THE STATE OF MAIN ORGANISMS OF PLANKTON C OMMUNITY IN THE BLACK-SEA IN 1993

Since the beginning of intensive development of Mnemiopsis leidyi in t he Black Sea, P.P. Shirshov Institute of Oceanology of Russian Academy of Sciences carried out regular observations of variability of the ma in planktonic organisms abundance in the Black Sea pelagic community. These observations were continued in 1993. The surveys were made two t imes - in August and November. Special attention was paid to five char acteristic points in the open sea, where monitoring study was carried out. The obtained results allow to consider that in 1993 the quantity of Mnemiopsis slightly increased compared with 1992, though its quanti ty was considerably lower than that during its development in 1989 - 1 990. Seasonal variability abundance of Mnemiopsis leidyi was unusual i n 1993: its biomass in August was much lower than in November. It indi cates that there is an interannual change of seasonal development of M nemiopsis population. It is significant that no any further decrease o f Calanus euxinus quantity was noticed.