In the present paper it is presented application of Daily Egg Production Method (DEPM) to the anchovy (Engraulis encrasicolus L. 1758) stock in the open part of Montenegrin coast. This article is based on the research done within the frame of AdriaMed Project.

New locations for the distribution of algae C. corniculata (Phaeophyceae) are presented, with a scope to improve scarce knowledge on phytobenthos of the Montenegrian coast. In the Bay of Boka Kotorska this algae is found on 10 locations and on 3 locations, on depth of 3 m and 5 m, measurements of wet weight and length of primary branches are done. Differences between biomass of algae are note between different depths and different seasons, but between different locations there are no significant differences.

The paper shows available water resources potential of karsts spring waters of Carpatho-Balkan region of east Serbia. Basic elements of water balance are also given, as well as quantitative indicators of low flows. Karsts spring yield is compared to the domicile waters of Serbia. We can also read certain comments and see an estimation maximum usage of these karsts waters.

This work shows the effects of opening the Itebej sluice gate on the metals content of the water and sediment of the Begej canal. A deterioration in water quality resulted, in particular on the first day after opening of the sluice gate, when high concentrations of Zn, Cr, Cu and Pb were detected. The metals content of the surface sediments across the canal at Klek had significantly higher concentrations of Pb, Cr, Zn, Cu and Hg five days after the opening, whereas there were no obvious changes at Itebej. From the metals content of the suspended sediment it can be concluded that the increase in metals contents occurred one day after opening the sluice gate.

Water quality conditions of the Tatarnica canal are considered in this paper. Tatarnica is also the main canal of Begec drainage system, which is situated about twenty kilometers from Novi Sad on the west. Water quality of this canal is important, beside others, because its inflow into Danube is near Begecka Jama, which is representative of natural garden with special ecological asset. Results of investigation on this locality during three years are analyzed and presented. According the most relevant water quality parameters from predominant number of samples, water belongs to required category. Sometimes, a bad water quality are recognized, usually when organic pollution was appear, which influence higher value of BOD5.

Jegricka water body is part of the Main Drainage Channel System. The whole length of Jegricka (65 km, catchment surface 60.380 ha) is located in south part of Backa, Vojvodina Province. This highly modified water flow has become protected area since 2005 due to its specific natural features - diversity and uniqueness of biotic features, especially for birds and plants. In July 2008 survey of freshwater macroinvertebrates was conducted in order to assess water quality and conservation potential according to biotic characteristics according to conservation criteria within SERCON (System for Evaluating Rivers for Conservation) method. The aim of this paper was to evaluate the importance of macroinvertebrates as indicators of conservation potential of Jegricka water using SERCON. Results of analyses of species composition of freshwater invertebrates fauna showed presence of 12 higher taxonomic groups. Within these groups, 23 families were present at eight RHS river sections along investigated part of Jegricka water body. Togheter with SERCON based conservation criteria for macroinvertebrate, two types of biotic indices Biological Monitoring Working Party (BMWP) and Average Score Per Taxon (ASPT) were calculated in order to assess water quality. Results of the survey showed that Jegricka water body belongs probably to moderately polluted water type according to biotic indices. Results of conservation criteria Naturaless showed that observed and expected faunas are similar. Low values of SERCON family richness criteria based on whole length of water body indicate that Jegricka has low conservation potential, and that adequate rehabilitation measures should be considered in the future.

During the period of 2004-2005 ichthyological research on natural waters of Bardaca wetland (Bosnia and Herzegovina) was carried out and the occurrence of 24 fish species was recorded. On the basis of the occurrence and abundance of fish species indicators as limnosaprobic parameter, water quality of the analyzed watercourses (rivers Matura and Brzaja) was found to be beta mesosaprobic (the 2nd class of bonity) with saprobic index 2.02 for Marura River and 2.03 for Brzaja River. The obtained results indicate that water quality of this part Bardaca wetland was on satisfactory level for multiple purposes (as a source of water for Bardaca fishpond and in order to sustain ichthyofauna diversity and production.

The allochthonous aquatic macroinvertebrates and fish species represent a potential danger to the autochthonous diversity. Hydrobiological research conducted during 2008 under the development of medium-term programmes for fishery improvement in Serbia, showed that some of the allochthonous aquatic macroinvertebrates and fish species have expanded their areals to a new water habitats. Artificial lakes (reservoirs) proved to be very suitable for the population of allochthonous species, where they become numerous most of the time. New habitats were found for allochthonous aquatic macroinvertebrates species: shells (Dreissena polymorpha, Sinanodonta woodiana) and American crab (Orconectes limosus), and for fish species for Micropterus salmoides. It was also determined that fish populating is a good way to inhabit and expand new habitats with allochthonous species of aquatic organisms.

In the paper we presented the effort to collect the recent data clarifying eutrophication as one of the commonest problems of freshwater. The paper includes experience of researchers related to causes of onset and effects of eutrophicational processes on trophic level increase in reservoirs.

Environment is subject of changes in the presence of aquatic pollutants which increase synthesis of biotransformation enzymes and elicitate oxidative stress in aquatic organisms. Monitoring changes of quality of aquatic ecosystems could be based on watching certain biomarkers, like biochemical, molecular and physiological responses of aquatic organisms after exposure to organic toxicants.