<p>This dissertation research explores participatory sea turtle conservation monitoring through a comparison of two case studies, one in North Carolina (NC), USA and the other in Baja California Sur (BCS), Mexico. Participatory approaches in conservation management can supplement state capacity as well as strengthen the involvement of citizens in environmental governance and knowledge production. Despite scholarship challenging the validity of the categories of developing and developed nations, this categorical assumptions derived from this binary world divide continue to inform conservation, and theoretical vocabularies for local roles in conservation management. In developed nations, participatory conservation management is framed through the broader administrative rationalism discourse, and is identified as volunteer conservation or citizen science. In developing nations, participatory conservation management is approached through the discourse of biodiversity and the threats human society poses to it, and is identified through community-based processes of conservation stewardship. The two case studies analyzed in this dissertation serve to interrogate the ways in which these distinct discourses influence outcomes, and consider what may be obscured or overlooked due to discursive constraints. </p><p> Conducting ethnographic research in each case study site, I participated in and observed sea turtle conservation activities and conducted in-depth interviews with relevant sea turtle conservation actors as well as collected documents pertaining to the conservation programs. Sea turtle conservation monitors in NC and BCS perform functionally similar conservation tasks, and I collected data using similar techniques in order to maximize comparability. I compare the case studies, not to generalize to a population, but instead to speak to theoretical propositions and inform existing theory on participatory conservation monitoring. </p><p> Although participatory monitoring in NC and BCS does not result in a democratization of science, there are beneficial outcomes to participants in both places. NC sea turtle monitors are enabled to take ownership of sea turtle stewardship, and BCS sea turtle monitors are enabled to promote conservation and cultural change using the authority of science. These outcomes challenge assumptions about state capacity and local engagements with science in participatory conservation, and the disparate approaches to local roles in conservation in each `world.' The overall findings suggest that a multitude of factors are involved in the production of conservation program frameworks and participant outcomes, and more deeply interrogating the taken for granted assumptions behind conservation designs and implementation can offer stronger understandings of what participatory conservation management can (and cannot) achieve.</p> / Dissertation

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

This mixed methods case study describes an innovative two-semester middle school environmental learning course that departs from traditional Mexican expository pedagogy through the incorporation of experiential and service learning. This research takes place in a small middle school in Pescadero, Baja California Sur, Mexico. The research approach utilized in the study adds to the handful of studies in this cross-disciplinary field by employing quantitative methodologies to measure course outcomes on student environmental knowledge, perceptions, and actions, while simultaneously qualitatively describing the behavioral, educational, environmental, and social experiences of students. This research employs Dewey's theories of experience -- as well as those of more contemporary authenticity theorists -- in order to identify the philosophies that advocate incorporating experiential pedagogy within the curriculum. Implications for Mexican educational policy, practical pedagogical applications, and theory are discussed.

<p>Sea turtles are long lived marine species that are currently endangered because their life history and population dynamics hinder them from withstanding modern anthropogenic threats. Worldwide, fisheries bycatch in on the major threats to the survival of sea turtles and that is also the case in the Eastern Pacific. To establish regional conservation priorities for the mitigation of bycatch, it is essential to first obtain a comprehensive picture of the regional sea turtle bycatch situation. This comprehensive analysis was lacking for the Eastern Pacific; therefore one component of this dissertation (the first chapter) is focused on delivering a regional bycatch analysis for the Eastern Pacific. A literature review was conducted to obtain numbers of turtles captured, frequencies, bycatch and mortality rates per species and country in trawl, longline, and gillnet fisheries, and to compile results of mitigation measures. Moreover, estimates for current annual capture rates in trawl fisheries were obtained and compared with population numbers. </p><p>This regional bycatch used all the information compiled and synthesized to