal. A fibropapilomatose (FP) é uma doença neoplásica panzoótica que afeta tartarugas marinhas, principalmente tartarugas-verdes. Embora os tumores sejam benignos, quando atingem dimensões maiores podem impedir funções vitais e levar à morte das tartarugas. A FP está relacionada com a presença de uma infeção pelo Chelonid herpesvirus 5 (ChHV5) e em paralelo com a degradação dos habitats de alimentação das tartarugas. A Guiné-Bissau e a Mauritânia são hotspots para as tartarugas-verdes, sustentando a maior população desta espécie em África, no entanto, até à data, não existia informação científica sobre a prevalência de FP nestas áreas. Este estudo analisou 108 tartarugas-verdes capturadas entre 2018 e 2019 quanto à presença de FP e utilizou a PCR em tempo real (qPCR), após implementação e validação deste método, para detetar a presença do Chelonid Herpesvirus 5 (ChHV5) em 76 desses indivíduos. Fragmentos da glicoproteína B, UL18, UL34 e ADN polimerase também foram amplificados a partir das amostras da Guiné-Bissau e da Mauritânia, por PCR convencional, e sequenciados, para inferência filogenética. Os resultados mostraram uma prevalência de FP de 27% (n=32): 36% em Guiné-Bissau e 28% na Mauritânia. A probabilidade de contrair FP decresce com o aumento do tamanho das tartarugas e a maioria dos animais com FP estavam apenas ligeiramente afetados pela doença. Analisaram-se 28 biópsias de tumores, das quais 24 (86%) foram positivas para o ADN de ChHV5, tal como 32 (42%) das 76 amostras de pele saudável examinadas. A análise filogenética revelou que as sequências virais se separaram em quatro grupos filogeográficos: Pacífico Este, Atlântico Ocidental / Este das Caraíbas, Centro-Oeste do Pacífico, e Atlântico. As sequências da Guiné-Bissau e da Mauritânia agruparam com exemplares do Atlântico. A prevalência de FP foi moderada comparativamente com áreas de maior atividade antropogénica, o que era esperado, dado que os locais de estudo têm baixo impacto humano. As tartarugas mais jovens parecem mais suscetíveis à FP, possivelmente por serem naïves à doença e a adquirem no local de alimentação costeira. A deteção de ChHV5 na maioria das amostras de tumores é consistente com o seu papel como agente etiológico de FP. No entanto, em algumas das tartarugas assintomáticas também se detectou ADN do ChHV5, sugerindo a implicação de outros fatores na expressão da doença. A análise filogeográfica sugere um fluxo genético de ChHV5 ao longo da costa oeste de África, possivelmente mediado pela migração de tartarugas infetadas. Este estudo estabeleceu linhas de base sobre a prevalência de FP e de infeção por ChHV5 para tartarugas-verdes da África Ocidental. Estes dados podem ser usadas para avaliar os impactos da atividade antropogénica e alterações climáticas. É aconselhado a monitorização sistemática desta doença para avaliar a sua evolução nestes locais-chave.
The fieldwork was funded by a grant from the MAVA foundation attributed to the Institute of Biodiversity and Protected Areas from Guinea-Bissau. The investigation was carried out at the Virology Laboratory of Instituto Nacional de Investigação Agrária e Veterinária (INIAV) under the supervision of Doctor Margarida Duarte and Doctor Ana Duarte.
N/A
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Peare, Tigerin. "The conservation genetics of green turtles (Chelonia mydas): Consequences of philopatry and mating behavior /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942476405333.
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Gary, Meagan. "Home Range and Habitat Use of Juvenile Green Turtles in a Shallow Tidal Environment." Thesis, Florida Atlantic University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10610505.
