IMOS - AUV SIRIUS, CAMPAIGN: SCOTT REEF, JULY 2009

AUV Sirius (IMOS Platform code: SIRIUS) was deployed in tScott Reef in July 2009.

Scott Reef, WA (Heyward, Cooper, Radford, Colquhoun ‐ AIMS): The primary objective of work completed in July/August 2009 was to describe biological assemblages associated with deep coral reef systems at Scott Reef in WA. A significant proportion of South Scott Reef and the adjacent lagoon lies in waters between 30 m to 70 m deep that support a range of habitats similar to many of the submerged shoal systems strung along the edge of the continental shelf in the Timor Sea. The South Scott Reef lagoon covers 300 km^2 and is the largest area of this type observed on a single reef system in the NW region. Understanding the nature and dynamics of these deeper water areas will not only better describe the true extent of Australia’s tropical reef resources, but will contribute to a broader understanding of the overall resilience of coral reefs in the NW region. In order to produce an accurate, high resolution habitat map of the deeper reef waters and to establish viable deep water monitoring sites, high resolution acoustic mapping using digital mulitbeam from Geoscience Australia was completed in parallel with collecting georeferenced seabed images using the AUV Sirius and the existing AIMS towed video with high resolution stills systems. AUV deployments consisted of 19 dives over 12 days of operation onboard the R/V Solander using a mix of survey designs and illustrated the vehicle's reliability and versatility as a complementary habitat characterisation tool. On several occasions the vehicle operated beyond tracking range of the supporting vessel for extended periods facilitating the execution of other scientific objectives, particularly swath bathymetric mapping of the Scott Reef lagoon.