Current Search: Chelonia mydas (x)
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- Title
- PREVALENCE AND SEVERITY OF FIBROPAPILLOMATOSIS IN JUVENILE GREEN TURTLES (CHELONIA MYDAS) IN THREE HABITATS ON FLORIDA'S EAST COAST.
- Creator
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Borrowman, Kelly, Fauth, John, University of Central Florida
- Abstract / Description
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Fibropapillomatosis (FP) is a tumor-forming disease mainly found in juvenile green turtles (Chelonia mydas) inhabiting Florida's east coast. Despite increased research on the herpes virus that putatively causes it, long-term assessment is still needed of the distribution and severity of FP. Using the decades-long database compiled by the University of Central Florida Marine Turtle Research Group, I determined FP severity and distribution at three different sites: Indian River Lagoon (IRL),...
Show moreFibropapillomatosis (FP) is a tumor-forming disease mainly found in juvenile green turtles (Chelonia mydas) inhabiting Florida's east coast. Despite increased research on the herpes virus that putatively causes it, long-term assessment is still needed of the distribution and severity of FP. Using the decades-long database compiled by the University of Central Florida Marine Turtle Research Group, I determined FP severity and distribution at three different sites: Indian River Lagoon (IRL), Sabellariid Worm Reef (SWR) and Trident Submarine Basin (TSB). Fibropapillomatosis occurred in >50% of IRL turtles, 18% of SWR turtles and <1% of TSB turtles. Regression of FP tumors was correlated with its prevalence, i.e. when and where FP was common, tumor regression was common. The probability of a turtle being non-afflicted or mildly afflicted increased with both increasing straight-line carapace length (SCL) and increasing relative body condition (residuals of log body mass versus log SCL). Mean annual growth rates of IRL and SWR turtles did not vary with FP severity; however, mean annual growth rates in IRL (1.10 cm/y) were significantly higher than in SWR (1.05 cm/y) and TSB (1.04 cm/y). Annual apparent survival estimates for IRL and TSB turtles were 0.72 and 0.73, respectively, and were constant over time. Even with increased prevalence of FP, annual apparent survival estimates were constant and similar to survival estimates of juvenile green turtles in areas without FP. In IRL, survival rates among FP Categories 0, 1 and 2 were similar (0.74, 0.74 and 0.81 respectively) and lower only for FP Category 3 (0.63). Thus, while FP occurred in >50% of turtles in some Florida east coast populations, their annual apparent survival only declined in advanced cases (FP Category 3). These data suggest 1) FP afflicts smaller or younger turtles, 2) larger juveniles, sub-adults and adults are either non-afflicted or possibly recover from this disease, and 3) annual apparent survival rates of green turtle populations are independent of FP prevalence except when tumor growth is extreme.
Show less - Date Issued
- 2008
- Identifier
- CFE0002250, ucf:47853
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002250
- Title
- Sex ratios of juvenile green turtles (Chelonia mydas) in three developmental habitats along the east coast of Florida.
- Creator
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Sanchez, Cheryl, Weishampel, John, Ehrhart, Llewellyn, VonHolle, Mary, Wibbels, Thane, University of Central Florida
- Abstract / Description
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The concept of temperature dependent sex determination (TSD) has been somewhat of anevolutionary enigma for many decades and has had increased attention with the growingpredictions of a changing climate, particularly in species that are already threatened or endangered. TSD taxa of concern include marine turtles, which go through various life stages covering a range of regions. This, in turn, creates difficulties in addressing basic demographic questions. Secondary sex ratios (from life...
Show moreThe concept of temperature dependent sex determination (TSD) has been somewhat of anevolutionary enigma for many decades and has had increased attention with the growingpredictions of a changing climate, particularly in species that are already threatened or endangered. TSD taxa of concern include marine turtles, which go through various life stages covering a range of regions. This, in turn, creates difficulties in addressing basic demographic questions. Secondary sex ratios (from life stages post-hatchling) were investigated by capturing juvenile green turtles (Chelonia mydas), 22.6-60.9 cm in straight carapace length (SCL), from three developmental areas along the east coast of Florida (a region known to have important juvenile aggregations) by analyzing circulating testosterone levels. All three aggregations exhibited significant female biases with an overall ratio of 3.2:1 (female: male). The probability of a turtle being female increased as the size of the individual decreased. Ratios obtained in this study were slightly less female-biased, but not significantly different, than those observed in the late 1990s. However, they were significantly more biased than those found in a late 1980s pilot study. The shift to significantly female-biased ratios may be beneficial to a recovering population, an evolutionary adaptation, and is common among juvenile aggregations. A more skewed female bias in smaller size classes may be indicative of recent, warmer periods during incubation on the nesting beaches. This female bias could become more exaggerated if temperatures meet future climate warming predictions.
Show less - Date Issued
- 2013
- Identifier
- CFE0004747, ucf:49771
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004747
- Title
- JUVENILE GREEN TURTLE (CHELONIA MYDAS) FORAGING ECOLOGY:FEEDING SELECTIVITY AND FORAGE NUTRIENT ANALYSIS.
- Creator
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Gilbert, Eliza, Ehrhart, Llewellyn, University of Central Florida
- Abstract / Description
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For the endangered green turtle, Chelonia mydas, a fundamental component of recovery and conservation is an understanding of its foraging ecology. Foraging optimality models suggest animals will select resources of high quality over those of low quality. For green turtles, this behavior is important, as sufficient quantities of nutritionally adequate forage items are necessary for growth and reproduction. One intrinsic element in the understanding of green turtle foraging ecology is to...
Show moreFor the endangered green turtle, Chelonia mydas, a fundamental component of recovery and conservation is an understanding of its foraging ecology. Foraging optimality models suggest animals will select resources of high quality over those of low quality. For green turtles, this behavior is important, as sufficient quantities of nutritionally adequate forage items are necessary for growth and reproduction. One intrinsic element in the understanding of green turtle foraging ecology is to identify and document the availability and quality of forage resources preferred by green turtles. The objectives of this study were: 1) determine whether juvenile green turtles showed a feeding preference by comparing prey items in the diet to the availability of those items in the habitat, 2) identify species for which there was selection or avoidance, 3) identify nutritional factors determining selection or avoidance of prey items, and 4) evaluate the nutritional content of the diet. This research was conducted by comparing lavage samples from juvenile green turtles to samples from benthic surveys within the habitat. To determine feeding preference, Ivlev's Electivity Index was used to compare ingested species of algae with those available in the habitat. Nutritional analysis of forage was conducted to identify possible nutrients relating to feeding preference. Juvenile green turtles selectively foraged on Chlorophyta and Rhodophyta. Results indicate that diet selection was based on nutritional content. Both the composite diet and the main diet item, Hypnea spp, had a higher gross energy value, were higher in protein, and lower in fiber than prey items that were avoided. Conservation of green turtles requires effective habitat management, which must be informed by an understanding and evaluation of the habitat. For juvenile green turtles, this study indicates that habitats dominated by Chlorophyta and Rhodophyta may be more important for the health of green turtle populations than habitats dominated by Phaeophyta.
Show less - Date Issued
- 2005
- Identifier
- CFE0000487, ucf:46355
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000487
