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(1 - 6 of 6)
- Title
- Comparison of growth patterns in three species of juvenile sea turtles.
- Creator
- Pate, Jessica Hope, Salmon, Michael, Wyneken, Jeanette, Graduate College
- Abstract/Description
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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
- 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
- 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
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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
- 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
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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
- 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
- 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)
