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- Title
- Estimating predation levels and site-specific survival of hatchling loggerhead sea turtles (Caretta caretta) from south Florida beaches.
- Creator
- Whelan, Christie L., Florida Atlantic University, Wyneken, Jeanette
- Abstract/Description
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Few studies document mortality rates for hatchling sea turtles during their migration away from the nesting beach. This study quantifies and compares nearshore predation rates on loggerhead hatchlings (Caretta caretta) at several locations in southern Florida. Hatchlings were followed by observers in kayaks during the first 15 min of the migration away from the beach. The overall observed predation rate (4.6%) is similar to a previous estimate (5%) from a natural high density Florida nesting...
Show moreFew studies document mortality rates for hatchling sea turtles during their migration away from the nesting beach. This study quantifies and compares nearshore predation rates on loggerhead hatchlings (Caretta caretta) at several locations in southern Florida. Hatchlings were followed by observers in kayaks during the first 15 min of the migration away from the beach. The overall observed predation rate (4.6%) is similar to a previous estimate (5%) from a natural high density Florida nesting beach, and lower than at a hatchery site. Predation rates were higher on Florida's southeast coast than the southwest coast. Predation increased towards the end of the hatching season. Results suggest that currently, hatchling mortality rates are relative low in Florida's shallow nearshore waters. Given the lack of growth by loggerhead populations, the cumulative mortality must be high after hatchlings depart shallow coastal waters.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13259
- Subject Headings
- Sea turtles--Florida--Atlantic Coast, Loggerhead turtle--Mortality, Predation (Biology)
- Format
- Document (PDF)
- Title
- Beach dynamics, beachfront development, and climate change: Interactions that impact sea turtle nesting beaches.
- Creator
- Bladow, Rachel A., Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Climate change will expose sea turtle nests to higher temperatures and more storms; both may negatively impact sea turtle nest success. In this study, unhatched eggs were collected from the Boca Raton, Florida beach and developmental stage at embryonic death determined. Elevated nest temperatures increased embryonic mortality, and the most significant relationship was between mortality and the percent of time embryos were exposed to temperatures above 34°C. Loggerhead turtles exhibited higher...
Show moreClimate change will expose sea turtle nests to higher temperatures and more storms; both may negatively impact sea turtle nest success. In this study, unhatched eggs were collected from the Boca Raton, Florida beach and developmental stage at embryonic death determined. Elevated nest temperatures increased embryonic mortality, and the most significant relationship was between mortality and the percent of time embryos were exposed to temperatures above 34°C. Loggerhead turtles exhibited higher rates of mortality compared to green turtles at temperatures above 34°C. Only loggerhead nests were exposed to inundation, but embryonic mortality did not differ from noninundated nests. Beach profiles across the nesting season were also determined. A major storm altered the beach more in areas of coastal development; however, this was impacted by a nourishment project and the presence of a structured inlet. Future management strategies may need to protect sea turtle nests from extended periods at elevated temperatures.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00005926
- Subject Headings
- Dissertations, Academic -- Florida Atlantic University, Sea turtles--Ecology., Loggerhead turtle--Florida., Sea turtles--Nests., Climate change
- Format
- Document (PDF)
- Title
- Impact of the red imported fire ant (Solenopsis invicta ) on two species of sea turtle hatchlings.
- Creator
- Krahe, Holly B., Florida Atlantic University, Wetterer, James K.
- Abstract/Description
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Although the red imported fire ant (Solenopsis invicta ) is known to kill sea turtle hatchlings, little research has focused on sub-lethal effects of ant attacks on hatchlings emerging from nests. Sea turtle hatchlings of two species (Caretta caretta and Chelonia mydas) exposed to fire ants during incubation and emergence were collected on Juno Beach, Florida. Hatchlings were maintained for ten days in a common saltwater outdoor pool at the Marinelife Center, Juno Beach. Hatchlings showing...
