Drones offer more efficient way to survey vital oyster reefs

Skimming 100 feet above the Gulf waters at 13 miles per hour and blasting out 700,000 laser pulses every second, a drone flies over this oyster reef off the Big Bend coast of western Florida in early 2021. A few minutes later, the drone lands on shore and, with a little computer magic back at the lab, spits out what the drone operators want to know: How are these reefs doing?

Oyster reefs across the Gulf and Atlantic coasts of the U.S.—vital providers of food, jobs, habitat, shore protection and water purification—are facing steep declines from overharvesting and environmental stressors. But spotting which reefs are at risk of collapse in time to intervene using conventional methods can be labor intensive and impractical.

Enter the drone.

"In the time it takes a person to measure just one or two square meters of reef, you can survey the entire reef structure with a drone," said Michael Espriella, a postdoctoral researcher at the University of Florida.

New research by Espriella and his UF colleagues shows that the digital elevation map produced by drone-based lidar—which pushes out rapid laser pulses that can measure distance—can accurately determine the condition of an oyster reef with much less time and labor than old-fashioned manual surveys.