[NUMBER DISTRIBUTION AND POPULATION STRUCTURE OF PROTEOCEPHALUS LONGICOLLIS (ZEDER, 1800) (CESTODA: PROTEOCEPHALIDEA), A PARASITE OF SMELT AND COREGONIDS].

The spatial structure and seasonal aspects in the number distribution of the cestode Proteocephalus longicollis population, maintained by trophic connections of specialized plankton-feeders (the vendace Coregonus albula L. and the smelt Osmerus eperlanus L.) in the Lake Onego were studied.

[PARASITES OF THE COMMON ROACH (RUTILUS RUTILUS L.) UNDER THE IMPACT OF INDUSTRIAL POLLUTION OF A LAKE].

The consequences of man-induced transformation of Lake Kostomukshskoe (tailings dump) related to increased mineralization and entry of highly dispersed dredge material not typical for northern lakes were studied using roach parasites as the example. It was found that the roach parasite fauna has been losing rare and scant parasite species of different taxonomic groups, mainly helminthes with an indirect life cycle. Common and dominant species of myxosporidians, monogeneans, trematodes of genera Diplostomum and Tylodelphys have been preserved.

[Zooplankton of Reservoirs in the Upper Reaches of the Kenti River System (Northern Karelia) under Long-Term Industrial Pollution Conditions].

An assessment is given for the contemporary state of zooplankton community in the waters of the upper reaches of the Kenti River system under the conditions of long-term potash-sulfate industrial pollution. This article presents a number of structural indicators of the zooplankton community that show simplification in the structure of species diversity and its reduction, as well as the disappearance of a number of systematic groups. It is noted that the number of zooplankton taxa increases with distance from the source of pollution (Kostomukshskoe and Kento lakes), and the average quantitative indicators also increase in this case.

[Population biology of cestode genus Triaenophorus in natural and man-made water bodies].

A comparative study of the frequencies of occurrence and distribution of the abundances of pike parasites, tapeworms of the genus Triaenophorus, was carried out in natural lakes and water bodies contaminated by the Kostomuksha mining and concentration mill (Northern Karelia). We demonstrate that the wide presence of T. crassus and T.

[Specific features of the numbers and structure of the population of Proteocephalus longicollis (Zeder 1800) (Cestoda: Proteocephalidea)--a mass parasite of whitefish Coregonus lavaretus L. under conditions of technogenic pollution of the water body].

The numbers, age structure, and morphological variation of the cestode Proteocephalus longicollis from whitefish of a natural water body (Kamennoe Lake) and those of Kostomuksha Lake polluted with wastes of the mining industry (Northern Karelia) have been studied. In the polluted water body, a high infestation of whitefish and domination of larval stages in the structure of the parasite population have been established. It is shown that under conditions of pollution, only one of the variations ofscolex signs dominates in the structure of phenotypic diversity.