Grant: 21-019R
Project Title: Connecting Sea Turtle Health and Ecology on the Archie Carr National Wildlife Refuge
Project Manager: Kate Mansfield
Organization: University of Central Florida (Research and Educational Institute)
Grant Amount: $12,152.00
Completion Date: 2024-01-31
Summary: The University of Central Florida Marine Turtle Group will focus on the health and ecology of loggerhead and green sea turtles nesting on the Archie Carr National Wildlife Refuge, Melbourne Beach, Florida as a component of a larger project which aims to evaluate the interface between health and ecology for these species across life-stages and habitats. These analyses will provide a better understanding of how environmental factors affect sea turtle health. This project will foster a collaboration with a previous Sea Turtle License Plate grant recipient, Dr. Simona Ceriani, by incorporating loggerhead foraging location (based on stable isotope analysis and satellite telemetry) into our environmental data. Additionally, baseline values identified and compared will be shared with local rehabilitation facilities (e.g., Brevard Zoo Sea Turtle Healing Center) to increase knowledge based on wild populations.
Results: Sample collection from nesting loggerheads was completed in August 2021 (n=122) and nesting green turtles in August 2022 (n=120). Collection of nest inventory data to be used as a habitat-specific parameter (Task 4), was completed by the end of each respective nesting season. Of the turtles with viable blood samples, 104 loggerhead (85%) and 93 green turtles (78%) also have successful inventory data. Missing inventory data can be the result of nests being washed out during high tide or storm events, depredations, or not being able to find the clutch after emergence. Stable isotope values for turtle foraging assignments were provided by our collaborator Dr. Simona Ceriani. For the loggerhead turtles, geographic assignments for likely foraging areas were conducted using the procedure described in Ceriani et al. (2023) and were available for 70 turtles with viable blood samples (57%). Similar models are in progress for green turtles, so raw isotopic values can be used in lieu of likely foraging areas. Plasma biochemistry analyses were completed for 51 adult loggerhead samples (42%) and the panel included Aspartate Aminotransferase (AST), Calcium, Glucose, Phosphorous, Uric Acid, Sodium, and Blood Urea Nitrogen (BUN). Hematocrit values (Packed Cell Values, PCV) were successfully determined for each sample collected and resulted in an average of 26.6% for loggerheads (range 17-38%) and 29.6% for green turtles (range 19-41%). The average loggerhead PCV was lower than literature values (32-40%) but was within the established range (18-54%) (Stacy & Innis 2017, Casal et al. 2009, Deem et al. 2009). Green turtle average PCV was within the established literature average (34.5% (22-52%)(Stacy & Innis 2017, Samour et al. 1998). Loggerhead plasma biochemistry analytes were all within literature ranges, but AST and Phosphorus averages for this population were higher than literature averages, and Sodium and BUN averages were lower. Preliminary linear regression models indicate significant relationships between female glucose levels and hatching success in loggerhead turtles. Neither species showed a significant trend for PCV values and hatching success. Further analyses will be explored using WBC differentiations, plasma protein values, and green turtle isotopic values.