Zooplankton in Plovdiv Area, Now and a Quarter Century Ago

The subject of the present study was the zooplankton complex in the fishery ponds of Institute of Fisheries and Aquaculture, Plovdiv for the period 1993 - 1995 and 2012, 2015, 2016. The composition of the communities was mainly of the crustacean type. Over the years, a trend has been found towards reduction in the number of taxa. There are signs of increased eutrophication of these pools, which we believe are due to their prolonged operation, and there are no significant differences between the two analyzed periods based on the Shannon and Pielou indices and the Sladecek Sample Index.