The South Carolina Department of Natural Resources in partnership with the UGA Marine Extension Service/Sea Grant recently concluded a 21-year (2000 to 2021), NMFS-funded sea turtle research trawl that captured >2,500 loggerhead turtles in the central South Atlantic Bight (SAB). Capture location coupled with lesser amounts of recapture/re-sighting data and telemetry tracks support annual fidelity to the survey area. Demographically, only 15% of captured loggerhead sea turtles were considered adults based on published size-at-age data, but genetic haplotypes indicate regional origin in relative proximity to foraging grounds and nearly three times as many females as males. Independent of size, less than 5% of tagged loggerhead sea turtles were recaptured following release but occurred up to 15 years later, consistent with high annual survival rates required for population stability. Unfortunately, given only four nighttime tagging projects across the Northern Recovery Unit (NRU) subpopulation and only slightly more for the larger Peninsula Recovery Unit (PRU) in Florida, there are few opportunities to physically recapture these individuals that will likely nest in this region eventually. This suggestion is supported by the re-sighting of two formerly juvenile loggerhead sea turtles captured in the trawl survey on PRU and NRU nesting beaches 13 to 14 years later, respectively. Therefore, in 2020 we initiated a pilot study to use genotype data to search for additional instances of recruitment into the adult segment of this population, for which a decade of nesting beach reference data exists for the NRU. Any “hits” from this close-kin mark-recapture approach to identify first order relatives (i.e., siblings and parent-offspring pairs) will provide valuable temporal and spatial context on the recruitment process in a study system where juveniles have been historically been under represented due to logistical constraints.

Satellite tracks have indicated that most loggerhead turtles nesting on Northern Recovery Unit beaches have foraging home ranges in the Mid-Atlantic Bight, South Atlantic Bight, or in the Subtropical Northwest Atlantic. However, the expense and logistics of satellite telemetry limits sample sizes and sampling locations. Our partners have developed techniques to assign nesting females to these three major foraging areas using the stable isotope signatures derived from skin or egg yolks. We’re incorporating these foraging ground assignments into demographic analyses to test whether and how foraging site choice affects reproduction.