Loggerhead turtle (Caretta caretta) eggs were collected at the time of laying during the summer of 1977 on the beaches of Canaveral National Seashore and the Merritt Island National Wildlife Refuge in Brevard County, Florida. The eggs were placed in land-lines buckets and maintained at ambient temperature in a house trailer hatchery. After 50 to 55 days of incubation whole or partial clutches were transferred to glass observation containers and covered to a depth of 20 cm. Hatching and emergence behavior were visually observed and activity was timed on an event recorder that was activated by four motion switches placed within or above the clutch. Pipping of the eggs occurred at a mean of 60.5 days after egg deposition. Emergence occurred at a mean of 61.8 hours after pipping and 63.1 days after egg deposition. The hatching and emergence sequence was described. It was concluded that hatching and emergence were socially facilitated. A mechanism for socially facilitated hatching was proposed. Volumetric reduction of the nest behavior before or during pipping was described. Emergence may be inhibited by rising temperatures in the morning and stimulated by falling temperatures within a certain range at night. Social facilitation, in addition to the obvious value of providing a means for reaching the surface, was apparently advantageous to hatchlings as they emerged and raced towards the surf en masse. Under these conditions predators are likely to be efficient than they would be if hatchlings emerged singly.

Insight into blood values for free-ranging populations of chelonians is very incomplete. A better understanding of marine turtle ecological physiology is necessary for population health assessments and conservation management plans. Vitamins A and E are fat-soluble compounds required by vertebrates. Vitamin A is required for growth, differentiation and integrity of epithelial tissue, bone remodeling, reproduction and vision. Vitamin E is a constituent of cell membranes where it is an antioxidant and free radical scavenger. Both nutrients are required for reproduction and immune system function. I determined concentrations of vitamins A and E in plasma of blood samples from Caretta caretta and Chelonia mydas using high performance liquid chromatography (HPLC). The first investigation focused on vitamin concentrations in nesting Caretta caretta and Chelonia mydas in the Archie Carr National Wildlife Refuge, Melbourne Beach, Florida, USA. Vitamin A concentrations were significantly higher in the herbivore, Chelonia than in the carnivore, Caretta. Plasma vitamin A concentrations decreased in Caretta as the nesting season progressed, while they remained constant in Chelonia. Plasma vitamin A concentrations only decline after liver stores of the vitamin are depleted, so it appears Caretta did not feed during the nesting season. Plasma vitamin concentrations in Chelonia remained stable during the nesting season, so it is not clear whether green turtles fed or fasted as the season progressed. Plasma vitamin E concentrations were significantly higher in Caretta than in Chelonia. This suggests that marine turtles follow the previously established chelonian pattern of carnivores having greater circulating concentrations of vitamin Ethan herbivores. The second study focused on vitamin concentrations in subadult Caretta and juvenile Chelonia from three Atlantic coastal habitats: Indian River Lagoon (IRL), the Nearshore Reef and Trident Submarine Basin. The disease fibropapillomatosis (FP) is prevalent in turtles from the IRL and the Nearshore Reef but not Trident Submarine Basin. Vitamin E concentrations differed significantly among turtles with different degrees of FP affliction. Turtles moderately afflicted with had significantly lower plasma concentrations of vitamin E compared with turtles not afflicted with the disease and as a result, may have compromised immune status. In contrast, however, severely afflicted turtles did not have lower circulating levels of vitamin E compared with those of mildly afflicted turtles. Vitamin A varied significantly among Chelonia from the three different developmental habitats. Turtles from the IRL had significantly higher concentrations of circulating vitamin A than turtles from both the Reef and Trident Basin. Chelonia on the Reef had significantly higher circulating concentrations of vitamin E than turtles in Trident Basin. Chelonia in the IRL had vitamin E concentrations that did not differ significantly from either the Nearshore Reef or Trident Basin turtles. Plasma vitamin E concentrations increased with decreasing straight-line carapace length in Chelonia. This is one of the largest scale vitamin studies conducted on reptiles and will contribute to conservation of marine turtles by providing baseline data on vitamins A and E. This information is useful for wildlife rehabilitators and zoos and aquaria with captive marine turtles. Effects of reproduction and disease on plasma concentrations of vitamins A and E are also discussed in this thesis.

Invasive fire ants are aggressive predators of ground nesting birds and reptiles and are spreading rapidly throughout tropical and temperate climates. Fire ants have been known to prey on a variety of reptile species, including threatened loggerhead sea turtles. The granular fire ant bait AMDRO® is being used on sea turtle nesting beaches to protect nests and hatchlings from these predators, however no studies have been conducted to thoroughly assess its effect on any reptile species. In this field study, I examined the impact of AMDRO® on hatching and emergence success, body condition, and orientation behavior in loggerhead sea turtles (Caretta caretta) in Juno Beach, Florida, USA. Pesticide granules were placed in a one-foot diameter circle directly above nest chambers during the final 5-10 days of incubation, which is representative of typical field applications of this pesticide on nesting beaches. Two controls were used in this study: cornmeal granules in soybean oil served as the vehicle control, and a second group of untreated control nests were left to incubate naturally, undisturbed. After a natural emergence, hatchlings were collected to calculate a body condition index (BCI). For a subset of the nests, 20 hatchlings were collected to perform orientation assays to assess the hatchlings’ ability to orient correctly toward the ocean, a visually mediated process that could be altered by visual impairments resulting from ADMRO® exposure. Three days following a mass emergence event, nests were excavated to collect hatching and emergence success data. Sand samples were collected to determine if the toxicant persisted in the environment or penetrated the egg chamber. Analyses indicated that the toxicant had no effect on hatchling morphology, hatching success, or emergence success. It also had no effect on the ability of hatchlings to orient toward the ocean. However, the pesticide granules attracted more predators than were seen at control nests. Thus, while AMDRO® might not directly impact reproductive success or hatchling behavior, it had the unanticipated effect of possibly increasing nest vulnerability to predators. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

