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- Title
- EVIDENCE FOR THE INDEPENDENT EVOLUTION OF VISUAL PERCEPTION DURING SEAFINDING BY HATCHLING LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA).
- Creator
- Trail, Samantha E., Salmon, Michael, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
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...
Show moreHatchling 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.
Show less - Date Issued
- 2021
- PURL
- http://purl.flvc.org/fau/fd/FA00013790
- Subject Headings
- Leatherback turtle, Dermochelys coriacea, Phototaxis, Spectral sensitivity
- Format
- Document (PDF)
- Title
- IMPACT OF SARGASSUM ACCUMULATIONS ON LOGGERHEAD HATCHLING RECRUITMENT TO NEARSHORE WATER ON A RAKED URBAN NESTING BEACH IN FLORIDA.
- Creator
- Schiariti, Joshua P., Salmon, Michael, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Hatchling loggerhead turtles emerge from subsurface nests on the beach at night, crawl down the beach and enter the sea. Recently, increases in a floating algae (Sargassum) has been reported in the mid-Atlantic and the Caribbean, resulting in large algal wrack on Florida beaches. The purpose of my study was to determine if these accumulations acted as a barrier, preventing hatchlings from completing their crawl to the sea. To address this issue I recorded seasonal changes in Sargassum density...
Show moreHatchling loggerhead turtles emerge from subsurface nests on the beach at night, crawl down the beach and enter the sea. Recently, increases in a floating algae (Sargassum) has been reported in the mid-Atlantic and the Caribbean, resulting in large algal wrack on Florida beaches. The purpose of my study was to determine if these accumulations acted as a barrier, preventing hatchlings from completing their crawl to the sea. To address this issue I recorded seasonal changes in Sargassum density and directly observed when, and under what circumstances, hatchlings could cross the wrack. There was a significant overlap between when Sargassum accumulation peaked and when the turtles emerged, with the result that hatchling recruitment was significantly reduced (by~22%) during the 2020 nesting season. I conclude that algal accumulations represent a significant threat that may impede the recovery of loggerhead populations, that are currently threatened or endangered worldwide.
Show less - Date Issued
- 2021
- PURL
- http://purl.flvc.org/fau/fd/FA00013806
- Subject Headings
- Loggerhead turtle, Sargassum, Conservation biology
- Format
- Document (PDF)
- Title
- WHAT MECHANISMS UNDERLIE SYNCHRONOUS HATCHING IN LOGGERHEAD TURTLE NESTS?.
- Creator
- Field, Angela, Salmon, Michael, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
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...
Show moreThe 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.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013505
- Subject Headings
- Loggerhead turtle, Nests, Eggs—Incubation, Synchrony
- 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
-
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
- Long-term analyses (1986-2018) of the Loggerhead Sea Turtle (Caretta caretta) nesting data from Keewaydin Island, Florida.
- Creator
- Hoover, Shelby R., Salmon, Michael, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Few studies on marine turtles focus on the variation in reproductive performance of individual females. I use a long-term nesting data set (1986 – 2018) of individual loggerheads including information on 1,854 individuals, of which 853 were seen nesting multiple times. During this time, emergence success has declined while the number of females nesting, and the number of nests deposited has increased. Declining emergence success can be linked to an increase in predation in most recent years;...
Show moreFew studies on marine turtles focus on the variation in reproductive performance of individual females. I use a long-term nesting data set (1986 – 2018) of individual loggerheads including information on 1,854 individuals, of which 853 were seen nesting multiple times. During this time, emergence success has declined while the number of females nesting, and the number of nests deposited has increased. Declining emergence success can be linked to an increase in predation in most recent years; however, this does not fully explain the decline in emergence success over all years. Females were found to vary in productivity. Successful females were larger and deposited more eggs in nests. This study shows that an increasing in nesting numbers does not mean that productivity is increasing proportionally and that recovery efforts are uniformly successful. This study is also a powerful tool for understanding the reproductive strategies of individual female loggerheads.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013381
- Subject Headings
- Loggerhead turtle--Florida, Reproduction, Sea turtles--Nests, Predation (Biology)
- Format
- Document (PDF)
- Title
- Hawksbill nest site selection affects hatchling survival at a rookery in Antigua, West Indies.
