The hydrochemistry of mountain lakes is highly conditioned by the chemicalcomposition of atmospheric deposition and by climate characteristics. Consequently these ecosystems have proved to be sensitive to long-term changes in both factors. Climate warming seems to be particularly pronounced in the Alpine region. A reduction of snow cover in space and time, due to less precipitation and higher temperatures, means a greater exposure of rocks and soils in the watersheds, which enhances weathering processes. In this paper we aim to evaluate the possible effect of these processes on long-term changes in the chemistry of alpine lakes. Recent climate changes affecting the study area were investigated through a data series referring to temperature, precipitation, snow depth and duration at some stations in the Ossola Valley. Chemical data of 35 lakes located in the Ossola and Sesia Valleys (Central Alps) were used. Lakes were sampled both in the late summer of 2000 and 2001 in the framework of two European Projects and the results compared with previous data (1984–1987). Two lakes (Boden Superiore and Inferiore, 2343 and 2334 m a.s.l., respectively), located in the northern part of the study area, have been sampled more or less continuously since the late 70s, enabling us to evaluate the trends of the main chemical variables. For lakes lying in catchments with highly soluble rocks, a comparison between the two data sets shows an increase of solute contents in the last few years. This result could be attributed to increased weathering rates due to climate warming.

Fourteen species of wild growing mushrooms and surface (0–10 cm) soils were collected near Lake Wdzydze in the northern part of Poland in 1996–1997 to understand the status of mercury pollution. Concentrations of mercury in mushrooms varied between 100±30 and 2400±1900 ng g⁻¹dry matter in caps and 60±1 and 1300±1500 ng g⁻¹dry matter in stalks. Concentrations of mercury in underlying soil were between 30±1 and 140±120 ng g⁻¹dry matter (between 36±18 and 63±100 ng g⁻¹depending on the soil type). Bioconcentration factors (BCF: concentrations in mushroom/concentrationin soil) of total mercury were between 2.3±1.1 and 90±110 for caps, and between 2.1±1.0 and 53±56 for stalks. Scaly tooth (Sarcodon imbricatum) contained the greatest concentrations of mercury in the flesh. However, there was no significant relationship (p >: 0.05) between mercury content in the fruiting bodies of this speciesto soil mercury concentrations. A significant (p < 0.01) positive relationship between mercury content in caps to underlying soil was noted for European cow bolete (Suillus bovinus), while a negative relationship between mercury content in caps and stalks to underlying soil was observed for Sandy knight-cap (Tricholomaflavovirens), Shaggy scale-head (Pholiota squaroso-adiposa),Gypsy mushroom (Rozites caperata) and Pine spike cap (Chroogomphus rutilus).

Water quality analyses were performed on littoral water samples, collected on Lake Ohrid in 2002 (January, February, June, July, August and September). Several microbiological parameters were compared. The number of Escherichia coli, the number of organotrophic bacteria and the phosphatase activity index were measured. Samples were collected along the shore of Lake Ohrid, i.e. at the village of Pestani, at Hotel Metropol, in Ohrid Bay and at the lake inflow of River Velgoska. The results of the study show that the different parameters are not compatible in terms of water quality characterization. The differences found are discussed below.

This report presents investigation performed as a part of a wider study desined to examine the level of pollution effects on fish in Ohrid lake (The Former Yugoslav Republic of Macedonia). Faunal investigation of the fish Barbus meridionalis petenyi Heck. were carried out at the five localities in Ohrid lake. Microscope analysis of histological preparation of barbel hepatic tissue displayed a dominant presence of granulomatous inflammation on a level of hepatocelular parenchyme and cholangiofibrosis on a level of hepatic bile duck. The analysis did not exhibit any correlation between the granulomatous inflammation and the manifestation of the cholangiofibrous alterations.

Sasko Lake, with surface area of 3.4 square km and depth of about 8 m, is situated is southwestern part of Montenegro (Serbia&Montenegro), within the hydrosystem of Skadarsko Lake. During 2002 and 2003, seasonal dynamics of main hydrographic, physical, chemical and biological parameters of this ecosystem was monitored. Reference measuring spots are defined, and in these places all future monitoring of system state will be accomplished. Also done are the preliminary batimetric measurements and maps of spaces suitable for development of breeding activities. In order to develop aquaculture as a strategic interest of Montenegro (Serbia&Montenegro), it is necessary to utilize these important potentials and place this important natural resource in full fuction. Included are the list of all fish species living in the lake, as well as the suggestion of species that could be suitable for commercial breeding.

In this paper are presented the length and weight growth of bleak Alburnus alburnus alborella Filippi from Lake Ohrid, R. Macedonia. The results of the length growth are presented by percent growth, absolute length growth in mm., the length growth rate (CI), the length growth constante (CIt), and growth characteristic (K). The weight growth are presented by percent growth and absolute weight growth in grams.

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.

This work show and compare results of chlorophyll 'a' and phaeophytin 'a' concentrations during three years systematic examination. The samples were collected from the fourth sector of Palic lake, ones a month, during 2000, 2001, and 2002 using method by Szilagyi. Comparing values, a great seasonic changes of chlorophyll 'a' and phaeophytin 'a' concentrations is noticed.

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.

The most extended and deepest belt of macrophytic vegetation, the belt which almost without exceptions define the lower limit of littoral region of Lake Ohrid, consists algae from the family Characeae. Permanent presence of sunlight, well oxygen saturation, their density which decreases the waves action, together with the facts that these algae are food and shelter for the numerous endemorelic species from the very rich fauna of macro invertebrates, make the stonworts the most attractive life habitat in Lake Ohrid. Our results are found on researching of three types facies from four different localities in Lake Ohrid: sandy-muddy facies without of stoneworts, facies covered by stoneworts and facies covered by Gastropod and Bivalvia shells, also without of stoneworts. Without exceptions, in all four localities we approved the mentioned affirmation about the great importance of the stoneworms as life habitats, both by the number of present taxa and the density of the macro invertebrate communities.