During austral summer phytoplankton is the main component of food of E. superba postlarval stages. Diatomeae: Thalassiosira spp., Nitzschia spp. and tiny Pennatae constitue 98% of all consumed food particles. 91% of algae consumed were of 8—40 μm, and their mean size is 21.4 μm. The mean amount of algae found in of Euphausia superba was about 1700 per individual. The differences in species composition and the size of algae eaten by juvenes, preadult and adult individuals decrease the food competition between particular age groups of E. superba.