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The home range can be further understood by examining: (1) environmental factors that are responsible for its selection, and (2) habitat use. Green turtle (Chelonia mydas) home ranges are characterized by their food abundance, distribution, and quality. The shallow water habitats of The Bahamas are important foraging sites for juvenile green turtle. The goal of this study was to determine how turtles use their home range at a tidal foraging site. I tracked turtle home range using acoustic telemetry. I conducted esophageal lavage on tracked turtles and mapped the vegetation coverage. Turtle home ranges were small, and often overlapping areas (mean ± SD= 0.64 ± 0.24 km2). Turtles consumed primarily seagrass (Thalassia testudinum), which was concentrated inside the tidal creek. This study documented the smallest recorded home ranges of juvenile green turtles and examines the combination of the effects of tide, temperature, and vegetation on green turtle home range.
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Joseph, Juanita. "Conservation genetics of green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) sea turtles of Southeast Asia." Thesis, Royal Holloway, University of London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436110.
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Borrowman, Kelly. "PREVALENCE AND SEVERITY OF FIBROPAPILLOMATOSIS IN JUVENILE GREEN TURTLES (CHELONIA MYDAS) IN THREE HABITATS ON FLORIDA'S EAS." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4225.
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Fibropapillomatosis (FP) is a tumor-forming disease mainly found in juvenile green turtles (Chelonia mydas) inhabiting Florida's east coast. Despite increased research on the herpes virus that putatively causes it, long-term assessment is still needed of the distribution and severity of FP. Using the decades-long database compiled by the University of Central Florida Marine Turtle Research Group, I determined FP severity and distribution at three different sites: Indian River Lagoon (IRL), Sabellariid Worm Reef (SWR) and Trident Submarine Basin (TSB). Fibropapillomatosis occurred in >50% of IRL turtles, 18% of SWR turtles and <1% of TSB turtles. Regression of FP tumors was correlated with its prevalence, i.e. when and where FP was common, tumor regression was common. The probability of a turtle being non-afflicted or mildly afflicted increased with both increasing straight-line carapace length (SCL) and increasing relative body condition (residuals of log body mass versus log SCL). Mean annual growth rates of IRL and SWR turtles did not vary with FP severity; however, mean annual growth rates in IRL (1.10 cm/y) were significantly higher than in SWR (1.05 cm/y) and TSB (1.04 cm/y). Annual apparent survival estimates for IRL and TSB turtles were 0.72 and 0.73, respectively, and were constant over time. Even with increased prevalence of FP, annual apparent survival estimates were constant and similar to survival estimates of juvenile green turtles in areas without FP. In IRL, survival rates among FP Categories 0, 1 and 2 were similar (0.74, 0.74 and 0.81 respectively) and lower only for FP Category 3 (0.63). Thus, while FP occurred in >50% of turtles in some Florida east coast populations, their annual apparent survival only declined in advanced cases (FP Category 3). These data suggest 1) FP afflicts smaller or younger turtles, 2) larger juveniles, sub-adults and adults are either non-afflicted or possibly recover from this disease, and 3) annual apparent survival rates of green turtle populations are independent of FP prevalence except when tumor growth is extreme.M.S.
Department of Biology
Sciences
Biology MS
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Sanchez, Cheryl. "Sex ratios of juvenile green turtles (Chelonia mydas) in three developmental habitats along the coast of Florida." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5703.
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The concept of temperature dependent sex determination (TSD) has been somewhat of an evolutionary enigma for many decades and has had increased attention with the growing predictions of a changing climate, particularly in species that are already threatened or endangered. TSD taxa of concern include marine turtles, which go through various life stages covering a range of regions. This, in turn, creates difficulties in addressing basic demographic questions. Secondary sex ratios (from life stages post-hatchling) were investigated by capturing juvenile green turtles (Chelonia mydas), 22.6-60.9 cm in straight carapace length (SCL), from three developmental areas along the east coast of Florida (a region known to have important juvenile aggregations) by analyzing circulating testosterone levels. All three aggregations exhibited significant female biases with an overall ratio of 3.2:1 (female: male). The probability of a turtle being female increased as the size of the individual decreased. Ratios obtained in this study were slightly less female-biased, but not significantly different, than those observed in the late 1990s. However, they were significantly more biased than those found in a late 1980s pilot study. The shift to significantly female-biased ratios may be beneficial to a recovering population, an evolutionary adaptation, and is common among juvenile aggregations. A more skewed female bias in smaller size classes may be indicative of recent, warmer periods during incubation on the nesting beaches. This female bias could become more exaggerated if temperatures meet future climate warming predictions.M.S.
