p. 175 - 181 COMPARATIVE ZOOBENTHOS INVESTIGATIONS IN THE HISTRIA AND NUNTASI LAKES DURING THE PERIOD 1971-1976 Carol G. Nagy Romanian Marine Research Institute Constanta Abstract Zoobenthic investigations were carried out in 1971-1976 in the oligohaline lakes Histria and Nuntasi, at Romanian Black Sea coast. A brief descriptions are given of the different indicator systems used in evaluating trophic status. A method is performed for calculating abundancy index for Chironomidae populations. Based on the correlation between the quotients obtained for the phytoplank- tonic indicators and the results furnished by the Chironomids, it was showed that Histria remained mesotrophic while Nuntasi became eutrophic during the last decade.