Green turtle density in St. Joseph Bay, Florida, USA estimated by performing aerial surveys in 2016, 2017, and 2019

Green turtle (Chelonia mydas) density was estimated by performing aerial surveys with a DJI Phantom 3 Professional unmanned aerial vehicle (UAV). UAV systems have been found to provide an effective method for monitoring abundance when conducting daytime surveys of large marine organisms in coastal waters. Aerial surveys are an effective survey method for estimating sea turtle abundance because the method allows coverage of their extensive range. Because primary C. mydas foraging times are during the early morning and late afternoon throughout most of its range, transects were flown in the morning to enhance the reliability of estimates. Efforts were focused on the dense turtlegrass beds in the southern portion of the bay, as acoustic telemetry in St. Joseph Bay suggests that green turtles spend most of their time in this area. Aerial surveys were conducted over two surveys in 2019 during August and September and compared to surveys conducted previously in 2016 and 2017.