During the analyses of zooplankton and hydrography samples from continuous field research in monthly series during 2002 on three shallow stations (Orahovac, Morinj and near the Institute) and 4 central stations in Boka Kotorska Bay (Adriatic sea, Montenegro (Serbia&Montenegro)), exceptionally dense populations of Penilia avirostris were observed. Presence of this species in refreshed waters during the summer in other parts of Adriatic and Mediterranean, and its designation as an indicator, are reasons for presentation of these gathered results from yearly cycle in Boka Kotorska Bay.

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.

Available data on zooplakton research in Adriatic sea show that coastal and open waters of south Adriatic are the zone of most available and richest area in Adriatic sea. Shallow waters along the shore and the Boka Kotorska Bay are characterized by a monotony of faunistic content, while, by contrast, high values of biomass are caused by abundance of a small number of estuary-neritic species. Open waters of South Adriatic are characterized by holoplankton, while waters of Boka Kotorska Bay are characterized by meroplankton. Zooplankton of open sea shows a high diversity of fauna but a small biomass in part of open water above the geatest depths, and significantly high values of biomass in epipelagic waters above the continental shelf.

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.

This work presents a short review of the existing situation, nature conditions and recognised facts which are important for the sea- pollution of the oil, and another kind of the spill ship oils, inside of the Boka Bay and in the area of the open Adriatic Sea. The proposed original and innovative action concerns the large scale application of a new technique for a cleaning up waterborne oil spills, based on the magnetic separation method by using the material "CleanMag", an oleophillic, and porous material which also is magnetic with an increased density lower than that of the water.

There are presented the results of investigations carried out in the Kotor Bay (Adriatic Sea), Montenegro (Serbia and Montenegro) during the winter months of 2004. The highest value of microphytoplankton as a greater size-fraction of phytoplankton is found in the surface layer during March (1.4 x 10**7 cells/cubic dm). The main edificator was diatomic species Skeletonema costatum with relative percentage about 100%. Obtained results point out that Kotor Bay belongs to the highest eutrophic or extreme eutrophic area. Similar result is found in the same period twenty years ago.

Eutrophicationn problems in the Kotor bay were studied monthly from September 2003 to August 2004. As a result of nutrient enrichment (directly dependent on human activities), phytoplankton growth was very intensive, reflected by high concentration of chlorophyll a (7.46 mg/cubic m).

In this paper, we used similarity index, such as Sorensen similarity index (S), Jaccard similarity index (Cj) and Percentage Similarity Index (PSC), to show similarities and contrasts within the qualitative structure of zooplankton of various bays within Boka Kotorska. This kind of statistical overview was made for Boka Kotorska Bay for the first time, so we believe that it is a valuable contribution to recent studies on zooplankton. Tables show the results for each index individually, as well as the smallest and greatest similarity among the bays. We also presented the number of recorded species in the Boka Kotorska Bay arranged by months for three different years.

The paper presents the seasonal overview of horizontal distribution and abundance for the species of genus Oithona in Bokokotorski Bay. Three species have been recorded. Oithona helgolandica and Oithona plumifera have a wide horizontal distribution within the Adriatic Sea, while Oithona nana is a typical euritherm and eurihaline form that occupies shallow and closed coastal areas along the eastern coast of Adriatic. Also presented are seasonal oscillations and quantitative presence of these species in the Copepoda population during 2002.

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.