Current Search: Salmon, Michael (x)
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- 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
- 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
- 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
- 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
- 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
- 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
- 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
- Ecological correlates of the abundance of juvenile green sea turtles (Chelonia mydas) on nearshore reefs in southeast Florida.
- Creator
- Stadler, Melanie, Salmon, Michael, Roberts, Charles, Graduate College
- Date Issued
- 2013-04-12
- PURL
- http://purl.flvc.org/fcla/dt/3361359
- Subject Headings
- Green turtle, Chelonia mydas, Reefs--Florida
- 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
-
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
- Effects on beach renourishment on the survival of loggerhead sea turtles.
- Creator
- Broadwell, Ann L., Florida Atlantic University, Salmon, Michael
- Abstract/Description
-
The fate of loggerhead (Caretta caretta, L.) clutches at four physically different beaches, including a renourished site, was investigated in the Boca Raton area. I compared the four sites with regard to their thermal environment, moisture content, sand grain size, and pore spacing at depths of a typical nest. Significantly more sea turtle hatchlings emerged from nests deposited on the renourished beach than at the other sites. At the renourished beach moisture content and pore spacing were...
Show moreThe fate of loggerhead (Caretta caretta, L.) clutches at four physically different beaches, including a renourished site, was investigated in the Boca Raton area. I compared the four sites with regard to their thermal environment, moisture content, sand grain size, and pore spacing at depths of a typical nest. Significantly more sea turtle hatchlings emerged from nests deposited on the renourished beach than at the other sites. At the renourished beach moisture content and pore spacing were highest. Pore spacing and moisture content correlated negatively with the number of hatchlings which died in the nest, and correlated positively with emergence success. At the natural beach, hatchling weight was lowest and straight-line carapace length (SLC) was shortest. I conclude that at the renourished beach, conditions favored hatchling production. However, that may not be the case in all instances of renourishment, as effects probably vary with the nature of the sands used to replenish the beach.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14749
- Subject Headings
- Loggerhead turtle--Reproduction, Loggerhead turtle--Florida
- 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
- Do embedded roadway lights protect sea turtles?.
- Creator
- Bertolotti, Lesley L., Florida Atlantic University, Salmon, Michael
- Abstract/Description
-
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
- 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)
- Title
- Entrainment of larval release in an intertidal crab ( Uca thayeri) after exposure to a different tidal regime: Testing the "plasticity" hypothesis.
- Creator
- Weaver, Ann, Florida Atlantic University, Salmon, Michael
- Abstract/Description
-
Endogenous rhythms allow most organisms to synchronize their behavior and physiology with physical cycles that vary on a daily, lunar or annual cycle. Populations within species often show variation in the timing of functionally identical rhythms. This variation occurs because physical cycles may differ with geography. The purpose of this study was to determine whether hatching rhythms shown by fiddler crabs (Genus Uca) on one coastline could be entrained by the different tide patterns...
Show moreEndogenous rhythms allow most organisms to synchronize their behavior and physiology with physical cycles that vary on a daily, lunar or annual cycle. Populations within species often show variation in the timing of functionally identical rhythms. This variation occurs because physical cycles may differ with geography. The purpose of this study was to determine whether hatching rhythms shown by fiddler crabs (Genus Uca) on one coastline could be entrained by the different tide patterns present at another coastline. To test this I transferred breeding females (Uca thayeri) from mangroves on the west coast of Florida to mangroves on the east coast. On the west coast, females are exposed to "mixed" tides; most release their larvae during the day or night (early summer), or during the day (mid- to late summer). On the east coast, females are exposed to "semidiurnal" tides; they release their larvae between dusk and midnight. After four weeks of exposure to the East Coast tides, crabs from the West Coast showed hatching rhythms identical to the resident crabs. This change indicates that the crabs show behavioral (phenotypic) "plasticity". These observations provide further evidence for the adaptive value of behavioral plasticity.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/15774
- Subject Headings
- Fiddler crabs--Eggs, Fiddler crabs--Adaptation, Biological rhythms
- Format
- Document (PDF)
- Title
- Home range and movements of juvenile Atlantic green turtles (Chelonia mydas L.) on shallow reef habitats in Palm Beach, Florida, United States of America.
- Creator
- Makowski, Christopher, Florida Atlantic University, Salmon, Michael
- Abstract/Description
-
This study's objectives were to determine if coastal (shallow-water, oceanic reef) aggregations of juvenile green turtles (Chelonia mydas L.) in Palm Beach, Florida occupied distinct home ranges and how these home ranges compared in size and resource availability with those studied elsewhere. Six immature green turtles were captured, measured, and subjected to esophageal lavage to determine diet. Each turtle was returned to its initial capture site within 24 h with an ultrasonic transmitter...
