Migration is a widespread and complex phenomenon in nature that has fascinated humans for centuries. Connectivity among populations influences their demographics, genetic structure and response to environmental change. Here, I used the loggerhead turtle (Caretta caretta, L.) as a study organism to address questions related to migratory connectivity and carry-over effects using satellite telemetry, stable isotope analysis and GIS interpolation methods. Telemetry identified foraging areas previously overlooked for loggerheads nesting in Florida. Next, I validated and evaluated the efficacy of intrinsic markers as a complementary and low cost tool to assign loggerhead foraging regions in the Northwest Atlantic Ocean (NWA), using both a spatially implicit and spatially explicit (isoscapes) approach. I then focused on the nesting beaches and developed a common currency for isotopic studies based on unhatched eggs, which provide a non-invasive and non-destructive method for more extensive sampling to elucidate isotopic patterns across broader spatiotemporal scales. Lastly, I found that intra-population variations in foraging strategies affect annual and long-term reproductive output of loggerheads nesting in Florida. Understanding geospatial linkages is critical to the fostering of appropriate management and conservation strategies for migratory species. My multi-faceted approach contributes to the growing body of literature exploring migratory connectivity and carry-over effects.

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.

Changes in abundance of interactive species can have cascading, community-wide effects (Soule et al. 2003). Raccoons (Procyon lotor) prey on a competitor for marine turtle eggs, the Atlantic ghost crab (Ocypode quadrata). Conservation of marine turtles often includes managing raccoons-the most obvious egg predator-which may have broader ecological effects, and unknown effects on egg predation. Neither the relationship between raccoons and ghost crab density nor the effects of ghost crab density on egg predation are well understood. I studied raccoon-ghost crab interactions and the effects of environmental variation on their activity during the 2007 marine turtle nesting season on Canaveral National Seashore, FL. My goal was to model predator activity and identify efficient management strategies to reduce egg predation. Raccoon activity increased with increasing habitat diversity and edge of the dominant cover type, coastal strand. Raccoon activity increased locally and became less variable near segments of beach accessed for human recreation, but activity was greater on undeveloped beach, where habitat diversity and edge were greater. Ghost crab density and size were primarily affected by sand characteristics and recreation but decreased with increasing raccoon activity in June, which may have contributed to sustained declines in ghost crab density. Hatching success of marine turtles decreased with increasing ghost crab egg predation, suggesting ghost crabs are an important cause of egg mortality and not merely scavengers on unhatched eggs. Egg predation by ghost crabs was unrelated to ghost crab density or size, likely a result of monitoring limitations, but raccoon activity increased with increasing egg predation by ghost crabs, supporting previous research and experimental evidence suggesting ghost crabs can facilitate secondary nest predation by raccoons. This indirect interaction has strong implications for marine turtle conservation, because its strength may increase with increasing ghost crab density, potentially negating the effects of raccoon removal.

No description available.

Little is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles could detect. Second, I used food to train older turtles to swim toward one light color, and then to discriminate between the rewarded light and another light color ; lights were presented at intensities equally above the phototaxis threshold. Lastly, I varied light intensity so that brightness could not be used as a discrimination cue. Six turtles completed this task and showed a clear ability to select a rewarded over a non-rewarded color, regardless of stimulus intensity. Turtles most rapidly learned to associate shorter wavelengths (blue) with food. My results clearly show loggerheads have color vision. Further investigation is required to determine how marine turtles exploit this capability. / by Morgan Young. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

Worldwide, sea turtles are especially vulnerable immediately after emerging from nests. Many monitoring programs measure hatchling production from nest inventories. These inventories rarely account for mortality occurring post-emergence, leaving an incomplete estimate of hatchling production. This study addresses the nest-to-surf data gap for Florida’s east coast nesting assemblages of loggerhead sea turtles (Caretta caretta). Five locations were surveyed during the 2016 nesting season by using infrared time-lapse imagery, night vision optics, and track maps. Over all beaches, 7.6% of the observed hatchlings did not survive to reach the water. Mortality sources varied by location. Observed predators included: foxes, bobcats, yellow-crowned night herons, ghost crabs, and gulls. Hatchling disorientation and misorientation occurred more frequently in urban areas than natural areas. Factors including number of hatchlings emerging, nest-to-surf distance, and urbanization may help managers estimate nest-to-surf mortality. This study will improve life history models that serve as foundations of conservation management. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