- Creator
- Reising, Megan, Salmon, Michael, Stapleton, S
- Date Issued
- 2015-12-17
- PURL
- http://purl.flvc.org/fau/fd/FAUIR000185
- Format
- Citation
- Title
- Use Of Molecular Techniques To Understand The Spatial And Temporal Features Of The Oceanic Stage In Hawksbill Sea Turtles, Eretmochelys Imbricata; A Thesis Proposal.
- Creator
- Coppenrath, Christina, Salmon, Michael, Graduate College
- Abstract/Description
-
For highly migratory species, it is important to understand what habitats are used and what requirements are essential for growth and development. These migrations often span different political and regulatory boundaries, complicating conservation strategies. The hatchlings and post-hatchlings of most sea turtle species migrate to oceanic habitats where they remain for several years before returning to shallow developmental habitats. For critically endangered hawksbill turtle, Eretmochelys...
Show moreFor highly migratory species, it is important to understand what habitats are used and what requirements are essential for growth and development. These migrations often span different political and regulatory boundaries, complicating conservation strategies. The hatchlings and post-hatchlings of most sea turtle species migrate to oceanic habitats where they remain for several years before returning to shallow developmental habitats. For critically endangered hawksbill turtle, Eretmochelys imbricata, most research has concentrated on nesting ecology and very little is known about the posthatchling migration. Many sea turtles then spend years in different foraging habitats before reaching sexual maturity, and such foraging grounds typically represent a mixed stock of turtles from different nesting beaches. Mitochondrial DNA analysis can be used to estimate genetic stock structure of mixedstock foraging populations for sea turtles, and the duration of the post-hatchling oceanic stage can be estimated using stable isotope analysis and satellite telemetry. Our objectives are to determine the duration of the post-hatchling oceanic stage of development, to determine if the turtles sampled in a particular foraging habitat represent a biased or unbiased assortment of matrilineages, and to infer potential migratory pathways by investigating ocean currents between nesting beaches and the foraging site. Here we discuss our methods, to determine the duration of the post-hatchling oceanic stage and stock structure for immature hawksbills at a developmental foraging ground.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00005873
- Format
- Document (PDF)
- Title
- What Controls The Nocturnal Emergence Rhythm Of Hatchling Marine Turtles?.
- Creator
- Prio, Joseph D., Salmon, Michael, Graduate College
- Abstract/Description
-
Most marine organisms partition particular activities, such as growth, migration, reproduction, and hatching, to particular seasons, times of the day or night, or phases of the lunar cycle. The result is characterized as a “rhythm”. Scientists who study these rhythms generally ask two kinds of questions: why do they occur when they do that is, what is their survival value, and how are they controlled, physiologically? Hatchling marine turtles almost always emerge from their nests at night,...
Show moreMost marine organisms partition particular activities, such as growth, migration, reproduction, and hatching, to particular seasons, times of the day or night, or phases of the lunar cycle. The result is characterized as a “rhythm”. Scientists who study these rhythms generally ask two kinds of questions: why do they occur when they do that is, what is their survival value, and how are they controlled, physiologically? Hatchling marine turtles almost always emerge from their nests at night, then crawl down the beach to the sea and migrate offshore. By doing so at night they avoid lethally warm beach sands and diurnally active predators in the shallows. But these “survival value” explanations do not account for how the turtles, digging their way upward inside the nest toward the beach surface, know that it’s dark and time to emerge. The classic explanation for how they “know” is based upon surface sand temperatures. During the day, these sands can be very warm 50° C. When hatchlings digging upward encounter these heated sands, they stop digging until the sand cools, after sunset. But these observations fail to explain why in most studies, hatchlings rarely emerge from their nests at dawn or in the early morning, when the sand is still cool. To account for those observations, we hypothesize that the turtles must also possess a time sense that inhibits emergence during inappropriate times, such as shortly before or after sunrise.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00005909
- Format
- Document (PDF)
- Title
- Responses of green [chelonia mydas], loggerhead [caretta caretta], and leatherback turtles [dermochelys coriacea] to chemical odors.