give conservation priorities at the regional level. The review underlines the high bycatch rates in trawls for Costa Rica, Guatemala, and El Salvador and the detrimental impact that these captures could have specially for hawksbill Eretmochelys imbricata due to its reduced population numbers and for green turtle Chelonia mydas due to its highest mortality rate. It also emphasizes the continuous lack of use of TEDs as a bycatch mitigation measure. In longline fisheries, the review identifies the high bycatch rates in pelagic longline fisheries of Costa Rica, Ecuador, and Nicaragua in a global context but given that olive ridley Lepidochelys olivacea is the most common species captured in these countries, it highlights the capture of loggerhead Caretta caretta and leatherback Dermochelys coriacea off Peru and Chile due to their small population numbers. Bottom longlines have high mortality rates compared with pelagic longlines in the region and the review identifies a need for further research in this area due to the scarce information but high mortality rates. The review also noted that some mitigation measures for pelagic longlines like circle hooks and hooks with appendages could bring improvements in the mitigation of bycatch in longline fisheries in the region, there is still considerable work to be done in technology transfer, sea turtle handling, and estimates of post-release mortality rates. </p><p>For gillnet fisheries, the most important highlight is how little information exists for the region given the high rates of bycatch for sea turtles in this gear. However, the difficulties of studying bycatch in highly dynamic and artisanal fisheries are recognized as the major impediment for this situation. Nevertheless, the high bycatch rates in areas where sea turtles congregate in high numbers like in foraging grounds for loggerhead in Baja California, Mexico and for greens in Paracas and Sechura, Peru, calls for either gear modifications (which has not been that successful), change of gear, or areas closed for gillnets. </p><p>The second half of the dissertation is focused on foraging ecology of oceanic sea turtles in the Southeast Pacific Ocean. Sea turtles in the oceanic stage are the least known stage due to the difficulty of accessing these individuals. However, it is a very important stage in the life cycle and can be critical for the population dynamics of sea turtles as some population models have shown. Therefore, this dissertation is filling a gap in the life cycle of sea turtle populations in the Eastern Pacific. </p><p>To study foraging ecology, we used Stable Isotope Analysis (SIA) of turtle tissues as well as potential prey items from the oceanic realm. SIA is a great tool because it gives an integrated view, from days to weeks, of prey from a consumer tissue. SIA also can be used to link consumers to habitats when elements that have spatial trends are used. In chapter two, we investigate the foraging ecology of three species of sea turtles to compare trophic status and to observe if spatial patterns were shown in the SIA signatures of sea turtles. To our knowledge this is the first study employing SIA to research the ecology of three species of sea turtles from the same time and space. Our results show that spatial patterns in delta15N and delta13C were observed in sea turtle's tissues as correlations with latitude. We also found that loggerhead's signatures differed significantly from green and olive ridleys, especially in terms of delta15N. Loggerheads had higher values of delta15N and also a wider nitrogen trophic niche. Greens and olive ridleys were similar in isotopic nitrogen values but they were significantly different in carbon. When analyzing a smaller group of animals captured in a more restricted area, nitrogen differences were not found which suggests that latitudinal spatial patterns play an important role in the nitrogen signature. On the contrary, carbon signatures still differed among turtles in the restricted area which suggest that the inshore-offshore trend is strong and made us conclude that loggerheads are restricted to oceanic areas but that greens and olive ridleys could be using both coastal and oceanic areas.</p><p>In chapter three, we conduct a mixing model analysis using the Bayesian program SIAR to identify the most important prey items for green, olive ridley, and loggerhead off Peru. Also, we wanted to identify the contribution of longline baits in the diet of oceanic turtles. The analysis was restricted to the central zone of our study area to avoid spatial trends in nitrogen. To use as sources in the model, we collected potential prey items offshore Peru during trips on longline fishing vessels and obtained their stable isotope signatures. Results from our mixing models show that for greens and olive ridleys, crustaceans, mollusks, and coastal Ulva (indicator of coastal prey) were the only important food items. In the case of greens, crustaceans had a very high proportional contribution and due to the fact that nitrogen values of crustaceans were the lowest ones among the sources it seems