[An example of anthropogeneous succession in the ecosystem of the Verkhnetulomsky Water Reservoir (the Tuloma River Basin, the Kola region)].

The destruction of initial biocenoses in the ecosystem of the Verkhnetulomsky Water Reservoir caused deep succession processes. As a result of the loss of the amphipod group in the benthos, replacement of the trophic links in fishes took place in the biocenosis of the reservoir. Benthos feeders changed over to the feeding on zooplankton and, as a result, became the constituent of the predators'diet. The structure of parasitic systems has changed. The parasites using amphipods as intermediate hosts have been and, on the contrary, the abundance of parasites infesting fishes through feeding of the latter on zooplankton has increased. Among the parasites, Triaenophorus crassus Forel became the cause of the appearance of stable triaenophorosis focus.

[Peculiarities of the distribution of freshwater Myxosporea in the European part of palaearctic].

The complete taxonomic composition (158 species of freshwater Myxosporea inhabiting European Part of Palaearctic is presented. Their distribution by faunistic complexes and groups is established. Analysis of similarity between myxosporean faunas by zoogeographical areas and districts is carried out. Historical background of the distribution and formation of the freshwater myxosporean fauna is discussed.

[Ecological-faunistical review of fish parasites in the Umbozero Lake (the Kola Peninsula)].

Data on fish infestation by parasites in the Umbozero Lake are given. 90 species of parasites were identified including 16 species of Myxosporea, 2 Suctoria, 18 Peritricha, 12 Monogenea, 13 Cestoda, 18 Trematoda, 5 Nematoda, 2 Acanthocephala, 2 Hirudinea, and 2 species of Crustacea. Character of parasites' distribution in fishes of this lake and ecological peculiarities in the host-parasite system are demonstrated.

[Parasite fauna of the burbot Lota lota L. in body of water of the Kol'skii peninsula].

The results of a parasitological study of the burbot Lota Iota L. inhabiting the Kola region are presented. 51 species of parasite were found on burbot in 16 waterbodies belonging to the White Sea and Barents Sea basins (Muxosporea - 7, Suctoria - 1, Peritricha - 6, Monogenea - 1, Cestoda - 6, Trematoda - 13, Nematoda - 6, Acanthocephala - 5, Hirudinea - 3, Bivalvia - 1 and Crustacea - 2 species). Data on the infestation of burbot by different parasite species and their prevalence in investigated waterbodies were obtained.

[Parasite fauna of the perch fishes Percidae in waterbodies of the Kola Region].

Results of the parasitological investigation of two species of perch fisches (perch Perca fluviatilis and ruff Gymnocephalus cernuus) from Kola Region are given. 63 species of parasites were found on perch in 16 waterbodies belonging to the White Sea and Barents Sea basins (Myxosporea--3, Pleurostomata--1, Suctoria--2, Peritricha--21, Protozoa incertae sedis--1, Monogenea--2, Cestoda--6, Trematoda--10, Nemadota--8, Acanthocephala--4, Hirudinea--1, Bivalvia--1, Crustacea--3). 33 species of parasites were found on ruff in 5 waterbodies belonging to the White Sea basin (Cyrtostomata--1, Hymenostomata--1, Peritricha--8, Monogenea--2, Cestoda--6, Trematoda--9, Nematoda--2, Acanthospehala--2, Bivalvia--1, Crustacea--1). Data on the infestation of perch and ruff by different parasite species are obtained, occurrence of the parasites in the examined waterbodies is shown.

[Parasite fauna in sticklebacks (Gasterosteidae) from bodies of water of the Kola region].

The results of a parasitological study of the two species of sticklebacks (Pungitius pungitius and Gasterosteus aculeatus) inhabiting the Kola region are presented. The 42 and 14 species of parasite were found in the nine-spined and three-spined stickleback, respectively. The paucity of the parasite fauna in the three-spined stickleback is observed. Distribution of parasites in Kola waterbodies and ecological peculiarities in system "parasite-host" are presented.

[The causes of the formation of an intensive focus of triaenophoriasis in the upper Tuloma River reservoir]. / O prichinakh formirovaniia intensivnogo ochaga trienoforoza v Verkhnetulomskom vodokhranilishche.