Show moreAlthough the red imported fire ant (Solenopsis invicta ) is known to kill sea turtle hatchlings, little research has focused on sub-lethal effects of ant attacks on hatchlings emerging from nests. Sea turtle hatchlings of two species (Caretta caretta and Chelonia mydas) exposed to fire ants during incubation and emergence were collected on Juno Beach, Florida. Hatchlings were maintained for ten days in a common saltwater outdoor pool at the Marinelife Center, Juno Beach. Hatchlings showing pustules diagnostic of S. invicta stings were compared to non-stung controls in terms of survival, growth (mass and SCL) and initial crawling strength. Loggerhead hatchlings showed a significant decrease in survival, growth, and crawling strength when stung by fire ants. In contrast, no significant differences were seen in the survival, growth, and crawling strength of green turtle hatchlings when stung by fire ants.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13252
- Subject Headings
- Fire ants--Venom--Physiological effect, Loggerhead turtle--Mortality, Green turtle--Mortality, Sea turtles--Florida
- Format
- Document (PDF)
- Title
- Visual wavelength discrimination by the loggerhead turtle, Caretta caretta.
- Creator
- Young, Morgan, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Little is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles...
Show moreLittle is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles could detect. Second, I used food to train older turtles to swim toward one light color, and then to discriminate between the rewarded light and another light color ; lights were presented at intensities equally above the phototaxis threshold. Lastly, I varied light intensity so that brightness could not be used as a discrimination cue. Six turtles completed this task and showed a clear ability to select a rewarded over a non-rewarded color, regardless of stimulus intensity. Turtles most rapidly learned to associate shorter wavelengths (blue) with food. My results clearly show loggerheads have color vision. Further investigation is required to determine how marine turtles exploit this capability.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3352879
- Subject Headings
- Color vision, Visual discrimination, VIsual perception, Selectivity (Psychology), Photoreceptors, Loggerhead turtle, Orientation, Sea turtles, Orientation, Animal navigation
- Format
- Document (PDF)
- Title
- Can hatchlings exposed to beach lighting recover, and orient normally offshore?.
- Creator
- Lorne, Jacquelyn Kay, Florida Atlantic University, Salmon, Michael
- Abstract/Description
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Artificial lighting disrupts sea turtle hatchling orientation from the nest to the sea. I studied how a light-induced landward crawl affects the ability of hatchlings to later crawl to the sea, and swim offshore from a dark beach. A brief (2 min) landward crawl had no effect on orientation, as long as waves (used as an orientation cue while swimming) were present. In the absence of waves (a flat calm sea), landward-crawling hatchlings failed to swim offshore while those crawling seaward were...
Show moreArtificial lighting disrupts sea turtle hatchling orientation from the nest to the sea. I studied how a light-induced landward crawl affects the ability of hatchlings to later crawl to the sea, and swim offshore from a dark beach. A brief (2 min) landward crawl had no effect on orientation, as long as waves (used as an orientation cue while swimming) were present. In the absence of waves (a flat calm sea), landward-crawling hatchlings failed to swim offshore while those crawling seaward were well oriented. A longer (2 h) landward crawl impaired the ability of hatchlings to crawl to the sea. These results demonstrate that previous exposure to artificial lighting compromises subsequent orientation, both on land and in the sea. On the basis of my results, I suggest several changes to current management practices, currently used when releasing misoriented turtles in the wild.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13400
- Subject Headings
- Sea turtles--Atlantic Coast (U S )--Geographical distribution, Light pollution, Animal orientation, Loggerhead turtle--Orientation, Animal navigation
- Format
- Document (PDF)
- Title
- Do embedded roadway lights protect sea turtles?.
- Creator
- Bertolotti, Lesley L., Florida Atlantic University, Salmon, Michael
- Abstract/Description
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Pole-mounted street lighting on coastal roadways is often visible in adjacent areas. At roadways near sea turtle nesting beaches, these lights can disrupt the nocturnal orientation of hatchlings as they crawl from the nest to the sea. Our objective was to determine if an alternative lighting system (light-emitting diodes, embedded in the roadway pavement) prevented orientation disruption of loggerhead hatchlings. Hatchlings at the beach oriented normally when the embedded lights were on, or...
Show morePole-mounted street lighting on coastal roadways is often visible in adjacent areas. At roadways near sea turtle nesting beaches, these lights can disrupt the nocturnal orientation of hatchlings as they crawl from the nest to the sea. Our objective was to determine if an alternative lighting system (light-emitting diodes, embedded in the roadway pavement) prevented orientation disruption of loggerhead hatchlings. Hatchlings at the beach oriented normally when the embedded lights were on, or when all lighting was switched off. However, turtles showed poor orientation when exposed to pole-mounted street lighting. Light measurements revealed that street lighting was present at the beach, whereas embedded lighting was absent. I conclude that embedded lighting systems restrict light scatter, leaving adjacent habitats dark, and therefore protect the turtles from artificial lighting allowing for normal seafinding.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13203
- Subject Headings
- Loggerhead turtle, Animal navigation, Animal orientation, Sea turtles--Orientation, Exterior lighting--Environmental aspects, Light pollution
- Format
- Document (PDF)
- Title
- Impact of the Fire Ant Pesticide Hydramethylnon (AMDRO®) on Loggerhead Sea Turtle Reproductive Success and Hatchling Quality.
