Andrey V . Tyutin

SUMMARY 
THE PREVALENCE OF CESTODESOF THE FAMILY LIGULIDAE IN CARP FISHFROM THE UPPER VOLGA RESERVOIRS AFTER INVASION OF BLACK-CASPIAN SEA TYULKA
A.V. Tyutin, V.I. Kiyashko
Institute for Biology of Inland Waters, Russian Academy of Sciences, 152742, Borok,  Nekouz District, Yaroslavl Region, Russia; e-mail: tyutin@ibiw.yaroslavl.ru
Long time dynamics for the level infection of bream
Abramis brama, roach  Rutilus rutilus, white bream
Blicca bjoerkna
and bleak
Alburnus alburnus
by  plerocercoids of
Ligula intestinalis
and
Digramma interrupta
in three Upper Volga reservoirs – Ivan’kovo, Uglich and Rybinsk – was studied. The highest level of infection was registered in populations of bream, the lover level – in populations of roach. In 1995-2000 a relative stability of the prevalence of plerocercoids was registered. On the contrary after increase a number of new invasive species black-caspian sea tyulka
Clupeonnella cultriventris
in 2001-2004 oscillations of the  prevalence of ligulides were shown.

It has been established that the newcomer Gmelinoides fasciatus has not have any considerable influence on the structure of the helminth community in perch fry of the Rybinsk Reservoir, since it began to be consumed by this year's brood as a valuable food component in autumn, already after the formation of the parasite worm community. http://elibrary.ru/item.asp?id=17641805

In 1992-2000 a total of 1441 specimens of bream Abramis brama from
four reservoirs of the Volga River basin were captured and examined. A
positive correlation between the level of fish parasites infection by Ligula
inteslinalis (L.) and Digramma interrupta (Rud.) and place in the cascade
of freshwater bodies has been revealed. A relative stability of the prevalence of helminths at the low level in three Upper Volga reservoirs was  registered. On the contrary, a maximal number of plerocercoids was found in the Gorky Reservoir (Middle Volga basin). The prevalence of cestodes is great in low section of the reservoir in comparison with others water bodies. In the last years the quota of D. interrupta plerocercoids in total  number of cestodes has greatly increased to 30-40% in Rybinsk and Gorky  reservoirs.

An attempt was made to find the relationship between the basic demographic parameters and types of the spatial structure in three groups of the imaginal hemipopulation of a common intestinal helminth of percid fishes-trematode Bunodera luciopercae (Muller). In the Rybinsk reservoir the most dispersed frequency distribution of empirical values of an actual fecundity was found in samples of marites from adult perch (Perca fluviatilis L.). Before a mass spring elimination of trematodes the similar type of the eggs number distribution was registered for parasites from a perch fry. The least asymmetry of graphic distribution of fecundity frequencies was observed for the largest helminths from ruffe (Gymnocephalus cernuus L.). The scatter in fecundity values depends mainly on hostal variability of a body length of trematodes and duration of the summer-autumn period of infection of some local hemipopulations by metacercaries.

Objective: To evaluate the level of in­ fe ction of ruff (Gymnocephalus cernua) by the cestode Proteocephalus cernuae (Gmelin, 1790) and to study its seasonal maturation in the Rybinsk Reservoir, one of the largest reservoirs in the world. Materials and Methods: In 1992-1994 a total of 716 specimens of fish, mainly from the Volga part of the reservoir, were captured and examined. Results: Seasonal variation in preva­ lence of the tapeworm was observed (win­ ter: 51.2±2.9, spring: 60.5±3 .9, summer: 48.6±3 .7, autumn: 37.7±5.5%). Unlike P.

