Based on all available data a review of introduced non-indigenous species is reported for the area of Montenegrian coastal sea (South-East Adriatic Sea). All together 11 species were recorded, three algae and eight animals. Monitoring of invasive species has been done partially only for Caulerpa racemose var. cylindracea, while for other species distribution and impact on autochthonous environment is unknown.

The red algae Womersleyella setacea is Indo-Pacific species but introduced to Mediterranean Sea were is now relatively widely distributed. During research of benthic communities in Ponta Veslo locality (Lusnica peninsula, Montenegrian coast, Adriatic sea) in summer 2007 dense assemblages on rocky substratum and on sea grass Posidonia oceanica (L.) Del. rhizomes were discovered. The impact on biocenosis structure is discussed.

Research of phytoplankton is conducted in different seasons during 2004 and 2005. River Bojana and Ada Bojana are analyzed on several locations. The objective of research is based on algae as reliable indicator of water quality and ecological condition of water. We would like to show the need for protection of these water ecosystems from permanent contamination, basically sewage waste. Saprobiotic index is determined by Gulyas Pal method. Pantle Buck method is used to calculate saprobiotic level. Chlorophyll A is analyzed by spectrophotometer. Presence of Cyanophytae was established.

The puddles Novo Ilje 1 and Novo Ilje 2 are aquatic ecosystems periodically filled with moderate salt and alkaline water. In 2003 and 2004 quantitative analysis show the Euglenophyta domination. Trachelomonas taxa are the most common. The algae in planktonic communities are the most numerous in both puddles in researched years.

The puddles Slatina and Pecena Slatina are the old meanders of the river Tamis. These ecosystems are periodicity fill with moderate salt and high alkaline water. The paper gives a review of qualitative and quantitative analysis of the algal compositions. Cyanoprokaryota and Euglenophyta are more common. All investigated parameters like compositions of lagal communities, their abundace, biomass and chlorphyll-a showed a high level of nature eutriphication in these ecosystems.

In this paper the results of the application of WQI method on Vojvodina main rivers and canals are shown. There were investigated 41 localities, from April 2002 to May 2003. There was observed high degree of correlation between the WQI values and the qualitative composition of the desmid community. Exceptions to that rule were noticed, since that WQI is not sufficient parameter of the water quality.