B.J. Scharf1 and J.S. Strickland2
1 Marine Science Agent – UF/IFAS Extension Hernando County; 16110 Aviation Loop Drive, Brooksville, FL
2 County Extension Director and Agricultural Agent – UF/IFAS Extension Osceola County; 1921 Kissimmee Valley Ln, Kissimmee, FL
Situation: The Florida Fish and Wildlife Conservation Commission (FWC) uses airplanes to monitor Florida’s manatee population. Unfortunately, this sampling method is costly, limited to altitudes above 500 feet, and has resulted in data gaps along Florida’s Springs Coast. In response, we designed a method utilizing drones to efficiently improve manatee counts at a lower cost and from lower altitudes resulting in clearer images.
Methods: After reviewing FWC’s limited manatee data and conducting visual observations, we programmed a flight path within the Litchi app to fly a Phantom 4 Pro drone over our areas of interest. Three drone flights were conducted after major cold fronts had passed between December 2019 and March 2020 at an altitude of 150-250ft. Video was recorded and reviewed on a computer.
Results: Weather did not meet the threshold established by FWC for aerial surveys to be implemented between December 2019 and March 2020. However, FWC previously conducted 26 aerial surveys between 1995 and January 2019 and an average of 13 manatees were recorded per Hernando survey. When compared to FWC surveys, our average of 45 manatees per drone flight was statistically significant suggesting drones are an effective method for monitoring (t-test, p value of 0.0003). Due to the lower flight altitude, scars used for identification were clearly documented on most manatees observed during drone videos. Additionally, we were able to complete our drone surveys at a total estimated cost of $350. This is a cost savings of $2,337.50 when compared to conducting airplane surveys for the same area.
Conclusion: More manatees were counted by using drones and at a lower cost than airplane surveys. While we could not do a direct comparison to 2020 data, the average over a 24-year span was relatively smaller than what we found with drones the following year.