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Plasma Steroid Hormones in Loggerhead and Green Sea Turtle Hatchlings
Title
Plasma Steroid Hormones in Loggerhead and Green Sea Turtle Hatchlings.
Creator
Reis, Andrea, Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Florida’s sea turtle populations are increasing due to conservation efforts; however, sea turtle species are vulnerable to climate change. Turtles exhibit temperaturedependent sex determination, in which nest environment influences sex. Environmental changes may produce altered sex ratios that limit reproduction potential; therefore hatchling sex ratios should be monitored. Hatchlings are not externally sexually dimorphic, making sex identification difficult. This study established baseline...
Show moreFlorida’s sea turtle populations are increasing due to conservation efforts; however, sea turtle species are vulnerable to climate change. Turtles exhibit temperaturedependent sex determination, in which nest environment influences sex. Environmental changes may produce altered sex ratios that limit reproduction potential; therefore hatchling sex ratios should be monitored. Hatchlings are not externally sexually dimorphic, making sex identification difficult. This study established baseline plasma hormone concentrations in hatchling and post-hatchling green (Chelonia mydas) and loggerhead (Caretta caretta) sea turtles using High Performance Liquid Chromatography. Five hormones were assayed and were present in the majority of samples (testosterone: N.D.-10.12, progesterone: N.D.-0.43, estradiol: N.D.-4.78, estriol: N.D.-5.55 and estrone: N.D.-1.67 μg/mL). Plasma hormones did not distinguish hatchling sex because male and female ranges overlapped. Hormone concentrations varied with sex but also with incubation temperature, indicating that climate change could impact hatchling and posthatchling hormone profiles and thus could impact future fitness.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004626
Subject Headings
Sea turtles--Embryology., Sea turtles--Habitat--Conservation., Sex determination, Genetic., Loggerhead turtle--Effect of temperature on., Developmental genetics.
Format
Document (PDF)
Hatchling sex ratios and nest temperature-sex ratio response of three South Florida marine turtle species (Caretta caretta L., Chelona mydas L., and Dermochelys coriacea V.)
Title
Hatchling sex ratios and nest temperature-sex ratio response of three South Florida marine turtle species (Caretta caretta L., Chelona mydas L., and Dermochelys coriacea V.).
Creator
Rogers, Micah Marie., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
South Florida's loggerhead (Caretta caretta), green (Chelonia mydas) and leatherback (Dermochelys coriacea) sea turtles hatchling have environmentally determined sex. The in situ nest mean hatchling sex ratios (SR) were highly female-biased : loggerhead F=0.89) and green turtle F=0.81; leatherback's SR was nearly balanced (0.55F). Nest temperatures and SRs differed between leatherbacks and loggerhead and green turtles. The latter two did not differ. The loggerhead response parameters were...
Show moreSouth Florida's loggerhead (Caretta caretta), green (Chelonia mydas) and leatherback (Dermochelys coriacea) sea turtles hatchling have environmentally determined sex. The in situ nest mean hatchling sex ratios (SR) were highly female-biased : loggerhead F=0.89) and green turtle F=0.81; leatherback's SR was nearly balanced (0.55F). Nest temperatures and SRs differed between leatherbacks and loggerhead and green turtles. The latter two did not differ. The loggerhead response parameters were estimated within biological limitations by both 50-65% of incubation and mean middle 1/3 temperature. The maximum middle 1/3 temperature was the best-fit predictor for green turtles. No best-fit sex ratio-temperature response could be identified for leatherbacks. Clutches incubating under natural conditions can vary greatly in SR ; TRT differences may account for differences among species' sex ratios.
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Date Issued
2013
PURL
http://purl.flvc.org/fcla/dt/3361062
Subject Headings
Sex ratio, Sex determination, Genetic, Sea turtles, Nests, Sea turtles, Embryology, Loggerhead turtle, Nests, Loggerhead turtle, Effect of temperature on
Format
Document (PDF)
Predicting leatherback sea turtle sex ratios using spatial interpolation of nesting beach temperatures
Title
Predicting leatherback sea turtle sex ratios using spatial interpolation of nesting beach temperatures.
Creator
Weston, Emily G., Wyneken, Jeanette, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Sex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand...
Show moreSex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females will cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand temperatures from May- August and across the spatial range of leatherback nesting habitat. I spatially interpolated those temperatures to create maps that predicted temperatures for all nests incubating on SPWNR. Nest temperatures were also directly measured and compared with predicted nest temperatures to validate the prediction model. Sexes of dead-in-nest hatchlings and full term embryos were used to confirm the sex-temperature response. The model showed that microclimatic variation likely impacts the production of both sexes on SPNWR.
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Date Issued
2013
PURL
http://purl.flvc.org/fau/fd/FA0004071
Subject Headings
Leatherback turtle -- Habitat -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Loggerhead turtle -- Effect of temperature on, Sandy Point National Wildlife Refuge (United States Virgin Islands), Sea turtles -- Nests -- St. Croix -- Sandy Point National Wildlife Refuge (United States Virgin Islands), Sex determination, Genetic, Sex ratios, Vegetation dynamics
Format
Document (PDF)