In order to determine the dynamic of biomass of stoneworts from Lake Ohrid as a function of the trophic state of the water, we collected samples from four different localities. The localities Sveti Stefan and Mazija, were characterized by oligotrophic state of the water, while the other two Grasnica and Daljan were characterized by eutrophic-mezotrophic water quality. The stoneworts samples were taken from 4-5 different depths from each investigated locality. The results of our investigations have shown that higher trophic level of the water from the littoral region of the localities Grasnica and Daljan (especially in the points of inflow of river Grasnica and Daljan) decreases the amount in stoneworts biomass compared with the biomass of stoneworts collected from the first two localities that characterizes oligotrophic character of the water.

In order to protect the water current of the river Tisza, the fermentation industry AD "Fermin" Senta, Serbia (Serbia&Montenegro) has built the biological waste water treatment plant for the waste water discharged from the yeasts producing factory, which started the production in 1982. So far the output of the plant can be definied as not equal to the designed capacity level. The results of four effect analyses have been shown in the tabelar survey as well as the technological block scheme of both the current and suggested solution projects. The suggested solution basically contains phase separation in anaerobic procedure and the intraduction of tertial treatment method (nitrification and denitrification). The paper presents a contribution to optimal technology of industrial waste water treatment.

In this paper are presented investigation of cyprinid fish spawning grounds in Lake Ohrid. Keeping the optimum population condition of particular fish species is possibly only if we care to study and sustain fish spawning grounds.

TesToks, version 1.0 is the specialized software developed for the toxicity tests data analysis. The paper presents, in short, the options and the constrains of the software.

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.

The results of the regular water quality monitoring in the river Moraca (Montenegro, Serbia&Montenegro), are presented in this paper. Thirty samples have been processed from six measuring station along the river's flow. The data relevant quality indicators (conductivity, dissolved oxygen, chemical oxygen demand, five days biochemical oxygen demand, ammonia, nitrites, nitrates, and phosphates) have been processed in the light of the existing regulations. It has been confirmed that the water quality, from the physical-chemical aspect, varies depending on the measuring location and the hydrological situation. The evaluated condition shows that the water quality gets worse, in the period of the five years, on the profiles of downstream places from Podgorica. The level of decrease gets to deviation from the requested A2CII class. It is particularly shown in the changes of the values for the nutrients and the relevant indicators of the organic pollution (dissolved oxygen, five days biochemical oxygen demand, chemical oxygen demand), which we presume can be consequence of the effect of the algaes during the period of the "low level water".

The activities acid, neutral and alkaline phosphatases, as well as total phosphatases activities were estimated in the water of the Lake Ohrid tributaries Sateska, Koselska, Velgoska and Cherava. The same analyses were performed in the littoral zones where the tribitaries enter Lake Ohrid. The study covers the period from September 2000 to October 2001. The obtained results show that different types of phosphatase effect different extracellular activities, an observation which is probably the result of differences in the location within the cells and the way of intracellular synthesis.

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.

During the parasitological investigations on the gills of 3 cyprinid species from Lake Dojran (the Former Yugoslav Republic of Macedonia), are found 4 monogenean species: in Rutilus rutilus dojranensis are found Dactylogyrus similis and Dactylogyrus suecicus, in Scardinius erythrophthalmus dojranensis is found Dactylogyrus difformis, and in Alburnus alburnus macedonicus is found Ligophorus sp. Prevalence in Rutilus alburnus dojranensis is 40.46%, in Scardinius erythrophthalmus dojranensis is 55.56%, and in Alburnus alburnus macedonicus is the lowest and amounts 2.02%. All monogenean species represents the first record for parasitic fauna of fish species in the Former Yugoslav Republic of Macedonia. Finding of Ligophorus sp. in the fishes of the family Cyprinidae is new to science generally.

Concentrations of nitrate above defined levels for portable water are present in most of the groundwater sources in Velika Morava river alluvion. Some problems exists in Meminac and Kljuc, groundwater sources of Pozarevac town. Some detail investigations were organized in 2002. Survey of groundwater quality in the wide surrounding of Kljuc confirmed some earlier made assumptions about influence of agriculture and sewage water, and their contribution to existing groundwater quality.