Masters
Biology
Sciences
Biology
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Theodossopoulos, Dimitrios. "'What use is the turtle?' : cultural perceptions of land, work, animals and 'ecologists' in a Greek farming community." Thesis, London School of Economics and Political Science (University of London), 1997. http://etheses.lse.ac.uk/2564/.
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This thesis examines the cultural features of landholding and cultivation, as well as perceptions of domestic and wild animals in a community on the island of Zakynthos in southwest Greece. Vassilikos, the community in question, is renowned for its persistent resistance to ecological conservation, as manifested in a ten year long dispute over the local people's right to control parts of their land designated to become a conservation area for the reproduction of Loggerhead sea-turtles. The legislative regulations of turtle conservation allow for the establishment of a marine national park in the area which restrains some inhabitants of Vassilikos from building on their land and engaging in tourism-related enterprises. The particular conservation dispute serves as the common uniting theme of several topics explored in this thesis, all related to the relationship of Vassilikos' people with their physical environment and the animals living in it. In fact, the entire thesis in an attempt to illuminate the cultural matrix behind the local farmers' resistance to ecological conservation. For this reason, the thesis provides a thorough ethnographic analysis of the following six themes: the significance of land ownership for the local farmers, their working relationship with their environment, the relationship between the farmers and their domesticated animals, local attitudes to wild animals, the position and classification of non-human living creatures in Greek Orthodox cosmology, and the passionate involvement of the local farmers with hunting. The thesis concludes by combining the conclusions of these themes to attempt to unravel the pragmatic relationship between the farmers of Vassilikos, their animals and the natural world.
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McMichael, Erin. "Ecology of juvenile green turtles, Chelonia mydas, at a temperate foraging area in the northeastern Gulf of Mexico." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010849.
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Bourjea, Jérôme. "Structure et connectivité de la mégafaune marine à l'échelle d’une région océanique : enjeux pour la gestion durable des tortues vertes dans l'océan Indien occidental." Thesis, La Réunion, 2014. http://www.theses.fr/2014LARE0015/document.
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Ce travail de thèse s'insère dans une démarche globale d'acquisition des connaissances sur la tortue verte (Chelonia mydas) dans l'océan Indien occidental et ce afin de disposer d'éléments scientifiques essentiels à la mise en place d'une gestion cohérente et efficace de cette espèce menacée. Dans un premier temps, appliquant différentes modèles statistiques, ce travail a visé à établir des données de référence sur l'abondance des tortues vertes femelles en reproduction et les tendances sur le long terme des principales populations. Dans un second temps, il a consisté à déterminer la structure génétique et les relations qui existent entre les différentes populations de cette espèce. Enfin, la conservation des tortues marines étant étroitement liée aux pressions extérieures, ce travail a tenté dans un troisième temps de caractériser les pressions anthropiques qu'elles subissent, et notamment celles liées à la pêche. L'ensemble de ces résultats a permis de réaliser des avancées majeures dans la connaissance de la biologie et de l'écologie de la tortue verte et de disposer d'une vision régionale fiable de l'état de conservation de cette espèce dans l'océan Indien occidental. Leur compilation a ainsi permis d'identifier des zones régionales prioritaires de protection mais aussi des sites de vigilance plus spécifiques comme celui d'Europa. Enfin cette synthèse met en lumière les priorités de recherche et les approches scientifiques à favoriser à l'avenir pour améliorer les connaissances et affiner les priorités de conservation non seulement des tortues marines, mais aussi de la mégafaune marine en généralThis thesis is a comprehensive work aiming to improve scientific knowledge on the green turtle (Chelonia mydas) in order to provide key scientific evidences needed for the implementation of coherent and effective management measures to protect at the Western Indian Ocean scale this threatened species. In a first step, this work aimed to established baseline data on the abundance of green turtles nesting females and long term trends of some key nesting populations of the region by applying different modelling methods. In a second step, this work determined the regional genetic structure of this species and the relationships that exists between the different populations. Finally, the conservation of marine turtles being closely dependant to external pressures, this work tried to characterize theanthropogenic pressures they face, more specifically those related to fishing activities. All these results allowed unraveling some key gaps on the biology and ecology of the green turtle in the region and led to a global vision of the conservation status of this species in the Western Indian Ocean. The compilation of the results enabled the identification of regional priority areas for protection, but also some more specific threatened sites such as Europa. Finally, this synthesis shedslight on research priorities and scientific approaches to be promote in the future to unlock other keyscientific issues and refine conservation priorities, not only of marine turtles, but also of marine megafauna as a whole
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Burgett, Claire Margaret. "Green Sea Turtles (Chelonia mydas) in Bermuda Exhibit an Ontogenetic Diet Shift despite Overexploitation of Resources in their Developmental Habitat." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3267.
