During the Last Glaciation Maximum, at ca. 18 ka BP, both the Weddell and the Ross Gyres as well as near-coastal circulations probably lost their importance in the maintenance of Antarctic krill populations due to cooling of the water column and development of multi-year sea ice. Within the Antarctic Circumpolar Current at that time, some smaller-scale circulations related to islands and seamounts could have played a major role in controlling krill distribution.