Side scan sonar acoustic surveys in Ningaloo Marine Park, Western Australia (WAMSI Node 3 Project 1 Subproject 3.1.1)

The Klein Side Scan Sonar system is used in a wide variety of underwater search, survey, and engineering applications. These systems employ acoustic energy and electronics to create a continuous graphical record of the sea floor surface topography. The graphical record produced by this system approximates an aerial photograph of the sea floor surface. Klein System 3000 side scan sonar surveys were concentrated between the areas of Gnarloo and Red Bluff and were conducted in two parts. The first part of the survey covered a total swath area of 21,871,725.4m2 and a total track line length of 117,861.1m parallel to the coast from Red Bluff to Gnaraloo. The second part of the survey covered a total swath area of 11,979,623.5m2 and a total track line length of 70,108m and ran perpendicular to the coast in two areas in between Red Bluff and Gnaraloo. The objective of the acoustic survey was to test its capabilities for mapping the seafloor in the deep waters of Ningaloo Marine Park and determine the textural differences in the seafloor, which in turn correlate to particular benthic habitats. The different textures (habitats) could then be groundtruthed to confirm the correlations between textures and habitat type/benthos. A Sub-Bottom Profiler was not used in this survey but could compliment any future acoustic survey by providing information about the thickness of the sedimentary veneer present in any given location and how the characteristics of this veneer affectscolonisation of benthos and its ability to sustain itself in any given place. A profiler of this type may also provide information about the changes occurring temporally and spatially in sediments overlying the limestone base of the slope. Initial set-up and testing of the Klein system was completed close to Exmouth at the Muiron Island Marine Management Area. The unit and technician were hired from Seismic Asia Pacific Pty Ltd.