- Creator
- Kedzuf, Stephanie C., Salmon, Michael, Graduate College
- Abstract/Description
-
The cues used by marine turtles to locate foraging areas in the open ocean are largely unknown, though field observations suggest that some species [especially the green turtle [Chelonia mydas], the loggerhead [Caretta caretta], and the leatherback [Dermochelys coriacea]] somehow locate areas of high productivity. Do they do so by orienting toward chemical cues in air, water, or both air and water? Previous studies have shown that loggerheads are capable of detecting airborne odors from...
Show moreThe cues used by marine turtles to locate foraging areas in the open ocean are largely unknown, though field observations suggest that some species [especially the green turtle [Chelonia mydas], the loggerhead [Caretta caretta], and the leatherback [Dermochelys coriacea]] somehow locate areas of high productivity. Do they do so by orienting toward chemical cues in air, water, or both air and water? Previous studies have shown that loggerheads are capable of detecting airborne odors from synthetic food [turtle pellets] as well as natural dimethyl sulfide [DMS], which is found in productive oceanic areas. However, responses were brief, and a capacity to orient was not investigated. We presented tethered loggerheads and leatherbacks to a laminar airflow that contained DMS or natural food odors [squid, shrimp, sargassum, and moon jellyfish]. We observed no tendency to orient upwind. Additional experiments examined if freeswimming loggerhead and green turtles would respond to squid odor presented in air or water with a visual stimulus [a small plastic ball suspended in the water present]. Both species showed significant increases in biting behavior when exposed to squid odor in air or water. We conclude that i. air currents carrying DMS or food do not induce turtles to orient upwind, ii. turtles can detect and respond to food odors either in air or underwater, and iii. only odors from food stimulate turtles to initiate feeding behavior. None of our results provide support for the hypothesis that turtles can locate distant sources of food in the ocean using odor cues.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00005826
- Format
- Document (PDF)
- Title
- Comparison of growth patterns in three species of juvenile sea turtles.
- Creator
- Pate, Jessica Hope, Salmon, Michael, Wyneken, Jeanette, Graduate College
- Abstract/Description
-
Sea turtles are most vulnerable to predators during early growth when they are small and relatively defenseless. Predation risk might be reduced by evolving effective behavioral as well as morphological defenses. Loggerhead Caretta caretta and green turtle Chelonia mydas neonates hide in weed lines. They also become wider faster than they increase in length, a pattern of positive allometry that may function to minimize the time during growth when they are vulnerable to gape-limited predators....
Show moreSea turtles are most vulnerable to predators during early growth when they are small and relatively defenseless. Predation risk might be reduced by evolving effective behavioral as well as morphological defenses. Loggerhead Caretta caretta and green turtle Chelonia mydas neonates hide in weed lines. They also become wider faster than they increase in length, a pattern of positive allometry that may function to minimize the time during growth when they are vulnerable to gape-limited predators. Virtually nothing is known about how young leatherbacks grow which might reduce their vulnerability to predators. To find out, we reared 30 hatchlings from 10 nests in the laboratory for up to 14 weeks, post-emergence. Once weekly, each turtle’s body proportions straight line carapace length, SCL; straight line carapace width, SCW were measured to yield an observed pattern of growth. That observed growth pattern was compared to an expected pattern in which the turtles retained their hatchling proportions as they grew larger isometric growth. We found that all of the leatherbacks showed allometric growth as their SCW increased more rapidly than their SCL. Thus as they grew, leatherbacks became proportionally wider, though this growth was not as pronounced as seen in loggerheads and green turtles. We also modeled vulnerability to gape-limited predators. Leatherbacks, like loggerhead and green turtles, were less vulnerable to predation when growing allometrically. These results provide insight into a little know sea turtle life stage and aids in understanding how morphology in early development may reduce predation risk.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00005846
- Format
- Document (PDF)
- Title
- A comparison of body proportions in juvenile sea turtles: how shape may optimize survival in a vulnerable life stage.
- Creator
- Pate, Jessica Hope, Salmon, Michael, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Marine turtles produce many offspring which offsets the high mortality experienced by turtles during early development. Juvenile mortality might be reduced by evolving effective behavioral as well as morphological anti-predator defenses. Body proportions of three species (Caretta caretta, Chelonia mydas, Dermochelys coriacea) of turtles were measured in the first fourteen weeks of development to examine how growth may mitigate predation by gape-limited predators. Growth was categorized as...
