EN
The zooplankton of a meromictic lake, in a former limestone quarry situated in southern Poland, was studied monthly in the years 2000-2001. A low density and diversity of zooplankton assemblage was noted. Individuals of the dominant species Daphnia longispina represented all body size classes and were present during the whole study period; the maximum number of Daphnia females carrying the eggs was noted in May. The normal dial vertical migration of Daphnia, studied in June, was observed.