that greens would be eating in a lower trophic level. The importance of coastal Ulva for greens and olive ridleys is a confirmation of our findings from chapter two where we suggest that these two species could be using oceanic as well as coastal areas. </p><p>Results for loggerheads showed cnidarians, mollusks, mackerel and squid bait as foraging items and highlights the differences among this species and the other two. The lack of importance of coastal Ulva again suggests that loggerheads remain only in oceanic areas off Peru. Moreover, the importance of mackerel and squid, the most common longline baits, suggests this species is the one interacting the most with longline fisheries and that cumulative effect of multiple interactions could have a detrimental effect in this population.</p> / Dissertation

Effective population management of green sea turtles (Chelonia mydas) necessitates understanding the temporal variation in foraging grounds used in ontogenetic stages, and the effect that the assimilated diet within those habitats has on nutritional gain, growth and eventual reproductive output. Texas coastal waters provide foraging grounds critical to meeting the nutritional needs of green turtles during early life history. To characterize temporal shifts in foraging strategy stomach contents combined with stable carbon (delta13C) and nitrogen (delta15N) isotopes of scute tissue were examined across size classes of stranded juvenile green turtles from the middle and lower Texas coast during 2007-2010. Findings from dietary analysis generally corroborated those from stable isotopes in scute samples. Results indicate green sea turtles exhibit multiple shifts in diet and habitat along the Texas coast. Although isotope values in the tissues of some <25 cm SCL turtles signified recent recruitment to jetty habitat, most in this size class exhibited depleted delta13C and enriched delta15N values indicative of oceanic life. Reinforcing oceanic occupancy from stable isotope results was forage material dominated by oceanic items such as Sargassum spp., Scyphozoa spp., and plastic debris. Diet analysis of 25-34.9 cm SCL turtles implied regional differences existed in macroalgae and seagrass consumption. Enriched delta13C and delta15N values in newest scute suggest most turtles inhabited the jetty environment, where macroalgae is the most available forage. A definitive shift by >35 cm SCL turtles to inshore seagrass habitat was revealed by a diet of seagrasses and tissue enriched in delta13C and depleted in delta15N. This is the first study to integrate stomach contents of several green turtle size classes with tissue analysis of stable isotopes. The combination of these techniques provided an assessment of the effectiveness of stable isotope analyses in documenting diet and habitat shifts. Stomach content examination determined the most recent diet consumed within the habitat occupied, whereas stable isotope analysis provided a time-integrated synopsis of diet and habitat shifts. Findings indicate integration of stomach content and stable isotope analysis is highly effective for characterizing habitat use and foraging strategy of ontogenetic-stage green sea turtles.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-02-12T17:34:13Z No. of bitstreams: 1 robsonhenriquedecarvalho.pdf: 3308952 bytes, checksum: 15b338c6950df1516539e069a54dbee2 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-02-26T12:21:34Z (GMT) No. of bitstreams: 1 robsonhenriquedecarvalho.pdf: 3308952 bytes, checksum: 15b338c6950df1516539e069a54dbee2 (MD5) / Made available in DSpace on 2016-02-26T12:21:34Z (GMT). No. of bitstreams: 1 robsonhenriquedecarvalho.pdf: 3308952 bytes, checksum: 15b338c6950df1516539e069a54dbee2 (MD5) Previous issue date: 2014-02-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A costa brasileira é área prioritária para conservação das tartarugas marinhas, pois cinco das setes espécies de tartarugas existentes no mundo podem ser encontradas no Brasil, estando todas ameaçadas de extinção. As ameaças para esses animais incluem: Ocupação da costa, poluição, doenças e principalmente capturas incidentais em artefatos de pesca. Resgatar a sabedoria popular de pescadores e o conhecimento local é essencial para a conservação desses quelônios. O Objetivo desse trabalho foi apresentar e comparar o conhecimento de pescadores sobre tartarugas de três cidades do sul do Espírito Santo. O estudo foi realizado nas cidades de Anchieta, Piúma e Guarapari, ES, Brasil. As informações relacionadas ao conhecimento local e interação entre as pessoas e tartarugas marinhas foram coletadas através de entrevistas utilizando questionário semiestruturado. Foram entrevistados 44 pescadores e 7 marisqueiras, sendo 19 pescadores em Piúma, 5 pescadores e 7 marisqueiras em Guarapari e 20 pescadores em Anchieta. A tartaruga-de-couro é mais conhecida em Piúma e a verde a mais conhecida em Anchieta e Guarapari. As características que permitem diferenciar os animais são formas do casco e cor e os animais são conhecidos por vários nomes populares. Em Piúma e Anchieta foram citadas altas