Results on sea - water quality control and level of pollution in the coastal Southern Adriatic (Montenegro, Yugoslavia) were discussed from data collected in 1997. Investigations from Boka Kotorska Bay, coastal sea up to Bojana river mouth and in front of Bojana river mouth were presented separately. For above mentioned areas, basic hydrographic parameters, as well as the level of bacterial contamination were examined throughout the year (1996/1997 period). In Kotor Bay, which is the shallowest and exposed to the strongest land - based sources, as in the Tivat Bay, some changes influenced by anthropogenic eutrophication were already found.

In this paper, results of seasonal investigations throughout 2002, important for evaluation of the eutrophication and bacterial pollution of the Montenegrin coastal sea were presented. It was established that the difference between warmer and colder periods of the year was highest in the part of the Montenegrin coastal sea exposed to the strongest impact of the open waters of the Southern Adriatic.

Investigations of phytoplankton were done in the shallow Montenegrin coastal sea during the period from June to December, 2002. These investigations were the continuation from the preceding years. The main intention was to establish the impact of eutrophication to the quantity and composition of phytoplankton i.e. to establish the difference between areas in the bay and outside the bay. Like is previous years, the highest quantities of phytoplankton - microphytoplankton above all, were found in the area of the Boka Kotorska Bay (in Kotor Bay), Montenegro (Serbia&Montenegro). In July, 2.1 x 10**6 cells/cubic dm were found with dominant species Leptocylindrus minimus represented with 1.4 x 10**6 cells/cubic dm. In the area outside the Bay of Boka Kotorska, exposed to the impact of the open sea, values were significantly lower. In front of Budva, maximum was 1.7 x 10**5 cells/cubic dm in July. At locality exposed to the influence of the river Bojana (brackish water), similar values were established, except in October when 1.1 x 10**6 cells/cubic dm were found.

In this paper, there were discussed the results of ecological investigation of the Montenerin part of the Adriatic sea during the period 1996-2003. Evaluation of the sea-water quality was done in the coastal sea. The importance of multiannual ecological investigations was emphasized, too.

Investigations of phytoplankton in the Montenegrin coastal sea through summer (June, July, August) 2003 are described in this paper. They represent continuation from the previous years, and especially from 2001 and 2002. Maximum microphytoplankton quantity is found in the area of the bay (Kotor Bay) during June 3.9 x 10**6 cell/cubic dm, with the dominance of Nitzschia delicatissima (99%). This species was found with high percentage (more than 50%) during July and August, too. Leptocylindrus minimus and Skeletonema costatum, which were dominant in the previous period, through this year were slightly presented. In the area outside the Bay of Boka Kotorska, microphytoplankton was presented with quantities cell between 10**3 and 10**5 cell/cubic dm. Mean values of microphytoplankton in the area of the Boka Kotorska Bay were in 2003 year 4.6 times higher than outside the Bay. The same ratio was found for nanophytoplankton, too.