The loggerhead sea turtle Caretta caretta is listed as threatened with extinction on the US Endangered Species Act. Those loggerhead turtles that nest on US beaches from North Carolina to north-east Florida are a genetically distinct subpopulation. This subpopulation is small, and may be declining. To obtain information about the migratory pathways of these turtles we tracked post-nesting movements of five females by satellite from their nesting beach at Wassaw Island, Georgia. Four turtles migrated north of the nesting beach, of which three moved to coastal waters of mid Atlantic states (total distances of 157-1,458 km). Efforts to reduce mortality of northern subpopulations of loggerhead turtles need to focus on identifying and reducing threats in north-east US waters.

Loggerhead sea turtles nest on either the Atlantic or Gulf coast of Florida. The hatchlings from these nests migrate offshore in opposite directions. The purpose of my study was to determine if Gulf coast hatchlings use magnetic maps, as Atlantic coast hatchlings do, both to locate areas favorable for survival in the Gulf of Mexico and to orient appropriately within surface currents that could transport them into the Atlantic Ocean. To find out, I presented Gulf coast hatchlings with magnetic fields corresponding to different locations inside the Gulf, and within currents leading into (Florida Straits) and within (Gulf Stream) the western portion of the Atlantic Ocean. I conclude that Gulf coast hatchlings (i) use a high resolution magnetic map for navigation within the Gulf of Mexico, (ii) initially remain within the eastern Gulf, but later may (iii) gain entry into currents that transport them into Atlantic waters. / by Maria W. Merrill. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

South Florida's loggerhead (Caretta caretta), green (Chelonia mydas) and leatherback (Dermochelys coriacea) sea turtles hatchling have environmentally determined sex. The in situ nest mean hatchling sex ratios (SR) were highly female-biased : loggerhead F=0.89) and green turtle F=0.81; leatherback's SR was nearly balanced (0.55F). Nest temperatures and SRs differed between leatherbacks and loggerhead and green turtles. The latter two did not differ. The loggerhead response parameters were estimated within biological limitations by both 50-65% of incubation and mean middle 1/3 temperature. The maximum middle 1/3 temperature was the best-fit predictor for green turtles. No best-fit sex ratio-temperature response could be identified for leatherbacks. Clutches incubating under natural conditions can vary greatly in SR ; TRT differences may account for differences among species' sex ratios. / by Micah Marie Rogers. / Thesis (M.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

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. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Florida’s sea turtle populations are increasing due to conservation efforts; however, sea turtle species are vulnerable to climate change. Turtles exhibit temperaturedependent sex determination, in which nest environment influences sex. Environmental changes may produce altered sex ratios that limit reproduction potential; therefore hatchling sex ratios should be monitored. Hatchlings are not externally sexually dimorphic, making sex identification difficult. This study established baseline plasma hormone concentrations in hatchling and post-hatchling green (Chelonia mydas) and loggerhead (Caretta caretta) sea turtles using High Performance Liquid Chromatography. Five hormones were assayed and were present in the majority of samples (testosterone: N.D.-10.12, progesterone: N.D.-0.43, estradiol: N.D.-4.78, estriol: N.D.-5.55 and estrone: N.D.-1.67 μg/mL). Plasma hormones did not distinguish hatchling sex because male and female ranges overlapped. Hormone concentrations varied with sex but also with incubation temperature, indicating that climate change could impact hatchling and posthatchling hormone profiles and thus could impact future fitness. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

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

Sea turtle hatchlings emerge from their nest and quickly crawl to the surf. During the crawl, hatchlings may encounter threats, biotic and abiotic, which can affect their ability to successfully reach the surf. The impact of these threats on hatchling survival during that crawl is largely undocumented. Current methods used to estimate cohort recruitment rely heavily on nest inventory data. This method, however, does not account for post-emergent hatchling mortality that occurs during the crawl. During the 2017-2018 nesting seasons, I quantified the fates of 1,379 loggerhead (Caretta caretta) hatchlings from 26 nest emergences during their crawl from the nest to the surf on the east and west coasts of Florida. I documented hatchling fates at 5 Florida nesting beaches: Wabasso, Boca Raton, Keewaydin Island, Naples, and Anna Maria Island. Overall, 6.5% of all emergent hatchlings died during the crawl from the nests to the surf. Ghost crabs, night herons, foxes, and coyotes killed hatchlings and photopollution and barriers on the beach (both abiotic threats) caused hatchling mortality. Anthropogenic (abiotic) threats accounted for more mortality than did predators. In order to assess how beach urbanization impacts hatchling mortality, I categorized each study site as urban (Wabasso and Naples), intermediate (Anna Maria Island and Boca Raton), or natural (Keewaydin Island) based on the relative levels of shoreline development and human activity at each beach. Sites with intermediate levels of urbanization accounted for greater levels of hatchling mortality than at other beaches due to the absolutely larger numbers of hatchlings lost to a disorientation event and to a beach barrier. Given the small numbers of emergences, at all sites, only a small proportion of the hatchlings mortalities (e.g., between 3 and 12 percent), site type could not be rigorously used as a discriminator. My results provide a better understanding of how specific environmental threats contribute to hatchling mortality. While nest-to-surf mortality is relatively low, its cumulative costs add up to several hundreds of thousands of hatchlings. Armed with this information, nesting beach managers can assess risks and focus their efforts to implement the most effective management practices to minimize losses of this imperiled species. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection