Characterisation of seafloor imagery from the Sabrina Coast continental shelf

A total of 701 still images were analysed from 10 transects on the Sabrina Coast continental shelf. Imagery was collected from the RVIB Nathaniel B Palmer (NBP 14-02, 29 January - 16 March 2014) across a greater than 3000 km2 area. A 'yoyo' camera, with downward facing digital still and video cameras mounted within a tubular steel frame, was deployed on a coaxial cable to image the seafloor. The Ocean Imaging Systems DSC 10000 digital still camera (10.2 megapixel, 20 mm, Nikon D-80 camera) was contained within titanium housing. Camera settings were: F-8, focus 1.9 m, ASA-400. An Ocean Imaging Systems 3831 Strobe (200 W-S) was positioned 1m from the camera at an angle of 26 degrees from vertical. A Model 494 bottom contact switch triggered the camera and strobe at 2.5m above the sea floor, imaging ~ 4.8m2 of sea floor. Parallel laser beams (10 cm separation) provided a reference scale for the images. Transects were conducted at a ship's speed of ~1 knot. Still images were characterised for main taxonomic groups and sediment properties based on the CATAMI scheme of Althaus et al. 2015.