The distribution, size composition, sex ratio and sexual maturity of Dissostichus eleginoides and D. mawsoni from BANZARE Bank were investigated using biological data collected by a Japanese commercial fishing vessel during the austral summer fishing seasons (December–February) from 2006/07 to 2008/09. Dissostichus eleginoides was mainly caught on shallower banks (<1 000 m), while D. mawsoni was caught on deeper slopes (>1 500 m). Separation of the two species by depth may be related to physical intolerance to cooler temperatures because of the lack of antifreeze in the former species. Dissostichus eleginoides showed a resting stage in sexual maturity, while D. mawsoni was in developing condition. In D. mawsoni, small fish contributed a very low proportion to abundance, suggesting that no substantial recruitment takes place on BANZARE Bank and the populations consist primarily of adults migrating from adjacent Antarctic coastal areas. The life cycle of D. mawsoni on BANZARE Bank is similar to that hypothesised for the Ross Sea population with analogous latitudinal patterns in sexual maturity and size composition. The study indicates that the management of Dissostichus spp. on BANZARE Bank and adjacent waters needs to consider species-specific distribution and possible migration.