This voyage provides an opportunity to test and refine optimal techniques to map and assess seabed habitat developed in a previous CMR project (NOO OP2000-SE02). Importantly, this voyage will use the National Facility's high-resolution EM300 swath mapper for its first program of biological and physical habitat mapping. The sampling locations are a number of submarine canyons and their immediately adjacent flanks on the west coast of Tasmania and east of Bass Strait. These are prime targets for our methods development because each canyon area is characterised by a great variety of seabed topography and benthic communities concentrated in a relatively small area (< 300 sq km). This voyage is also an opportunity to apply the data collected to marine resource management planning in the South East Region. Submarine canyons represent a type of habitat unit ("Level 3 biogeomorphic units") having a strong influence on the location of offshore Marine Protected Areas on the continental slope and rise, and many are likely to be biodiversity "hotspots". Several canyons are also the locations of the largest known aggregations of feeding and spawning fishes in the South-East Fishery region, and these support a range of intense, increasing and, in places, conflicting fishing activities. Given the immediate and increasing relevance of submarine canyons to conservation and fishery managers, it is then surprising to realize that virtually all those in the SE region remain unsampled by scientists, and are named only by commercial fishers. For these reasons, sampling on this voyage will focus on the "Big Horseshoe Canyon" mapped previously with the EM1002 and EM12 swath instruments (to enable comparison of data types, and to investigate temporal persistence of features), and several "new" areas. Sediment samples were taken for analysis by Geoscience Australia.

The scientific objectives for the survey were split across two voyages (SS07/2005 for leg 1 and SS10/2005 for leg 2). The first leg was to map and visually survey (video) the upper continental slope (and at selected sites transects from the outer shelf to the mid-slope) at regular intervals of 1 deg latitude; the second leg was to targeted sample the surveyed locations to document the benthic biodiversity. Sediment samples were divided into two samples: an elutrition sample for macroinvertebrates that was sent to Robin Wilson at MV for analysis and a sediment sample to be analysed by Geoscience Australia.

The overall aims were to provide data on the distribution of deep seabed habitats and fauna that are amenable to scientific hypothesis testing, can be immediately applied to marine resource management processes, and that enable strategic development of tools and techniques for understanding the processes that maintain deep sea biodiversity. This work was to support the process of NWR Estate inventory and management performance assessment by providing interpreted benthic habitat maps, faunal inventories, distribution maps and conservation values. Data will be collected at scientific reference sites from potential MPA areas that can be re-visited for monitoring purposes in the future. Sampling along environmental gradients (geographic range and depth) in this section of Australia's coast will also provide the opportunity to evaluate biogeographic hypotheses. Further refinement of predictive methods for identifying seabed habitat types, initially developed in temperate and cool-temperate environments, will be enabled by data collection from this tropical location in Australia. We intended to highlight the importance of this underlying science as a modern "Voyage of Discovery" given the likely significance of the findings in terms of Australia's biodiversity and its biogeography and evolution. (From Voyage Plan). Sediment samples were divided into two samples: an elutrition sample for macroinvertebrates that was sent to Robin Wilson at MV for analysis and a sediment sample to be analysed by Geoscience Australia.

This is the CSIRO portion of the collaborative Tasmanian Aquaculture and Fisheries Institute, University of Tasmania (TAFI)/CSIRO Marine Research Project titled 'Understanding Shelf-break Habitat for Sustainable Management of Fisheries with Spatial Overlap', which aimed to map and understand shelf-break seabed habitats (~150-350m depths) around Tasmania, Australia, which is an area of interaction between two fishery sectors, giant crab trappers and finfish trawlers. Both of these have been expanding over the past decade, with potential of impact to target species abundance, habitat structure, and ecosystem structure. This project aimed to research the habitat effects of these activities over the period 2003-2005 through sampling of fished and unfished areas using video transects, multi-beam acoustic swath mapping, and collection of physical samples using sediment grabs and benthic sleds, using chartered vessels and a voyage of the National Facility FRV Southern Surveyor in 2004. Specific objectives for the giant crab (Pseudocarcinas gigas) habitat survey are as follows: - define and map giant crab habitat on the shelf edge, at several key locations off the Tasmanian east and west coasts; - detail distribution of giant crabs in relation to habitat features; - evaluate ecosystem links between habitats; - evaluate the vulnerability of habitat to damage by fishing (trawls and pots); and - evaluate the ability to obtain fishery independent information by video on the abundance, sex ratio, condition and size of giant crabs. The CSIRO portion of the work comprised a series of four surveys to assess the seabed habitats of the giant crab at the edge of the continental shelf around Tasmania. The image annotations collected for this project have been added to the Oracle data base BHIMAGE and the associated videos and still images have been archived as described in MarLIN record 14436 'Benthic Habitats Video Image Archive'.