Using Drone Imagery to Map Intertidal Oyster Reefs along Florida’s Gulf of Mexico Coast

Eastern oyster (Crassostrea virginica) reefs offer vital ecosystem services and support economically and culturally important fisheries. However, environmental and anthropogenic stressors have led to significant decline in oyster reef coverage globally and locally in places like the Suwannee Sound in Florida, USA. Current monitoring methods are insufficient for timely and accurate assessment of oyster resources in the region. Here we demonstrate how drone imagery can be used to delineate intertidal oyster reef coverage rapidly and reliably. The high spatial resolution offered by drone imagery enables accurate delineations. We use a segmentation algorithm to delineate reefs, which produces consistently detailed outlines that are more representative of reef morphology than manual delineations. In total, 1,394 reefs were delineated, which corresponds with 497, 670 m2 of reef area. Of the delineated reefs, 236 (17%) were newly mapped, aligning with 19,848 m2 of newly mapped intertidal oyster reef habitat. The overlapping drone imagery also enabled the production of digital surface models, which were used to calculate volume to area ratio as an indicator of reef condition. These delineations and features serve as accurate baseline data that can be compared to future surveys to monitor how reefs are changing over time in the Suwannee Sound. These methods can also be expanded to other geographical areas and can aid in identifying early signs of decline in oyster reefs.