Thematic accuracy assessment of acoustic seabed data for shallow benthic habitat mapping

Abstract

A single beam acoustic ground discrimination system (AGDS) was used to survey 1.25 km² of shallow (< 20 m depth) seabed on the northeast coast of Tasmania, Australia. This paper investigates the uncertainties associated with the qualitative interpretation of real time and post‐processed acoustic signal, and the effect of track spacing on the mapping of rocky reef distribution. The survey was repeated with different track spacing (50 m, 100 m, 200 m and 50 × 200 m shore normal) to investigate the influence of data density and ‘knowledge based interpolation’ validated against direct measurements made with an underwater video camera. Habitat area calculations varied substantially only with the 50 × 200 m transect. These results have important implications for the qualitative assessment and application of AGDS technology in shallow water marine habitat mapping.

Keywords:

• Seabed habitat mapping
• Acoustic classification
• AGDS
• Accuracy assessment

Acknowledgements

The authors would like to acknowledge the Tasmanian Aquaculture and Fisheries Institute at the University of Tasmania for providing support and financial assistance for this research. The authors also gratefully acknowledge comments from one anonymous reviewer and Dr Toby Jarvis, Australian Antarctic Division. These comments greatly improved this paper.