The distribution and some aspects of the ecology of Euphausia crystallorophias, Euphausia frigida, Euphausia triacantha and Thysanoessa macrura are presented. The investigations in the Polish Sector "A" show that E. triacantha is the northernmost and E. crystallorophias the southernmost species. These two species occurred least frequently. T. macrura was the most numerous and most regularly distributed species in the region under investigations.