Data on the distribution, abundance and population structure of krill in the Prydz Bay area during January–February 1985 are considered in relation to hydrography and phytoplankton standing stocks. Stratified mean density and biomass estimated for the whole surveyed area from RMT-8 hauls were among the lowest recorded (3.3 individuals 1000 m−3 and 3.1 g 1000 m−3) confirming Prydz Bay as a low krill abundance area in the Southern Ocean. Age cohorts 1+ to 4+ were present, the size of the animals increased from south to north and juveniles were mostly found in surface waters near the pack-ice. Adults were in an active reproductive phase: 98% of the females were mated and 35% were ready to spawn whereas 86% of the males carried spermatophores. Breeding was taking place in oceanic waters over deep zones with the spawning season limited to January-April. Phytoplankton biomass was also very low in the area (mean of 29 mg Chl a m−2 in the upper 200 m) and currents speed low, never reaching 10 cm s−1. Krill distribution was strongly related to water circulation pattern but not related to phytoplankton distribution.