Thesis (M. Sc.)--College of William and Mary. / Vita. Includes bibliographical references (leaves 115-122).

The goal of this study was to determine if hatching synchrony occurs in loggerhead sea turtle nests and if it does, what mechanism(s) promote that synchrony. Synchrony may occur because oviposition takes place during a single evening, and because incubation temperatures within the nest show relatively little variation; thus, rates of embryonic development among the eggs are similar ("temporal synchrony hypothesis"). Alternatively, synchrony might be enhanced through embryo-to-embryo communication that stimulates and synchronizes development ("coordinated hatching hypothesis"). Experiments were designed to distinguish between these two hypotheses. I found that if only a few embryos survive, temporal synchrony occurs. However, if many embryos survive, the duration of incubation and hatching shortens, presumably because embryonic movements inside soft-shelled eggs are detected by and transmitted between eggs and stimulate development, expediting hatching synchrony. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

Under the expected warmer temperatures due to climate change, sea turtle embryos may be subjected to thermal conditions detrimental to nest success and hatchling quality; one trait which may be negatively affected is cognitive ability. In this study, loggerhead sea turtle eggs were acquired from Boca Raton, FL and lab incubated under two female-producing temperatures: an “optimal” temperature of 31°C and a sublethal temperature of 33°C. Cognitive ability of post-hatchlings, assessed via associative learning and reversal was investigated using a y-maze. The sublethal temperature decreased incubation duration, hatch success, hatchling growth rates and produced smaller hatchlings with significantly more scute anomalies. Hot hatchlings performed worse on the reversal, taking longer to train, and thus hint at an effect of incubation temperature on cognitive flexibility in loggerhead turtles. With temperatures rising on beaches in South Florida, this study provides evidence of further potential threats to hatchling quality and potentially even survival. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

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.

Loggerhead sea turtles (Caretta caretta) are listed as threatened under the Endangered Species Act and are protected both on nesting beaches and in United States waters. Loggerhead sea turtles are long-lived species and are most easily studied on the beaches during the nesting season. Bald Head Island, North Carolina has one of the highest density nesting beaches of loggerhead sea turtles in the turtle's northern range on the East Coast of the United States. Key life history parameters were estimated and applied to a population model using 16 years of data from a mark-recapture study on the loggerhead sea turtle nesting population on Bald Head Island, North Carolina. The beach survey conducted on the island only allowed for the capture of adult female sea turtles during the breeding state even though females may spend multiple years in the unobservable non-breeding state. The majority of females captured over the last 16 years have never been recaptured at the original capture site. These transients in the data coupled with unobservable states violate the assumption of equal catchability in the available single state mark-recapture models. Therefore, a multistate mark- recapture model originally developed for leatherback sea turtles was applied to the Bald Head Island loggerhead population. Multistate modeling provides a new technique to estimate sea turtle demographic parameters in which all model assumptions can be met. The multistate model outputs female survival rates, capture probability, and transition probabilities between breeding and non-breeding states. A correction factor for trap-dependence and transients was included given that both factors tested significant in the global model goodness-of-fit tests. The estimates of annual adult survival rate and breeding transitions were then used to project population size for the northern subpopulation. For the first time, estimation error around estimates of benthic juvenile and adult survival rates was included in a loggerhead sea turtle model. I explored the effects of estimation error, three levels of clutch frequency, and larger TED openings on population growth rate and on the probability of reaching a nesting recovery threshold. The nesting recovery threshold was based upon recovery criteria from the Federal Recovery Plan and set as the probability of reaching 12,800 nests/season in the states of North Carolina, South Carolina, and Georgia within a 50 year time period. The results of this study provide important information to guide future management and research. / Master of Science

Loggerhead sea turtles in coastal waters often sustain injuries from vessel impacts. The influences of vessel hull configuration and propulsion system type on the incidence and severity of wounds in turtle/vessel interaction were investigated. Full-scale field tests using two vessels with deep-vee hulls were performed. An artificial carapace with a sandwich composite design of a closed-cell polyurethane foam core with faces constructed of polyester resin infused with glass microspheres was developed. As a basis for comparison, a number of cold-stunned green turtle carcasses were also used in the field experiments. Two vessels, a 5.4 m boat with an inboard jet-drive engine and a 7.3 m boat with an outboard 4-bladed propeller, were operated at planing speed, 40 km/h. The field test results revealed similar patterns and severity of injuries between the synthetic turtles and the green turtle carcasses. Statistical analysis of the field test results indicated the influence of hull type alone on the severity of turtle damage was minimal, and none of the tests conducted using a jet drive engine resulted in injuries to the shell that would be considered lethal, regardless of the vessel hull type, speed, or the animal's depth in the water at impact. Conversely, injuries occurring as a result of propeller and/or skeg impact at planing speed were always classified as fatal. A finite element analysis of the artificial turtle was performed to determine the force at which a carapace fractures from hull impact alone. The results of the finite element analysis suggest that hull impacts of common recreational jet-propulsion vessels are unlikely to cause lethal carapace fractures in loggerhead sea turtles.

No description available.

The eastern race of the Loggerhead shrike (Lanius ludovicianus ssp. migrans) is a grassland bird federally listed as endangered. There are approximately 30 pairs remaining in the Canadian wild today. Captive breeding and release programs have been developed in Canada to help alleviate the decline. However, little is known about the fate of the released birds and the factors influencing their reproductive success. To help in the understanding of the movement, behaviour and survival of the shrikes post-release, we tested whether radio telemetry was an effective technique to follow these birds. Despite limited behavioural effects in captivity, a tail-mount was not suitable for released Loggerhead shrikes due to unreliable retention times. The second portion of this study addressed the factors influencing reproductive success in captivity, including breeding behaviour and individual characteristics. Distance between individual pairs in their cages, female nesting activity and male origin were the best predictors of success. Recommendations for managers are made.

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