Show moreMarine turtles produce many offspring which offsets the high mortality experienced by turtles during early development. Juvenile mortality might be reduced by evolving effective behavioral as well as morphological anti-predator defenses. Body proportions of three species (Caretta caretta, Chelonia mydas, Dermochelys coriacea) of turtles were measured in the first fourteen weeks of development to examine how growth may mitigate predation by gape-limited predators. Growth was categorized as isometric if shape did not change during development or allometric if body shape did change. All three species showed allometric growth in carapace width; however it was less pronounced in the larger D. coriacea turtles. Allometric growth in carapace width decreased as all three species grew in size. When high predation occurs in early development, many species will favor rapid growth into a size refuge. Juvenile sea turtles may optimize their survival by growing allometrically when predation risk is the greatest.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004223, http://purl.flvc.org/fau/fd/FA00004223
- Subject Headings
- Predation (Biology), Sea turtles -- Growth, Sea turtles -- Mortality, Sea turtles -- Population viability analysis
- Format
- Document (PDF)
- Title
- The role of air and waterborne odors in orientation and food detection in three species of marine turtles.
- Creator
- Kedzuf, Stephanie C., Salmon, Michael, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
The cues used by marine turtles to locate foraging areas in the open ocean are largely unknown though some species (especially the green turtle [Chelonia mydas], the loggerhead [Caretta caretta], and the leatherback [Dermochelys coriacea]) somehow locate areas of high productivity. Loggerheads can detect airborne odors, but a capacity to orient has not yet been investigated. In this comparative study, tethered loggerheads and leatherbacks were exposed to dimethyl sulfide (DMS) or food odors...
Show moreThe cues used by marine turtles to locate foraging areas in the open ocean are largely unknown though some species (especially the green turtle [Chelonia mydas], the loggerhead [Caretta caretta], and the leatherback [Dermochelys coriacea]) somehow locate areas of high productivity. Loggerheads can detect airborne odors, but a capacity to orient has not yet been investigated. In this comparative study, tethered loggerheads and leatherbacks were exposed to dimethyl sulfide (DMS) or food odors in a laminar flow of air. Turtles did not orient into the air current. Free-swimming loggerheads and green turtles were also exposed to air- or waterborne food (squid) odor plus a neutral visual stimulus. Both species showed increases in swimming activity and biting behavior to both stimuli. These results suggest that airborne odors are likely not used to locate distant areas, but that they are used in localized food searching efforts.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004296
- Subject Headings
- Animal behavior, Animal orientation, Population genetics, Predation (Biology), Sea turtles -- Habitat, Sea turtles -- Life cycles, Wildlife conservation
- Format
- Document (PDF)
- Title
- Determining the sensitive period for magnetic imprinting in loggerhead turtles.
- Creator
- Pate, Jessica Hope, Salmon, Michael, Franquiz, Auriel, Graduate College
- Date Issued
- 2013-04-12
- PURL
- http://purl.flvc.org/fcla/dt/3361335
- Subject Headings
- Loggerhead turtle, Geomagnetism, Imprinting
- Format
- Document (PDF)
- Title
- Does allometric growth in juvenile marine turtles have survival benefits? A morphological test with a gape-limited predator.
- Creator
- Scholl, Joshua, Salmon, Michael
- Date Issued
- 2013-04-05
- PURL
- http://purl.flvc.org/fcla/dt/3361191
- Subject Headings
- Allometry, Marine turtles, Predators
- Format
- Document (PDF)
- Title
- Ecological correlates of the abundance of juvenile green sea turtles (Chelonia Mydas) on nearshore reefs in southeast Florida.
- Creator
- Stadler, Melanie, Salmon, Michael, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Juvenile green turtle (Chelonia mydas) abundance differs among nearshore reefs, but why some sites are preferred over others is unknown. My study had two objectives: to quantify differences in abundance over time (one year) and to determine what ecological factors were correlated with those differences. I conducted quarterly surveys on reefs in Palm Beach and Broward Counties and compared reef sites with respect to (i) water depth, (ii) algal abundance and composition, and (iii) changes in...
