AGSO Cruise 125 Report : Tasmante Swath-mapping and Reflection Seismic Cruise off Tasmania using R.V. L'Atalante

The Tasmante cruise (AGSO Cruise 125) started in Auckland on 12 February 1994, and ended in Adelaide on 29 March 1994 (Fig. 1). The cruise used the French research vessel l'Atalante on an exchange basis. The French vessel was used rather than Rig Seismic because of the wide-angleswath-mapping capability of its SIMRAD EM12D system. Data were recorded on transits, as well as off Tasmania, our main area of interest (Figs. 1 & 2). The swath-mapping system functioned well throughout. The maps produced are mostly at 1:250 000 scale, and cover the transit from New Zealand (T1-77), the detailed survey off Tasmania (C1-C7), and the transit to Adelaide (T8-T9). The suite of maps generally includes ship tracks, sonar imagery, detailed and less detailed contour maps (25 and 50 m contours), and an overlay of sonar imagery on the less detailed contours. In addition, 1:1 000 000 scale maps of the entire Tasmanian survey area were produced of bathymetry (50 m contours) and imagery. Finally, 1:100 000 scale maps were provided of two fisheries areas off Tasmania: 20 m contours and imagery in thesouth, and 20 m contours in the west.