Grant: 23-039R
Project Title: Late-Season Sea Turtle Nesting in Central and South Brevard County, Florida, Year 3
Project Manager: Erin E. Seney, Ph.D.
Organization: University of Central Florida (Research and Educational Institute)
Grant Amount: $14,631.00
Completion Date: 2024-08-24
Summary: The University of Central Florida Marine Turtle Research Group (UCF MTRG) monitors sea turtle activity on densely-nested beaches, including the northern 21.0 km (13.0 miles) of the Archie Carr National Wildlife Refuge. These beaches support about 1 in 6 loggerhead (Caretta caretta) nests and 1 in 3 green turtle (Chelonia mydas) nests laid in the state, and UCF marks about 750-1,100 nests annually. Loggerhead nesting in UCF's survey region typically extends into September, whereas green turtle nesting continues into October-November. Both species' nests typically incubate for about 50-55 days on UCF beaches, but durations vary with temperature and precipitation. These late-season nests are most likely to overlap with dune restoration and beach nourishment. In Brevard County, sand placement activities typically occur during November-March, with some projects extending into spring. Per its marine turtle handbook, the FWC recognizes that late-season nest data are limited and takes a precautionary approach with relocation and inventory schedules. Larger, more recently collected datasets for late-season nests will help managers set appropriate avoidance marking and relocation windows based on the species' biology, as well as inform other seasonal beach restrictions and nest inventory protocols. We will increase the number of September-November nests marked, monitored, and inventoried by the UCF MTRG and deploy temperature data loggers in 2023 to measure nest and ambient sand temperatures. Collecting temperature data will allow us to better understand incubation duration and reproductive success of nests laid in the cooler fall and winter months and provide insight into lower temperature limits tolerated by late-season nests, which will help fill knowledge gaps to better inform management agencies.
Results: The UCF MTRG conducted daily surveys on the Brevard County Mid Reach, South Reach, and Archie Carr National Wildlife Refuge (ACNWR), as part of contracted (non-STGP) beach monitoring, as well as biweekly surveys on Patrick Space Force Base, during September-October 2023. Under 23-039R, we marked 32 loggerhead nests during 21 August-30 September (8 nests in September) and 44 green turtle nests during 1 September-31 October in excess of our regular, contracted marking scheme. September-October program-wide marking totals were 8 loggerhead and 55 green turtle nests. Thus, "extra" marking funded by 23-039R represented 100% of loggerhead and 80% of green turtle nests marked in these months. Through 31 October, 3% of the MTRG's total 2023 loggerhead nest marking was comprised of nests laid during September, and 10% of the 2023 green turtle nest marking was completed during September-October. HOBO MX2201 temperature data loggers were deployed in and next to 40 green turtle nests throughout the 2023 season (2 per nest site). Data loggers were deployed at 10 green turtle nests in June, 10 in July, 9 in August, 8 in September, and 3 in October (29 main-season, 11 late-season). Monitoring and nest assessments concluded in January 2024. Nests marked late August-September were heavily impacted by sand accretion. Nests incubating after September experienced high tides and erosion, causing full washouts of 1 loggerhead and 2 green turtle nests