Observations on the Triaenophorus crassus invasion in Coregonus lavaretus and Esox lucius were carried out in the period of 1984 to 1989 in the upper Tuloma River [correction of Verkhnetulomsk] water reservoir and Pechozero water body (the Pecha River) which form a common basin. Significant differences were noted in the infection rate of fishes with this parasite in the above water bodies. In Pechozero, where there are preserved natural conditions and therefore an ecological equilibrium in the host-parasite system, T. crassus is not abundant and the infection rate of C. lavaretus and E. lucius with this parasite is low. In the upper Tuloma River [correction of Verkhnetulomsk] water reservoir, due to the dropping out of the amphipod group of benthos from the biocoenosis of the water body, there has been formed a close ecological connection between copepods, C. lavaretus and E. lucius that resulted in the increase of T. crassus and gave rise to Triaenophorus infection of C. lavaretus here.

[Effect of hydraulic structures and water storage basins on the parasitic fauna of the Atlantic salmon (Salmo salar)]. / Vliianie gidrosooruzhenii i vodokhranilishch na parazitofaunu atlanticheskoi lososia (Salmo salar).

157 specimens of Salmo salar L. belonging to different age groups were examined in the region of the Lower-Tuloma hydropower-station. 13 species of parasites (of them 5 are freshwater) were found in anadromous migrants. The character of the parasite fauna and the structure of fishes' scale have shown that some salmons cannot get the fishrunning over and stay in summer months under the damb where become infected with freshwater parasites. 19 species of parasites (of them 14 are freshwater) were found in catadromous migrants. These fishes cannot penetrate through the damb of hydroconstruction beyond the limits of the reservoir and pass here to an active feeding that is indicated by a rich composition of freshwater parasite fauna. The infection of adult salmons with plerocercoids of Triaenophorus crassus during the spawning migration points to the presence of trienophorosis nidus in this water reservoir. Parasite fauna of salmon smolt, represented by 7 species, is not affected by the water reservoir and hydroconstruction. The smolt does not stay too long in the reservoir and early stages of its seaward migration do not coincide with the termination of the development of the invasional stages of procercoids of Pseudophylidae.

[2 new species of parasites of fish, Myxobilatus schulmani sp. n. and Apiosoma longiciliaris sp. n. of the water reservoirs of the Kol'sk peninsula]. / Dva novykh vida parazitov ryb Myxobilatus schulmani sp. n. i Apiosoma longiciliaris sp. n. vodoemov Kol'skogo poluostrova

Two new species of parasitic Protozoa are described, one of Myxosporidia and the other of Peritricha Sessilia. Myxobilatus schulmani sp. n. from Pungitius pungitius is near to M. paragasterostei but differs from it by the rhombus form of the spore, by less dimension of polar capsules. The spore of M. shulmani is longer and less broader than that of M. paragasterostei. Apiosoma longiciliaris sp. n. was found on the gills on Esox lucius and Phoxinus phoxinus. It is near to A. dallii but its micronucleus is situated over the macronucleus and has a stick like form.

[Monogenea and fishes of some fresh water reservoirs of the Kol'sk peninsula]. / Monogenei s ryb nekotorykh presnovodnykh vodoemov Kol'skogo poluostrova

25 species of Monogenea were found in the basins of the Ponoi, Pjalitsa and Varzuga rivers. The belonging to faunistic complexes is indicated for 29 species of monogeneans known at present for water bodies of the Kola peninsula. On the basis of the distribution of Monogenea in the Ponoi and due to its hydrological regime and geological past the introduction of freshwater fauna into this water body via the Varzuga river is suggeste.

[Monogenea of fishes from various fresh water ponds of the Kola peninsula].

25 species of Monogenea were found in the basins of the Ponoi, Pjalitsa and Varzuga rivers. The belonging to faunistic complexes is indicated for 29 species of monogeneanus known at present for water bodies of the Kola peninsula. On the basis of the distribution of Monogenea in the Ponoi and due to its hydrological regime and geological past the introduction of freshwater fauna into this water body via the Varzuga river is suggested.