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.

Although sexual stereotypes paint males as being promiscuous and females as being choosy in order to increase their reproductive success, multiple mating by females is widespread and females of many taxa often produce progeny sired by multiple males – but why? In species in which there are no direct benefits associated with mating, females may adopt promiscuous mating strategies to increase their fitness through the acquisition of genetic benefits. Here, I examine the genetic mating system of map turtles, Graptemys geographica in Lake Opinicon. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males. There did not appear to be any relationship between female body size and frequency of multiple paternity. There was a marginally significant effect of multiple paternity on hatching success and survival of clutches, but there was no effect on hatchling morphology or locomotor performance.

Hatchling marine turtles exhibit a positive phototaxis by crawling toward the lowest and brightest horizon when they emerge from nests on the beach at night, which should lead them to the ocean (“seafinding”). Previous research with cheloniid (loggerhead and green turtle) hatchlings demonstrated that the perceptual spectral sensitivities are well below the light available on the beach regardless of lunar phase. The goal of this research was to determine the perceptual spectral sensitivities of leatherback hatchlings, the most distantly related of all extant sea turtle species. This study revealed that, like cheloniids, leatherbacks are most sensitive to shorter wavelengths (< 500 nm). However, leatherbacks were 10 – 100x less sensitive than cheloniids at all tested wavelengths. This difference in sensitivity corresponds with increased crawl duration and circling behavior under new moon conditions when light levels are lowest and the difference in radiance between the landward and seaward direction is small. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

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

The leatherback sea turtle (Dermochelys coriacea) is facing global declines; however, the Florida stock is generally increasing. Various studies have identified threats to sea turtles, but there is a need to quantify population-level threats. I used external examination and blood analyses of leatherbacks nesting on northern Palm Beach County, Florida beaches to understand the impact(s) that physical injuries have on this population. Notable injuries were present on 118 of 167 (70.7%) turtles. Fisheries injuries were more prevalent than other anthropogenic injuries; however, there was a higher overall prevalence of natural injuries. There were no notable findings from my blood analyses. My results suggest that while natural injuries are more common than anthropogenic injuries in the nesting population of Florida leatherbacks, anthropogenic injuries are more likely to result in severe traumatic wounds. Future investigation of overlap in leatherback migratory routes and foraging grounds with various threats could further protect this species. / Includes bibliography. / Thesis (MS)--Florida Atlantic University, 2021. / 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

No description available.

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.

Seagrass meadows are a crucial foraging habitat for marine megaherbivores. The Red Sea hosts two megaherbivore species, the green turtle Chelonia mydas and the dugong Dugong dugon, along with twelve seagrass species. Seagrass habitats in the Saudi Arabian coast of the Red Sea are currently under pressure from large scale coastal developments. I used multiple methods to assess seagrass and megaherbivore densities in Al-Wajh lagoon, a unique semi-enclosed bay on the northeastern coast of the Red Sea that is currently targeted for development. Seagrasses were assessed using quadrat surveys while megaherbivores censuses were conducted by both unmanned aerial vehicles (UAV) and boat-based observers. Both seagrass and sea turtles were patchily distributed throughout the bay. Dugongs were never encountered during surveys but feeding trails and off-effort encounters suggest at least occasional use of the area. While there were some qualitative patterns between seagrass composition and feeding trail/sea turtle abundance, there was not enough data to achieve statistical significance. The UAV generally outperformed boat-based surveys, but the inability of the drone to distinguish turtles through dense seagrass coverage is a methodological limitation that should be overcome by using hyperspectral cameras in future work. Overall, my results highlight the importance of ground truthing habitat maps, reveal interesting questions for additional study, and provide some direction for future research and conservation efforts within Al-Wajh Lagoon.

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