SS2004/04 - Testing, refinement and application of methodology for optimised seabed mapping : Sediment samples

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.