There are four distinct subpopulations of loggerhead sea turtles (Caretta caretta) in Florida as determined behaviorally by geographic fidelity, and genetically by mitochondrial haplotypes. The South Florida subpopulation consists of females nesting on the southeastern and southwestern coasts of Florida and their offspring. Previous research shows that west coast hatchlings exhibit higher levels of nocturnal swimming during the postfrenzy period than east coast hatchlings. This study attempted to determine how these differences in migratory behavior develop. A reciprocal translocation experiment was conducted to distinguish between environmental and genetic factors. No consistent differences in hatchling swimming behavior were seen based on geography. Movement of nests resulted in lower levels of nocturnal swimming behavior in hatchlings compared to hatchlings that emerged from natural nests, suggesting that the relocation of nests may not provide a natural incubation environment for developing hatchlings. / by Jeffrey Guertin. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

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.

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

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

Egg predation may be the most important mortality factor for North American turtles. This predation can destroy 50-90% of nests in an area. The major predators are striped skunks (Mephitis mephitis) and raccoons (Procyon lotor). Despite differences in their habits and diet, these species appear equally efficient in turtle egg predation, even though these eggs represent a very small portion of their annual food intake. Sight, olfaction, touch and hearing could be used by these predators to find the nests. The aim of this study was to document intra and inter-specific differences in the perception of possible nest-cues used by raccoon and striped skunk. Choice-tests based on food-conditioning were carried out with two visual cues (dark and smooth surface), one olfactory cue (turtle urine) and one tactile cue (soil compaction). Subject performances (number of trials to obtain 80% success rate in the different tests) were compared to assess intra and inter-species, and skunk inter-age differences in sensory perception and learning abilities. As expected raccoons learned the tactile cue discrimination faster than the visual cue discriminations. The tactile cue discrimination was learned as fast as the olfactory cue. As expected skunks learned the olfactory cue discrimination faster than other cue discriminations. When compared, the olfactory cue appeared to be as important for both species even though raccoons had faster learning rates than skunks in all the tests except for one visual test. Juvenile skunks learned faster than adult skunks with four out of six juveniles performing better in the olfactory test. Olfaction may play an important role in nest localization by raccoons and skunks, and sight may also play a role for raccoons. Learning turtle nest cues while with their mother could facilitate their future ability in locating turtle nests.

No description available.

Roads are long linear features on the landscape that impact wildlife and their habitats. Among all forms of wildlife turtles are one of the most negatively affected by roads. Wildlife biologists and civil engineers have developed and implemented road design measures to mitigate the negative effects associated with roads. One common approach used to reduce road mortality and to facilitate movement of turtles is to construct a road mitigation system. There are currently 28 road mitigation systems for wildlife in Massachusetts, of which 14 were specifically built for turtles. We identified all known systems in Massachusetts and collected site and structural design information for each. In addition, we also examined the relative effectiveness of experimental passages for freshwater turtles. Structures were evaluated with respect to how their height, width, and position (at or below-grade), influenced the movements of painted turtles. A total of 190 turtles were exposed to the experiential trials and their behavior was characterized by 3 response variables (Total time to complete the trial, Total hesitations observed, and Success based on no hesitations and completion of the trial in less than 120 minutes). We concluded that painted turtles exposed to below-grade tunnels were less hesitant and traveled faster through them as the tunnel size increased from 0.6 m x 0.6 m to 1.2 m x 1.2 m. The 1.2 m x 1.2 m tunnel size overall proved to be the size with the fewest hesitations observed, fastest total times, and highest success rate.

Understanding the movements and behavior of hawksbi1l sea turtles is vital to their protection, but existing data on these subjects are insufficient. The objectives of this study were 1) to monitor internesting movements and surfacing behavior of hawksbill sea turtles nesting at Buck Island Reef National Monument, St. Croix, and 2) to describe post-nesting movements of Buck Island hawksbills. Surfacing behavior and presence or absence of tagged turtles W(> :-t' monitored 24 hr a day by a computerized tracking system using pulse-coded transmitters. Internesting and post-nesting movements were tracked using satellite transmitters on the ARGOS system. No clear trends were apparent in total time spent at the surface. either during an internesting interval or when comparing day and nigh~ behavior; behavior was turtle and interval-specific (n=3). The number of times a turtle surfaced over an internesting interval also varied among turtles, but all turtles surfaced more frequently at the end of an internesting interval (P < 0.05). No differences were found in the number of times turtles surfaced during the day versus night, with the exception of one turtle which surfaced more frequently during the daytime. Comparisons of day and nighttime activity among turtles revealed that surfacing behavior was similar among the turtles studied with the exception of one turtle that spent significantly more time at the surface than the other turtles during both day and night. Internesting movements were found to be extensive for 2 of 3 turtles tracked t with turtles moving from 197 km to 845 km from Buck Island. The third turtle remained within 1 km of Buck Island. Tagged turtles left the Buck Island vicinity immediately after nesting for the season. Two turtles tracked with pulse-coded transmitters through the end of their nesting effort were last heard less than 24 hr after laying their last nest. Satellite tagged turtle T3, tracked for 10 months, traveled between the British Virgin Islands and Puerto Rico for 3 months, then became resident off the southern coasts of St. Thomas and St. John, USVI. Turtle T3 left this area occasionally on short-duration excursions, but always returned. Satellite tagged turtle T8, tracked for 1.5 months, moved to Puerto Rico immediately after completing nesting for the season, and was subsequently located off the coast of the Dominican Republic t St. Vincent (The Grenadines), and the northern coast of Venezuela. A third turtle (TIl) was located only once after laying her last nest; at the island of Anegada, BVI. Frequent failure to receive locations from satellite transmitters that were known to be attached and functional suggests that turtles may not stay at the surface long enough for transmissions to reach the ARGOS satellites. / Master of Science

No description available.

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.