Georeferenced photographs of benthic photoquadrats acquired over seven reefs in the Mackay to Capricorn region of the Great Barrier Reef, May, 2019

Underwater georeferenced photo-transect surveys were conducted at different locations: in the shallow waters of the Reef Flat (0.5-2.5m) by a snorkeller, or, along a 5m depth contour of the Reef Slope by a diver. For these surveys, the snorkellers or divers traversed a pre-determined transect 250-1000 m in length, while taking photos of the benthos at a set height using a standard digital camera and towing a surface float GPS which was logging its track every five seconds. The camera lens provided a 1.0 m x 1.0 m footprint, at 0.5 m height above the benthos. Horizontal distance between photoquadrats was estimated by fin kicks of the surveyor, and corresponded to a surface distance of approximately 2.0 - 4.0 m. […]