Show moreJuvenile green turtle (Chelonia mydas) abundance differs among nearshore reefs, but why some sites are preferred over others is unknown. My study had two objectives: to quantify differences in abundance over time (one year) and to determine what ecological factors were correlated with those differences. I conducted quarterly surveys on reefs in Palm Beach and Broward Counties and compared reef sites with respect to (i) water depth, (ii) algal abundance and composition, and (iii) changes in reef area (caused by sand covering) through time (11 years). Turtles were most abundant on shallow reefs exposed to high light levels that remained stable (uncovered by sand) for long periods of time. These reefs had the highest diversity of algal species, in part because cropping by the turtles prevented any one species from becoming dominant. My results suggest that both physical and biological factors make some reefs more attractive to turtles than others
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fau/fd/FA0004064
- Subject Headings
- Conservation biology -- Florida, Ecology -- Statistical methods, Sea turtles -- Ecology -- Florida, Wildlife conservation -- Florida
- Format
- Document (PDF)
- Title
- The hawksbill rookery at Antigua, W.I.: nest success, hatchling behavior, and hatchling survival during offshore migration.
- Creator
- Reising, Megan, Salmon, Michael, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
The younger life history stages of marine turtles (eggs, hatchlings) often fail to survive. To compensate, sea turtles nest several times/season and produce large clutches of eggs. The hawksbill produces the largest clutches (150 eggs) and the smallest hatchlings of any marine turtle. My study, done at Jumby Bay in Antigua, West Indies, was designed to determine whether they did so to compensate for loss in the nest, hatchling loss in the water, or both factors. I found that most of the eggs ...
Show moreThe younger life history stages of marine turtles (eggs, hatchlings) often fail to survive. To compensate, sea turtles nest several times/season and produce large clutches of eggs. The hawksbill produces the largest clutches (150 eggs) and the smallest hatchlings of any marine turtle. My study, done at Jumby Bay in Antigua, West Indies, was designed to determine whether they did so to compensate for loss in the nest, hatchling loss in the water, or both factors. I found that most of the eggs (79 %) survived to become hatchlings that left the nest and entered the sea. However, 88 % of the hatchlings swimming offshore were taken by predators within minutes after they began their migration. These results suggest that at Jumby Bay, large clutch size is favored in hawksbills because of predation pressures on the hatchlings.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fau/fd/FA0004049
- Subject Headings
- Animal migration -- Antigua -- Jumbo Bay, Animal orientation -- Antigua -- Jumbo Bay, Hawksbill turtle -- Research -- Antigua -- Jumbo Bay, Predation (Biology), Sea turtles -- Research -- Antigua -- Jumbo Bay, Wildlife conservation -- Antigua -- Jumbo Bay
- Format
- Document (PDF)
- Title
- Visual wavelength discrimination by the loggerhead turtle, Caretta caretta.
- Creator
- Young, Morgan, Salmon, Michael, Forward, Richard B., Jr., Graduate College
- Date Issued
- 2011-04-08
- PURL
- http://purl.flvc.org/fcla/dt/3164729
- Subject Headings
- Loggerhead turtle, Spectral sensitivity, Phototaxis
- Format
- Document (PDF)
- Title
- Activity and Habitat Selection by Loggerhead (Caretta caretta L.) and Green Turtle (Chelonia mydas. L.) Hatchlings: A Laboratory and Field Study.
- Creator
- Smith, Morgan M., Salmon, Michael, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Loggerhead and green turtle neonates migrate from Florida's coast during a 24-36 h frenzy. Post-frenzy loggerheads are often found in flotsam (Sargassum), while postfrenzy green turtles "disappear." This study compared the frenzy and post-frenzy activity of each species, their response to flotsam (in the laboratory and field), and the role of experience in habitat selection. Both species were most active during day I; activity thereafter declined (especially in loggerheads). Inactive...