- Creator
- Smith, Heather, Salmon, Michael, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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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...
Show moreInvasive 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.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013264
- Subject Headings
- Fire ants, Loggerhead turtle--Effect of pesticides on, Caretta caretta
- Format
- Document (PDF)
- Title
- False crawls by loggerhead sea turtles in Palm Beach County, Florida.
- Creator
- Leech, Anna, Harriet L. Wilkes Honors College
- Abstract/Description
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In Florida, loggerhead sea turtle (Caretta caretta) nesting populations are in decline, and human presence on beaches during nesting season can create an array of problems for the sea turtles. Volunteers and workers from the Loggerhead Marinelife Center collected nesting data from 2001 to 2005 along a 9.7 km stretch of Jupiter and Juno Beach, in Palm Beach County, Florida. Using these data, I found that human presence appears to have a negative impact on false crawl rates. The rate of false...
Show moreIn Florida, loggerhead sea turtle (Caretta caretta) nesting populations are in decline, and human presence on beaches during nesting season can create an array of problems for the sea turtles. Volunteers and workers from the Loggerhead Marinelife Center collected nesting data from 2001 to 2005 along a 9.7 km stretch of Jupiter and Juno Beach, in Palm Beach County, Florida. Using these data, I found that human presence appears to have a negative impact on false crawl rates. The rate of false crawl was significantly higher on weekends than on weekdays(χ2 = 6.3, p < 0.05), and in areas with continuous public access than in areas with no public access(χ2 = 69.0, p < 0.0001). However, there was no significant difference in the number of nests laid on weekends versus weekdays(χ2 = 0.6, p > 0.05), although there are still other, less obvious negative effects caused by false crawling, and even nesting, while humans are in the vicinity. Even though it is impractical to try to keep people off the beach at night, it is important to increase awareness of the negative impacts that human presence may have on sea turtle nesting in order to help reverse the decline in the population of loggerhead sea turtles.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/FAU/77673
- Subject Headings
- Sea turtles, Wildlife conservation, Loggerhead turtle, Sea turtles, Orientation
- Format
- Document (PDF)
- Title
- Plasma Steroid Hormones in Loggerhead and Green Sea Turtle Hatchlings.
- Creator
- Reis, Andrea, Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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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...
Show moreFlorida’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.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004626
- Subject Headings
- Sea turtles--Embryology., Sea turtles--Habitat--Conservation., Sex determination, Genetic., Loggerhead turtle--Effect of temperature on., Developmental genetics.
- Format
- Document (PDF)
- Title
- Nest-to-surf mortality of loggerhead (Caretta caretta) sea turtle hatchlings on Florida’s east coast in 2016.
- Creator
- Erb, Victoria, Wyneken, Jeanette, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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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...
Show moreWorldwide, 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.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004934, http://purl.flvc.org/fau/fd/FA00004934
- Subject Headings
- Sea turtles--Mortality--Florida., Loggerhead turtle--Mortality., Predation (Biology), Sea turtles--Orientation., Animal navigation., Fire ants--Venom--Physiological effect.
- Format
- Document (PDF)
- Title
- Predicting leatherback sea turtle sex ratios using spatial interpolation of nesting beach temperatures.
- Creator
- Weston, Emily G., Wyneken, Jeanette, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Sex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand...
Show moreSex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand temperatures from May- August and across the spatial range of leatherback nesting habitat. I spatially interpolated those temperatures to create maps that predicted temperatures for all nests incubating on SPWNR. Nest temperatures were also directly measured and compared with predicted nest temperatures to validate the prediction model. Sexes of dead-in-nest hatchlings and full term embryos were used to confirm the sex-temperature response. The model showed that microclimatic variation likely impacts the production of both sexes on SPNWR.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fau/fd/FA0004071
- Subject Headings
- Leatherback turtle -- Habitat -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Loggerhead turtle -- Effect of temperature on, Sandy Point National Wildlife Refuge (United States Virgin Islands), Sea turtles -- Nests -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Sex determination, Genetic, Sex ratios, Vegetation dynamics
- Format
- Document (PDF)