The research presented in this study has been conducted in an effort to aid in the creation of a biomimetic shell that may be employed in full-scale field experiments to determine the efficacy of mitigation options to limit loggerhead mortality in boat strike incidents. The objectives of this research include the development of experimental testing procedures for the material characterization of the loggerhead carapace, and the design, fabrication, and evaluation of an artificial prototype carapace. A photographic database of wounded sea turtles in Georgia was evaluated in order to determine the primary sources of loggerhead collision injuries and the most common regions of the carapace damaged in boat strike incidents. Skeg impact was found to be the most common source of injury, with a frequency of 44%. In addition, 74% of the sea turtles reviewed sustained injuries to the center third of their carapace length, indicating this region as the most probable impact location. Material testing procedures were developed for evaluating the material properties of the loggerhead carapace. This was followed by the material testing of three loggerhead shells for the purpose of determining localized mechanical properties. Samples were harvested from the shells in a manner designed to identify potential variations in properties due the location and orientation of the coupons within the carapace. Each coupon was subjected to axial tension or three-point bending. Specialized tabs were designed for tension testing in order to accommodate the coupon's irregular geometry and minimize curvature-induced moments. The tensile test results indicated that the longitudinal and transverse properties of the loggerhead carapace were similar. The tensile strength, elongation at failure, and modulus of elasticity were determined to have percent variations of 12.2%, 10.7%, and 10.1% respectively. In contrast, the three-point bending test results indicated that the modulus of rupture and flexural modulus for the transverse samples were approximately four times greater than those of the longitudinal samples. This variation may be attributed to regions of weak tissue running transversely through the carapace. The results of the material testing were utilized in the design of two prototype composite shells. The prototypes were successful in simulating the strain at failure and force per unit width to within 10% of the loggerhead carapace. The resulting procedure may be used to create artificial shells suitable for prototype scale tests in natural environments. In addition, the material testing methods developed for this investigation may offer insight into procedures for evaluating alternate forms of rigid or curved biological specimens.

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No. of bitstreams: 0 Previous issue date: 2017-02-21 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Os filhotes e juvenis de quelônios não apresentam anatomicamente características sexuais secundárias visíveis, não sendo possível diferenciar o sexo através da observação da carapaça. Vários autores defendem a análise histológica como a melhor técnica para se realizar a sexagem de filhotes da espécie Caretta caretta. Os objetivos do presente trabalho foram realizar a identificação sexual de filhotes de C. caretta através da morfometria geométrica da carapaça e plastrão e da histomorfologia, além de verificar se há diferença entre as populações dos estados do Espírito Santo e da Bahia com base na morfometria geométrica da carapaça e plastrão. Foram utilizados 204 filhotes natimortos, coletados em diversos ninhos ao longo da praia de Sítio do Conde, Conde, Bahia, e de Regência Augusta, Linhares, Espírito Santo, ambas localizadas no Brasil. Para a análise morfométrica, cada animal teve a carapaça e o plastrão fotografados e os softwares TPSUtil, TPSDig2 e MorphoJ foram utilizados para a realização das análises pertinentes. Posicionados em decúbito dorsal, os espécimes foram ressecados e o plastrão e vísceras foram removidos para permitir a visualização das gônadas e rins, que depois de fotografados foram armazenados em formalina 10% tamponada. Posteriormente foram submetidos à técnica histológica convencional. Verificou-se uma razão sexual favorável às fêmeas. A análise de componentes principais não apontou diferença na carapaça e plastrão de machos e fêmeas das duas localidades. Apenas a análise de função discriminante revelou que há diferença entre a carapaça e plastrão dos espécimes das diferentes localidades. As gônadas estavam localizadas próximas ao hilo renal, com formato filiforme. Nos ovários foi possível observar o córtex constituído por epitélio cúbico simples ou estratificado bem desenvolvido envolvendo a medula desorganizada e rica em matriz intersticial. O córtex dos testículos era composto por um epitélio pavimentoso simples, medula muito bem desenvolvida e com pouca matriz intersticial, observando-se vários túbulos seminíferos. Trabalhos realizados com filhotes de tartaruga cabeçuda e outras espécies de quelônios, utilizando a morfometria geométrica, também demonstraram haver diferenças na carapaça e no plastrão que distinguem o sexo de filhotes recém nascidos. As características histológicas identificadas foram semelhantes às encontradas por outros autores. Outros trabalhos defendem que a análise macroscópica é suficiente para identificar o sexo de filhotes de tartarugas, o que foi demonstrado efetivamente para Dermochelys coriacea e Chelonia mydas, mas não foi efetivo para C. caretta. A morfometria geométrica se mostrou uma ferramenta promissora cuja análise pôde, conforme nosso estudo, corroborar a existência de duas sub-populações que ocorrem no litoral brasileiro. / The hatchlings and juvenile turtles have not anatomically visible secondary sex characteristics, so it is not possible to differentiate sex by viewing the carapace. Several authors advocate histological analysis as the best technique for performing sex of the Caretta caretta’ hatchlings. The aims of this study were to identify sex of hatchling C. caretta by geometric morphometrics of carapace and plastron and histomorphology and analyze if are difference between populations from Espirito Santo and Bahia by geometric morphometric of carapace and plastron. 204 stillborn hatchlings were collected in different nests along the Sítio do Conde’ Beach, Conde, Bahia and Regência Augusta’ Beach, Espirito Santo, both located in Brazil. For morphometric analysis each animal had photographed the shell and plaston and we used the software TPSUtil, TPSDig2, and MorphoJ for morphometrics analysis. The specimens were positioned and removed the plastron and some viscera to allow visualization of the kidneys and gonads, photographed after they were stored in 10% buffered formalin. The histological analysis followed the steps of conventional histological technique. Principal Components Analyzes do not reveals difference in carapace and plastron between females and males. Just discriminant function reveals there are differences between two localities. The sex ratio was female bias in both localities. The gonads were located near the renal hilum, with threadlike format. Ovarian cortex was possible to observe a welldeveloped cuboidal epithelium, associated with a disorganized medulla and interstitialrich matrix. The cortex of the testes was composed of a thin layer of simple squamous epithelium, a very well-developed medulla and low interstitial matrix, observing several seminiferous tubules clearly distinguishable. Work done with hatchling loggerhead turtles and other species also showed significant differences in the carapace that distinguish the sex of young turtles. The histological features were similar to those identified by other authors, some argue that the macroscopic analysis is sufficient to identify the sex of hatchlings, which has been shown to effectively Dermochelys coriacea and Chelonia mydas, but was not effective in C. caretta. Hormonal measurements were also satisfactory to sex in order to young C. mydas, but authors disagree on this method to other species. Geometric morphometrics proved to be a promising tool whose analysis could, according to our study, corroborate the existence of two subpopulations that occur in the Brazilian coast.