taxas de captura em rede e consumo de carne de tartaruga. As atitudes em relação as tartarugas marinhas e o conhecimento sobre a reprodução desses animais são diferentes em cada cidade devido a fatores como: Cidade que reside e arte de pesca. Os resultados desse estudo indicam que a conservação de quelônios marinhos requer conhecimento das práticas diárias de comunidades locais e as peculiaridades envolvidas na relação entre os pescadores e as tartarugas marinhas, além do levantamento dos impactos causados pelas práticas diárias. / The Brazilian coast is a priority for conservation of sea turtles, because five of the seven species in the world and they can be found in Brazil and all of them are endangered. The threats to this animal include: Occupancy of the coast, pollution, disease and mostly incidental catches in fishing artifacts. Rescue the folk wisdom of fishermen and local knowledge is essential to the conservation of these turtles. The aim of this present study was to show and compare the knowledge of fishermen on turtles from three cities in southern of Espírito Santo. The study was conducted in the cities of Anchieta, Piuma and Guarapari, ES, Brazil. The information related to local knowledge and interaction between people and sea turtles were collected through interviews using a semistructured questionnaire. Forty-four fishermen and seven seafood were interviewed, where nineteen were fishermen on Piuma, five fishermen and seven seafood in Guarapari and twenty fishermen in Anchieta. The leatherback turtle is best known in Piúma and the Green one is best known in Anchieta and Guarapari. The characteristics to differentiate these animals are shell shape and color and they are known by several common names. In Piuma and Anchieta were cited high rates of capture on fishing net and consumption of turtle meat. Attitudes and knowledge about reproduction is different in each city due to factors such as location and fishing gear. The results of this study indicate that the conservation of marine turtles requires knowledge of the practices of local communities and the peculiarities involved in the relationship between fishermen and turtles, and a survey of impacts caused by everyday practices.

A beach conservation programme protecting nesting loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles in South Africa was started in 1963. As initial numbers of nesting females were low for both species (107 loggerheads and 24 leatherbacks) it was proposed that the protection of eggs, hatchlings and nesting females along the nesting beach would induce population growth and prohibit local extinction. Today, 50 years later, the loggerhead population exceeds 650 females per annum, whereas the leatherback population counts about 65 nesting females per year. The trend for leatherback turtles is that the population has been stable for about 30 years whereas loggerheads are increasing exponentially. Thus, this thesis investigated several life-history traits to explain the differing responses to the ongoing beach conservation programme. Reproductive output and success were assessed for both species; it was hypothesised that environmental conditions are sub-optimal for leatherback turtles to reproduce successfully. It was ascertained that nesting loggerhead females deposit larger clutches than leatherbacks (112 ± SD 20 eggs and 100 ± SD 23 eggs, respectively), but that annual reproductive output per individual leatherback female exceeds that of loggerhead turtles (±700 eggs and ±448 eggs, respectively) because they exhibit a higher intra-seasonal nesting frequency (leatherbacks n = 7 and loggerheads n = 4 from Nel et al. 2013). Emergence success (i.e. the percentage of hatchlings produced) per nest was similar for both species (loggerhead 73.6 ± SD 27.68 % and leatherback turtles 73.8 ± SD 22.70 %), but as loggerhead turtles nest in greater numbers, i.e. producing more hatchlings per year, the absolute population growth potential favours the loggerhead turtle. The second factor investigated was sex ratio because sea turtles display temperature-dependent sex determination (TSD) where extreme incubation temperatures can skew the sex ratio (i.e. feminising or masculinising a clutch). It was suspected that leatherback turtles are male-biased as this is the southern-most rookery (for both species). Further, leatherback nests are generally closer to the high tide mark, which might induce a cooling effect. Standard histological techniques were applied to sex hatchlings and a generalized linear model (GLM) was used to approximate annual sex ratio. Loggerhead sex ratio (2009 - 2011) was estimated at 86.9 ± SE 0.35 % female-biased; however, sufficient replication for the leatherback population was only obtained for season 2010, which indicated a 97.1 % (95 % CI 93.3 - 98.7) female bias. Both species are, thus, highly female-biased, and current sex ratio for leatherback turtles is not prohibiting population growth. Current sex ratios, however, are not necessarily indicative of sex ratios in the past which would have induced present population growth. Thus, to