Show moreLoggerhead and green turtle neonates migrate from Florida's coast during a 24-36 h frenzy. Post-frenzy loggerheads are often found in flotsam (Sargassum), while postfrenzy green turtles "disappear." This study compared the frenzy and post-frenzy activity of each species, their response to flotsam (in the laboratory and field), and the role of experience in habitat selection. Both species were most active during day I; activity thereafter declined (especially in loggerheads). Inactive loggerheads occupied Sargassum and open water (day or night) whereas inactive green turtles occupied Sargassum by day and both habitats at night. Exposure to Sargassum had no effect on the later habitat choices ofloggerheads, while exposed green turtles preferred Sargassum over plastic plants. In the field, both species preferred flotsam to open water, but occupied distinct microhabitats. Loggerheads preferred the mat surface while green turtles hid within the mat. Differences in activity and habitat selection likely reflect species-specific migratory and anti-predator strategies.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000832
- Subject Headings
- Sea turtles--Ecology--Case studies, Wildlife conservation--Case studies, Habitat partitioning (Ecology), Adaptation (Biology)
- Format
- Document (PDF)
- Title
- Do Fiddler Crab Larvae Show Phenotypic Plasticity?.
- Creator
- Christopher, Catherine E., Salmon, Michael, Florida Atlantic University
- Abstract/Description
-
Larval release by adult fiddler crabs occurs during the ebbing tides, but its timing relative to the day-night and tidal amplitude cycles depends upon tidal form (e.g., shows phenotypical plasticity). Crabs (Uca thayeri) from Florida's East Coast are exposed to semidiurnal tides and release their larvae at night, whereas crabs from Florida's West Coast exposed to mixed tides release their larvae during the afternoon. The purpose of this study was to determine whether the larvae could hatch at...
Show moreLarval release by adult fiddler crabs occurs during the ebbing tides, but its timing relative to the day-night and tidal amplitude cycles depends upon tidal form (e.g., shows phenotypical plasticity). Crabs (Uca thayeri) from Florida's East Coast are exposed to semidiurnal tides and release their larvae at night, whereas crabs from Florida's West Coast exposed to mixed tides release their larvae during the afternoon. The purpose of this study was to determine whether the larvae could hatch at times other than those correlated with the tidal form at their location. Clusters of eggs at similar stages of development, 24-72 h in advance of release, were reciprocally transferred between females from each coast. Release ofboth the transferred larvae and maternal clutch occurred synchronously, and at the time dictated by the female's tidal regime. These results suggest that larvae are phenotypically plastic with respect to hatching time and can either delay (West coast) or advance (East coast) their response to release signals from females.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000733
- Subject Headings
- Cell differentiation, Adaptation (Biology), Evolution (Biology), Phenotypic plasticity
- Format
- Document (PDF)
- Title
- Behavioral Responses of Leatherback Juveniles (Dermochelys coriacea L) to Lights Used in the Longline Fishery.
- Creator
- Gless, Jodie M., Salmon, Michael, Florida Atlantic University
- Abstract/Description
-
The pelagic longline fishery is responsible for significant mortality to sea turtles as a result of foul hooking, entanglement in the lines, and internal injury after consuming the baited hook. Bait, gear and lights (used to attract the target fishes to the baits at night) are three variables that could also attract sea turtles to the lines. This study tests the role of the lights in attracting leatherback (Dermochelys coriacea) turtles and compares their behavior to the loggerhead (Caretta...
Show moreThe pelagic longline fishery is responsible for significant mortality to sea turtles as a result of foul hooking, entanglement in the lines, and internal injury after consuming the baited hook. Bait, gear and lights (used to attract the target fishes to the baits at night) are three variables that could also attract sea turtles to the lines. This study tests the role of the lights in attracting leatherback (Dermochelys coriacea) turtles and compares their behavior to the loggerhead (Caretta carelta), shown in previous studies to orient toward both lightsticks and battery powered LEDs used in the fishery. The same lights were used in experiments done on leatherbacks reared at Florida Atlantic University's Marine Laboratory. The leatherbacks were exposed to the lights at night when they were between 5 and 42 days old. The results show that leatherbacks, unlike loggerheads, either do not orient toward the lights or orient away from them at an angle that enabled the turtles to keep the light in their peripheral field cf view. Thus, the capture of leatherbacks in longlines is probably a consequence of other factors (such as attraction to the odor of the baits, or to natural prey located near the Iines) that need to be investigated through future research. The results also show that efforts to reduce the incidental capture and injury of marine turtles in longlines must be based upon a firm understanding of the similarities, as well as the differences, between turtle species.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000763
- Subject Headings
- Longlining (Fisheries), Fishery management, Spectral sensitivity, Leatherback turtle--Research, Animal behavior
- Format
- Document (PDF)