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Green sea turtles in Bermuda are overgrazing the seagrasses on which later life stages are thought to specialize. I hypothesized that larger green turtles in Bermuda would display individual diet specializations during seagrass scarcity. Stable isotope methods were used to determine the diet composition of green sea turtles from the Bermuda Platform as a function of size class and in turtles captured in successive years. Individual turtles had a wide range of diets, however, the variation in diets was driven by differences among size class rather than within the size classes of larger turtles, indicating that green turtles undergo a dietary ontogenetic shift during their residency on the Bermuda Platform and no clear specialization of diets among late-stage individuals. The apparent lack of dietary specialization of larger turtles indicates that older turtles are not diversifying their diets in response to the drastic reductions in seagrass in Bermuda.
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Anderson, Yvette. "The ecological relationship between the tumor-promoting dinoflagellate, Prorocentrum spp., and fibropapillomatosis in green turtles (Chelonia mydas) in Hawaii and Florida." [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1000101.
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Thesis (M.S.)--University of Florida, 2002.Title from title page of source document. Document formatted into pages; contains xx, 210 p.; also contains graphics. Includes vita. Includes bibliographical references.
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Sterner, Andrew. "Modeling Survival of Immature Loggerheads (Caretta caretta) and Green Turtles (Chelonia mydas) from 10 Years of Mark-Recapture Data at the Florida Power and Light St. Lucie Plant." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5707.
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Loggerheads (Caretta caretta) are listed as Threatened and green turtles (Chelonia mydas) are listed as Endangered under the United States Endangered Species Act. While green turtle nest production in Florida has increased markedly in recent years, loggerhead nest production has followed a more tenuous path. Reasons for these differences are unknown. Limited demographic information is available for these species of conservation concern. I used Barker models, which incorporated mark-recapture, live-resight and dead recovery data, implemented in Program MARK. These models were used to estimate apparent survival for immature loggerhead (<85cm SCL) and green turtle (<60cm SCL) populations foraging in the Atlantic Ocean adjacent to the Florida Power and Light St. Lucie Plant on Hutchinson Island, Florida between 2002 and 2011. My results indicated annual apparent survival was decreasing (from 0.75 to 0.59) for resident immature loggerheads and was stable (~0.81) for resident immature green turtles over the ten year study period. I found that permanent emigration models were better supported than no movement models for both species. Size (straight carapace length) was found to be an important covariate for survival and fidelity parameters in the green turtle analysis but not in the loggerhead analysis. My study is the first to compare survival of two species of immature marine turtles foraging at the same location in the Atlantic. These estimates are also the first available survival estimates for immature marine turtle populations in Florida based on modern mark-recapture techniques, filling a critical knowledge gap. This information is vitally important for managers when evaluating the long-term recovery of these endangered species.M.S.
Masters
Biology
Sciences
Biology
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Kontogiorgi, Elisabeth. "Population exchange in Greek Macedonia : the rural settlement of refugees, 1922-1930 /." Oxford : Clarendon Press, 2006. http://catalogue.bnf.fr/ark:/12148/cb401595634.
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Yasuda, Tohya. "Analytical study on acquisition of ecological information on marine animals for evaluation of a marine protected area : the case study of green turtles in the Andaman Sea." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/135959.
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