account for present population growth profiles, sex ratios from the past needed to be ascertained. Annual sex ratios (1997 - 2011) were modelled from historical air and sea surface temperatures (SSTs) but no significant change over time was obtained for either loggerhead or leatherback turtles (linear regression; p ≥ 0.45). The average sex ratio over this 15-year period for the South African loggerhead turtle was approximated at 77.1 ± SE 3.36 % female-biased, whereas leatherbacks exhibited a 99.5 ± SE 0.24 % female bias. Re-analysing data from the mid-80s by Maxwell et al. (1988) also indicated a 77.4 % female bias for the South African loggerhead population. It is, therefore, highly likely that sex ratios of the South African loggerhead and leatherback sea turtle populations have been stable for at least three decades and are not accountable for the differing population growth profiles as they are displayed today. Another possibility that could explain the opposed population growth profiles is the time taken for animals to replace themselves, i.e. age at maturity. It was suspected that age at maturity for the South African loggerhead turtle is comparable with that for leatherbacks. Using data from a 30-year mutilation tagging experiment (i.e. notching), age at first reproduction for South African loggerhead females was estimated. Results ranged broadly but a mean of 36.2 ± SD 7.71 years was obtained using a Gaussian distribution. Age at reproduction of the South African leatherback turtle was not determined but the literature suggests a much younger age of 13.3 - 26.8 years (Zug & Parham 1996, Dutton et al. 2005, Avens et al. 2009, Jones et al. 2011). Therefore, population growth would favour leatherback turtles as they exhibit a much shorter generation time. Finally, it was concluded that all life-history parameters investigated favour leatherback turtles, yet loggerheads are displaying population growth. However, as there were no obvious constraints to population growth on the nesting beach, it is suspected that population growth of the South African leatherback turtle is either unobserved (due to inadequate monitoring not capturing sufficient numbers of nesting events to establish a trend) or that population growth is prohibited by some offshore factor such as industrial fisheries (or some other driver not yet identified). Monitoring should, thus, be expanded and offshore mortality monitored as the leatherback population nesting in South Africa is still critically endangered with nesting numbers dangerously low.

Loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles as well as their eggs and hatchlings have been protected on their nesting beach in South Africa (SA) since 1963. Both nesting populations were expected to show similar trends in recovery following the application of identical protection and conservation measures. The loggerhead nesting population has responded favourably to these protection efforts. In contrast, the leatherback nesting population showed an initial increase but is currently stable. The reason for this difference in response is thought to be due to differential offshore mortality of these two species. This prompted an investigation into the different sources of sea turtle mortality in the South Western Indian Ocean (SWIO). Specific aims were to identify and quantify sources of loggerhead and leatherback mortality on nesting beaches as well as in the oceans. Reasonable survivorship at all age classes is important to ensure recruitment of new nesting individuals into sea turtle populations. Mortality of nests, eggs per nest and hatchlings were quantified over two seasons for the loggerheads and leatherbacks nesting in SA. The beach was patrolled on foot to encounter and record females emerging from the ocean and later, hatchlings from their nests. The nests were then monitored during the incubation period and excavated once hatched. The fates of 925 nests were determined during these two nesting seasons (2009/2010 and 2010/2011). The main source of loggerhead and leatherback nest destruction was predation (8.6 percent and 15.7 percent respectively) followed by nest erosion (2.2 percent and 6.3 percent respectively). Overall nest success was high but higher for loggerheads (89 percent) than for leatherbacks (78 percent). The main cause of egg mortality for both species was early developmental arrest, followed by predation by ants and ghost crabs. Hatchlings en route to the sea were almost exclusively predated by ghost crabs (4.2 percent of emerged loggerhead hatchlings and 3.2 percent of emerged leatherback hatchlings). It appears that both species benefit from the coastal conservation efforts. When sea turtles leave the nesting beach, either as hatchlings or adults, conservation and monitoring becomes more difficult and sea turtles are exposed to a multitude of threats, including anthropogenic threats. Age classes tend to be spatially separated due to different habitat and dietary requirements. The type of threat sea turtles are exposed to thus depends on the current age class. Offshore sources of mortality