Natal beach contributions to a southeastern United States subadult loggerhead sea turtle (Caretta caretta) feeding assemblage

Loggerhead sea turtles are a cherished natural treasure, especially along the Southeastern US coastline where they nest and feed. Although protected under the Endangered Species Act, their existence still balances precariously. The South Carolina Department of Natural Resources (SCDNR) conducts annual in-water surveys of a subadult feeding aggregation stretching a length of coast spanning Cape Hatteras, North Carolina to St. Augustine, Florida. Along with biometric data, blood samples were taken for genetic analysis. Utilizing polymerase chain reaction (PCR) amplification and sequencing, mitochondrial DNA (mtDNA) haplotypes were determined for all 927 individuals included from the 9-year study. An AMOVA and mixed stock analysis were conducted for each of the sample years to identify temporal variation in natal beach contributions to the subadult feeding assemblage. Female sea turtles return to their natal beaches to nest, a phenomenon known as "natal homing." This scenario allows for a unique opportunity to define natal beaches by specific mtDNA (maternally inherited) haplotype frequencies.;Haplotypic diversity did not alter significantly between sample years (Fst=0.001, p>0.1). Within year variation accounted for 99.89% of the total variation while between year variations only accounted for the remaining 0.11%. The South Florida and Northeast Florida-North Carolina nesting beach regions were consistently the greatest contributors to the feeding aggregate. Preliminary analyses indicate females outnumbered males in all of the samples years by at least a 2:1 ratio except in 2003. Among males, the NEFL-NC region was consistently the greatest contributor while amongst females, South Florida proved to be the largest source. Due to the long lifespan of sea turtles, nine years may not be a lengthy enough study period to identify any temporal variation and further investigation is recommended.