The rocks from stomachs of Dissostichus mawsoni were used as a source of geological information about sea bottom. Authors suggest toothfish picks up stones from the bottom randomly, and these stones may be used for geological description of the closed areas of Antarctic shelf and slope. In this respect, Dissostichus mawsoni may be considered as a «dredge» with a wide area of sampling. Preliminary analyses allow qualitative estimation of geological structure of Antarctic shelf and continental slope in different areas.