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SEA TURTLE GENETICS PROJECT 2025

“Creating important information concerning the behavior of native to Hunting Island Loggerhead Sea Turtle mothers and all others”.

Capturing the necessary information requires the ongoing gathering of nest-based DNA by the Hunting Island and many other Southeast Atlantic Coast turtle teams and then the analysis of the genetic data by Senior Scientist Brian Shamblin of University of Georgia’s Warnell School of Forestry and Natural Resources.  

Key information from what the data analysis tells us is, if sea turtles are returning to their birthplace to lay their eggs, how many times in their laying season they return to their birthplace, where else (islands and beaches) they lay their eggs in South Carolina or contiguous states, and what is typical number of eggs they lay in their nests.  

This information is critically important to the Hunting Island Turtle Conservation Team because it gives them a profile of each of the sea turtles who are visiting Hunting Island to lay their eggs.  In addition, a summary of the turtle profile activity will indicate whether or not Hunting Island is attracting a respectable number of its native sea turtles to return for egg laying.  Added to this vital information is detail on whether or not Hunting Island is increasing or decreasing its percentage of South Carolina sea turtle nests.  It is quite obvious that an increasing percentage of SC nests for Hunting Island is a welcome trend, however a decreasing percentage should be a “red flag” to the Turtle Team who should inform HISP management that the island is losing its attractiveness to mother sea turtles and that action should be considered to reverse this trend e.g. more extensive dune fencing, a higher priory for beach renourishement, etc. 

Just like a well maintained Caretta vehicle and a FAA licensed drone are the necessary “hard costs” for an effective Turtle Conservation Program, there are equally important “soft costs” which include a comprehensive Mother Sea Turtle data collection and analysis effort which I have summarized.  Friends of Hunting Island is proud to have  contributed to this very important piece of the Hunting Island Sea Turtle Conservation effort to ensure its continuation.

The South Carolina Department of Natural Resources Marine Turtle Conservation Program is participating in a multi‐state project along with Georgia and North Carolina to answer several basic loggerhead sea turtle nesting questions. The answers to these questions will help biologists better understand how the loggerhead population is doing. Currently, the actual number of loggerhead sea turtles that nest in South Carolina is not known. By collecting an egg from every single nest, we will use DNA genetic fingerprinting (CSI for sea turtles) to identify individual loggerhead nesting females. This information will provide a census of the actual nesting population. In addition to estimating how many females are nesting in South Carolina each year, we also have the potential to answer the following questions:

            • How many clutches of eggs does each nesting female lay in a year?

            • Is the female nesting on more than one beach?

            • How far apart are her nests?

            • How many turtles are nesting in more than one state?

            • Most individual females do not nest every year. How often does each                         turtle nest: every two years, three years, four more years?

            • How precisely does a daughter return to her hatching site to lay her eggs        

            • For more specific information, please visit:                         

 

Warnell School of Forestry and Natural Resources

Shamblin Lab

 

Demographics and population dynamics of Northern Recovery Unit loggerhead turtles via genetic tagging

 

 

 

 

 

 

 

 

In 2005, an astute technician on Little Cumberland Island, Georgia had the foresight to freeze eggshells from a depredated loggerhead turtle (Caretta caretta) nest where the nesting female had evaded detection and ask whether we could match it to their tagged females. Thus, the idea of getting tagging (using clutch sampling and microsatellite genotyping as a means of identifying individuals without the need to physically intercept them) was “hatched.” Following pilot study testing in 2006, we began genetic tagging statewide in Georgia in 2008. Subpopulation-wide sampling encompassing the Northern Recovery Unit nesting habitats in Georgia, South Carolina, North Carolina, Virginia, and Maryland commenced in 2010. A few counties in northeastern Florida were added in 2016 to provide resighting data. 

 

To date, this project has identified over 13,000 unique nesting females. We are using the individual nesting history data to address several questions related to the demographics and population dynamics of this subpopulation. This work would not be possible without tremendous staff support of the state sea turtle programs and enthusiastic participation of more than 90 nesting survey projects conducted by NGO groups as well as volunteers and staff representing municipal, state and federal agencies that cover approximately 1,000 km of beaches from Florida to Maryland. 

Friends of Hunting Island

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