Single beam acoustic surveys in Ningaloo Marine Park, Western Australia (WAMSI Node 3 Project 1 Subproject 3.1.1)

In 2006, two areas in the Cloates Sanctuary Zone (SZ) (mid and north), one area in the Mandu SZ, one reference area outside the Cloates SZ and a reference area outside the Osprey SZ, in the Ningaloo Marine Park (NMP), were surveyed in transects, using a Simrad EQ60 Single beam echo-sounder, providing cross and along shelf profiles for each surveyed area.In 2007, surveys were extended from the southern boundary of the Ningaloo Marine Park at Red Bluff to south of Cloates SZ and from north of Mandu SZ to Point Murat. Preliminary onboard processing of single-beam acoustic backscatter data displayed differences in seabed acoustic roughness (irregularities in topography) and hardness (type of substrate) aiding in the identification of broad-scale habitats for sampling. The backscatter (Sv) values from the transect data were examined using Nearest Neighbour Interpolation within ArcGIS Spatial Analyst Tool. Future detailed analysis will aid in the preparation of marine habitat maps of the areas surveyed, and provide surrogate information for additional broad-scale biodiversity assessments. Surveys were undertaken to aid in the identification of any features of interest on the seafloor. Although this is a course method of acoustic survey, it is cost effective and provides a baseline bathymetry, which has not been achieved previously in Ningaloo Marine Park.