Show moreThis study's objectives were to determine if coastal (shallow-water, oceanic reef) aggregations of juvenile green turtles (Chelonia mydas L.) in Palm Beach, Florida occupied distinct home ranges and how these home ranges compared in size and resource availability with those studied elsewhere. Six immature green turtles were captured, measured, and subjected to esophageal lavage to determine diet. Each turtle was returned to its initial capture site within 24 h with an ultrasonic transmitter used to track movements. All turtles were <65 cm SCL, had ingested similar macroalgae, and occupied markedly small home ranges (mean = 2.38 +/- 1.78 km 2), largely restricted to the reef itself. Diving and feeding activity peaked during the day; at night, activity was minimal. The food and sleeping site resource distribution at this specific location coincides with the turtles' home range size and shape, with considerable overlap of core areas.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fcla/dt/13160
- Subject Headings
- Sea turtles--Florida--Palm Beach, Animal behavior, Wildlife conservation, Green turtle--Florida--Palm Beach
- 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
-
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
- Nest caging as a sea turtle management strategy: Do the benefits outweigh the costs on urban beaches?.
- Creator
- Adamany, Stephanie Lynne., Florida Atlantic University, Salmon, Michael
- Abstract/Description
-
Caging of sea turtle nests has used by City of Boca Raton's sea turtle conservation program to deter terrestrial predators and reduce human disturbance. The juxtaposition of nest cages and artificial lighting may pose serious threats to hatchlings. I addressed possible negative effects of cages on sea turtle hatchlings' seafinding abilities and potential "cage-trapping" under natural and artificially illuminated conditions. Cages did not effect hatchling orientation on artificially...
Show moreCaging of sea turtle nests has used by City of Boca Raton's sea turtle conservation program to deter terrestrial predators and reduce human disturbance. The juxtaposition of nest cages and artificial lighting may pose serious threats to hatchlings. I addressed possible negative effects of cages on sea turtle hatchlings' seafinding abilities and potential "cage-trapping" under natural and artificially illuminated conditions. Cages did not effect hatchling orientation on artificially illuminated or dark beaches. Hatchlings did not experience any delay in cage escape on dark beaches, but a significant number were trapped inside the cages on artificially illuminated beaches. The highest incidence of trapping occurred on nights surrounding a new moon. Disoriented hatchlings exited cages either after city lighting was reduced (past midnight) or as natural levels of illumination increased shortly before sunrise. When cages were darkened all turtles escaped but many still exhibited signs of disorientation.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15312
- Subject Headings
- Sea turtles--Florida, Sea turtles--Nests
- Format
- Document (PDF)
- Title
- Seafinding orientation of hatchlings exposed to filtered lighting: Effects of varying beach conditions.
- Creator
- Tuxbury, Susan Mary., Florida Atlantic University, Salmon, Michael
- Abstract/Description
-
Under normal conditions, hatchling sea turtles crawl toward the ocean but streetlights placed on coastal roadways can attract the turtles toward land. Two light filters were designed to exclude the shorter light wavelengths most attractive to turtles. I did laboratory tests to determine if green turtle and loggerhead hatchlings oriented normally ("seaward") in the presence of filtered lighting. Light passed through either filter (#2422 acrylic and NLW) attracted the turtles unless coastal...
Show moreUnder normal conditions, hatchling sea turtles crawl toward the ocean but streetlights placed on coastal roadways can attract the turtles toward land. Two light filters were designed to exclude the shorter light wavelengths most attractive to turtles. I did laboratory tests to determine if green turtle and loggerhead hatchlings oriented normally ("seaward") in the presence of filtered lighting. Light passed through either filter (#2422 acrylic and NLW) attracted the turtles unless coastal cues (an elevated horizon) were strong or background (full moon) illumination was present. Green turtles and loggerheads responded differently to the same filters, indicating that neither filter provided adequate protection for both species. I conclude that these filters fail to protect the turtles. Conventional forms of light control (shielding and/or lowering light fixtures, decreasing wattage, or turning off problem lights) remain the best way to shield turtles from the harmful effects of artificial lighting.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12804
- Subject Headings
- Sea turtles, Light pollution
- Format
- Document (PDF)
- Title
- Visual spectral sensitivity of loggerhead (Caretta caretta L.) and leatherback (Dermochelys coriacea L.) hatchlings: A comparative study.
- Creator
- Gocke, Judith P., Florida Atlantic University, Salmon, Michael
- Abstract/Description
-
In the ocean, lighting varies with habitat; the eye's spectral sensitivity must vary with visual ecology. Green turtles are the only sea turtle whose spectral sensitivity has been studied. Loggerheads and leatherbacks see visible light between 340 and 700 nm. However, the wavelengths detected with the greatest sensitivity by both species are those best transmitted at the specific depths where food, mates and predators are likely to be encountered. Both species have trichromatic vision, but...
Show moreIn the ocean, lighting varies with habitat; the eye's spectral sensitivity must vary with visual ecology. Green turtles are the only sea turtle whose spectral sensitivity has been studied. Loggerheads and leatherbacks see visible light between 340 and 700 nm. However, the wavelengths detected with the greatest sensitivity by both species are those best transmitted at the specific depths where food, mates and predators are likely to be encountered. Both species have trichromatic vision, but the species differ in the concentration and peak sensitivity of each visual pigment resulting in either a broadly tuned (loggerhead) or finely tuned (leatherback) spectral sensitivity. Spectral sensitivity of leatherbacks overlaps both bioluminescence of prey, and light available in clear, deep, oceanic waters.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13029
- Subject Headings
- Loggerhead turtle, Leatherback turtle, Spectral sensitivity
- Format
- Document (PDF)