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- 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
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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
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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
- 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
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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
- 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
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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
- How leatherback hatchlings recognize their prey: Sensory predispositions and behavioral responses.
- Creator
- Constantino, Maricela Alcantara., Florida Atlantic University, Salmon, Michael
- Abstract/Description
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Leatherback sea turtles (Dermochelys coriacea) feed exclusively on gelatinous prey. Hatchlings are solitary and must possess a predisposition to respond to prey. In laboratory experiments, I studied the responses of nineteen leatherback hatchlings to visual (jellyfish model and shapes: circle, square, diamond) and chemical (homogenates of three prey) stimuli presented alone or as paired (visual + chemical) treatments once daily. When presented alone visual stimuli resembling jellyfish...
Show moreLeatherback sea turtles (Dermochelys coriacea) feed exclusively on gelatinous prey. Hatchlings are solitary and must possess a predisposition to respond to prey. In laboratory experiments, I studied the responses of nineteen leatherback hatchlings to visual (jellyfish model and shapes: circle, square, diamond) and chemical (homogenates of three prey) stimuli presented alone or as paired (visual + chemical) treatments once daily. When presented alone visual stimuli resembling jellyfish outlines elicited stronger feeding responses (changes in locomotion and orientation) than those not resembling jellyfish. Chemical stimuli alone induced a rheotaxis, but responses evoked by some homogenates were stronger than responses to others. Paired stimuli evoked stronger orientation and more consistent increases in swimming (flipper stroke) rate, indicating additive effects. Results suggest that both stimuli elicit food searching behavior and when they begin to forage, hatchlings already possess predispositions to respond to an adaptive array of prey shapes and odors.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12873
- Subject Headings
- Leatherback turtle, Predation (Biology)
- Format
- Document (PDF)
- Title
- Migratory Behavior of Hatchling Sea Turtles: Evidence for Population-Specific Divergence in the Loggerhead (Caretta caretta L.).
- Creator
- Madrak, Sheila Veronica, Salmon, Michael, Florida Atlantic University
- Abstract/Description
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Migratory bird and insect populations show differences in orientation direction, timing, and distances moved depending upon where they reside in relation to their migratory goals. These differences presumably occur because of selection for behavioral responses that promote the most efficient migratory strategies among members of each population. The purpose of this study was to determine whether migratory behavior in loggerhead hatchlings differs between populations that exit nesting beaches...
Show moreMigratory bird and insect populations show differences in orientation direction, timing, and distances moved depending upon where they reside in relation to their migratory goals. These differences presumably occur because of selection for behavioral responses that promote the most efficient migratory strategies among members of each population. The purpose of this study was to determine whether migratory behavior in loggerhead hatchlings differs between populations that exit nesting beaches on the East and West coast of Florida. When the turtles emerge from the nests, they initially show a swimming "frenzy" that serves to distance individuals from shallow coastal waters, displacing them toward oceanic currents that are used to transport the turtles to the North Atlantic Gyre. On the East coast of Florida, turtles swim eastward toward the Florida Current (western portion of the Gulf Stream) located relatively close to the shoreline (on average, 2 km offshore at Miami to 33 km offshore at Melbourne Beach). On the West coast of Florida, turtles swim westward toward the Loop Current in the Gulf of Mexico, which is located farther offshore (150 km offshore at St. Petersburg to over 200 km offshore at the Everglades National Park). In a previous study, we demonstrated that for East coast loggerheads, the frenzy consists of continuous swimming for - 24 h, followed over the next 5 days by postfrenzy (diurnal, with little nocturnal) swimming activity. No comparable data exist that characterize the frenzy period of loggerheads from the West coast ofFlorida. We used identical methods to quantify the migratory activity of hatchlings from the West coast of Florida. Hatchlings were captured as they emerged from nests located between Venice and Sarasota, Florida. They were then tethered in water-filled pools under laboratory conditions, where temperature and photoperiod could be controlled to duplicate conditions used when studying the East coast turtles. Activity was continuously recorded over the next six days. The data were analyzed to determine the proportion of time the turtles spent swimming every day, and the proportion of that swimming activity that occurred during the light and dark period of each day. Turtl~s from each coast showed no statistical difference in the proportion oftime spent swimming each day. However, after day 1, West coast hatchlings showed statistically lower levels of swimming activity during the day and statistically higher levels of swimming activity at night than did turtles from the East coast. We hypothesize that these differences may reflect a more diffuse period of active "searching" for appropriate oceanic currents by the West coast turtles, under conditions where greater predation pressures might select for more movement under conditions of darkness. Such a response may be appropriate when migratory goals are located at greater distances, and when turtles must migrate farther from the coast to reach deeper, and presumably less predator-rich, waters.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000792
- Subject Headings
- Animal migration--Florida, Sea turtles--Migration--Florida, Predation (Biology), Animal orientation--Florida
- Format
- Document (PDF)