in the SWIO were identified and where possible loggerhead and leatherback mortality was quantified and mapped spatially. Loggerheads were mostly exposed to and had the highest mortality in the artisanal fisheries in the SWIO (> 1000 per annum), inshore trawling (ca. 41 per annum), shark nets (protective gill nets) (21.6 ± 6.7 per annum) and the pelagic longline fishery (5.0 ± 4.4 per annum). In contrast, leatherbacks with a pelagic lifestyle, were mostly exposed to pelagic longline fisheries (7.8 ± 7.8 per annum). A spatial analysis of fishing activities indicated that leatherback home ranges overlapped 41percent with pelagic longline fishing activity in the SA EEZ, whereas the overlap between pelagic longliners and loggerhead home ranges was 29 percent. The quantified sources of mortality provide some explanation for the trend in the loggerhead nesting population but not the trend in the leatherback nesting population. Hatchling survivorship to adulthood was estimated to determine the viability of the two nesting populations as well as to determine whether offshore mortality was responsible for the difference in recovery of the two populations. Loggerhead hatchling survivorship to adulthood was estimated at between 2 and 10 per 1000 hatchlings, the minimum requirement for an increasing population. The adopted sophisticated model shows that leatherbacks have a survival rate of 5 to 10 per 1 000 hatchlings. However, this suggests that the population is increasing, but the leatherback population is stable. Perhaps the age to maturity of SA leatherbacks is greater than 12 years, or fisheries-related mortality affects younger age classes than initially thought. It is therefore recommended that the turtle monitoring area is extended to include other potential nesting grounds. In addition, observer or monitoring programs for commercial as well as artisanal fisheries needs to be extended throughout the SWIO to quantify sea turtle mortality. Ultimately a comprehensive multi-regional approach is required for the conservation of these highly migratory species.

Stable isotope analysis is a powerful tool that can be used to describe a population’s foraging niche by identifying basal resource use, trophic feeding levels, environmental stability, seasonal ecological variation, important shifts in life history, ontogenetic shifts, intraspecific habitat use, and population dynamics. Describing these relationships in endangered marine turtle populations and their critical foraging grounds is essential for determining informed management decisions. This study systematically describes the foraging niche of hawksbills Eretmochelys imbricata, and green turtles, Chelonia mydas in Buck Island Reef National Monument, U.S. Virgin Islands, a critical habitat for nesting and foraging. It assesses the relationships within and between the species in terms of overlap, annual and seasonal variation, and life history and feeding strategies within the community. Most importantly it describes these relationships with metrics that can be used in global comparisons or to measure change in local conditions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

<p>Colonization by bacteria and fungi has been shown to reduce hatching success of sea turtle nests. Presence of microbial pathogens is commonly associated with egg failure, and in some species, it has even been shown to cause up to 90% nest mortality. Developing sea turtle embryos can only rely on non-specific defenses, such as the eggshell and the proteins present in the egg albumen. For a long time, it has been suggested that the fluid in which the eggs are coated during oviposition may contain antimicrobial properties that might protect eggs against potential pathogens that are found in the egg chamber. This study aimed to evaluate the antimicrobial properties of the cloacal fluid of loggerhead sea turtles. Cloacal fluid samples were collected at the Wassaw National Wildlife Refuge, Georgia during the 2021 nesting season (June-July). Protein fractionation of the samples was carried out using commercially available ultracentrifugation devices of 3K, 10K and 30K molecular cut-off weights. A microplate-based turbidimetric growth inhibition assay recorded the antimicrobial activity of the peptide fractions and the crude extract. We found that the cloacal fluid of loggerheads has antimicrobial properties against <i>Serratia marcescens</i> and <i>Morganella morganii</i>, and some mild action against <i>Pseudomonas aeruginosa</i>. Results obtained from the microplate-based turbidimetric assay were confirmed by assessing viability of cells upon 24 hours of exposure to the fluid. Furthermore, this study found that the cloacal fluid contains proteins with molecular weight ranging from approximately 5 to 250 kDa, and that proteins with higher molecular weights (MW>30kDa) are found in greater abundance. Further studies are needed to understand the mechanism of action of the proteins and peptides present in the cloacal fluid to potentially develop antimicrobial compounds that can be used to increase hatching success globally.</p>