The beaches of Broward County, Florida are a prevalent nesting site for loggerhead (Caretta caretta) sea turtles, however extensive beach erosion is threatening critical nesting habitat. Beach renourishment, the process of transporting offshore or upland sediment onshore, is a widely used method of replenishing lost sand. However, renourishment can negatively affect sea turtle nesting habitat by increasing beach compaction; the resistance to applied pressure in pounds per square inch (psi). Increased sand compaction impedes the digging of the female which affects nesting success. The influence of beach compaction on sea turtle nesting patterns has never been previously examined over the course of a nesting season on Hillsboro and Deerfield Beach. Therefore, this study was designed to examine beach compaction data for Hillsboro, a mostly natural beach, and Deerfield, a completely renourished beach, during the 2010 nesting season and analyze the compaction data against 2010 nest and false crawl (FC, non-nesting emergence) data. Compaction readings were collected during every other week March-October using a soil compaction meter at every other street address along three beach positions, the dune base, mid-beach, and average high tide line (HTL); and at three depths, 15 cm, 30 cm, and 45 cm. Values were not statistically different throughout the season for each beach, so seasonal mean compaction values were used for each beach position and depth. Hillsboro compaction values were rarely over 500 psi (35 kg/cm2), even at 45 cm depth. Deerfield compaction values exceeded the 600 psi (42kg/cm2) measurement limit of the meter in approximately 60% of the compaction values at 30 cm or 45 cm depth. Sand compaction data was analyzed for any trends between beaches as well as within each beach. Historical data shows higher loggerhead nesting success, the number of nests/total number of crawls (including FC) x 100, on Hillsboro Beach than on Deerfield Beach. The average beach compaction values were compared to nesting success and to nest and FC density within each station area. There was a significant inverse relationship (p<0.05) between beach compaction and nesting success at each of the beach positions and depths, when both Hillsboro and Deerfield Beaches were analyzed together, except at the Mid 30 cm and Dune 45 cm depth. The strongest relationship for the combined beaches was at the HTL 15 cm depth (R2=0.3821, p<0.001). When Hillsboro was analyzed alone, beach compaction and nesting success was only significantly inversely related (R2=0.0875, p<0.02) at the HTL 15 cm depth. This demonstrates that while increased beach compaction may partially influence nesting success, there are likely other beach characteristics that contribute to nest site selection of loggerheads in Northern Broward County. The inverse relationship between Hillsboro mean beach compaction and nest density (nests per meter) was significant only at the HTL 15cm depth (p<0.002) and the inverse relationship between mean beach compaction and false crawl density (FC per meter) in Hillsboro was only significant at the Dune 15 cm (p<0.019) and the Dune 30 cm (p<0.038) depths. Although, increased beach compaction was expected to relate to higher FC density, FC density showed a significant inverse relationship to mean beach compaction at all Deerfield Beach positions and depths in and this suggests off-shore factors may be affecting nest site selection.

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.