Среди 22 видов кладоцер из планктонных проб, взятых в природных условиях, зараженными буно-дерой оказались только 5 видов, обитающих в зарослях прибрежной растительности. В эксперименте церкариями Bunodera luciopercae удалось заразить все использованные 13 видов Cladocera и 3 вида Ostracoda. Представители Copepoda, Amphipoda, Isopoda не были инвазированы ни в естественных, ни в экспериментальных условиях. Выявлена положительная зависимость между уровнем зараженности и размерами рачков. Показано отрицательное влияние метацеркарий Bunodera luciopercae на выжива-емость рачков в эксперименте. Ключевые слова: трематода, Bunodera luciopercae, вторые промежуточные хозяева, ракообразные, метацеркария. All specium of Cladocera (13 species) and Ostracoda (3 species) used in the experiment were infected by cercariae of trematode Bunodera luciopercae. Among 22 investigated species of Cladocera only 5 species inhabiting the littoral vegetation were invaded in natural conditions. Species of Copepoda, Amphipoda and Isopoda were not infected neither in nature, nor in the experiment. The dependence of the level of infection of their size has been revealed. The negative influence of metacercariae Bunodera luciopercae on the survival of crustaceans was studied.

A positive correlation between the size of tributaries and prevalence of plerocercoids of Triaenophorus nodulosus was discovered. Negative correlations was observed for tapeworms Proteocephalus spp. In addition it was shown that in different years the spring level of floodwaters was the main factor determining the extent of fish infection.

An ultrastructure of microsporidia spores of Glugea anomala from Pungitius pungitius, G. gasterostei from Gasterosteus aculeatus, G. fennica from Lota lota, G. hertwigi from Osmerus eperlanus, G. acerinae from Gimnocephalus cernua and Glugea sp. from Perca fluviatilis is described. Similar spore organisation in these microsporidian species has been established. A conclusions about close phylogenetic relationships of species examined and homogeneity of the genus Glugea are proposed. Problems of species validity of G. anomala, G. gasterostei and G. weissenbergi from sticklebacks and microsporidian species from a common ruff and perch are discussed.

The seasonal dynamic of infection of perch underyearlings by trematode Bunodera luciopercae has been found in the five small rivers of the Volga part in the Rybinsk reservoir. Insignificant mortality of trematodes in autumn-winter period was registered.

The studies were made of European vendace and Caspian kilka in the Rybinsk reservoir. About 50\% parasites were common for both fish species. The population of vendace is very sparse: 9 species of parasites were found and only the cestode Triaenophorus crassus plerocercoid was a specific parasite for Salmoniformis fish host. The number of the population of Caspian kilka increases rapidly. The list of parasites for the Caspian kilka includes only 6 common species. Probably the loss or an absence of specific parasites and resistance to native helminths give a good advantage for fish invaders in comparison with aboriginal species.

The seasonal dynamics of the maturation of trematode Bunodera luciopercae was investigated in 1992-1998. The actual fecundity of adult helminths from the ruff, perch, sander and volga pike-perch in the Rybinsk Reservoir was registered in the end of spring. The accumulation process of eggs reflected the host alteration and depended on the food ration, body length and sex of hosts.

The mass infection of larvae and youngsters of carp fishes with the peritrichoid Ambiphrya ameiuri has been recorded in natural condition in the Rybinsk water reservoir (Russian Federation). The uneven localisation of ambiphryans on the body surface has been observed on the hosts Blicca bjorkna and Abramis brama. Most high density of parasites was on the breast, back and tail fins. The morphological variability of ambiphryans in dependence upon their localisation on the fish body has been observed

An attempt was made to find the relationship between the basic demographic parameters and types of the spatial structure in three groups of the imaginal hemipopulation of a common intestinal helminth of percid fishes -trematode Bunodera luciopercae (Muller). In the Rybinsk reservoir the most dispersed frequency distribution of empirical values of an actual fecundity was found in samples of marites from adult perch (Perca fluviatilis L.). Before a mass spring elimination of trematodes the similar type of the eggs number distribution was registered for parasites from a perch fry. The least asymmetry of graphic distribution of fecundity frequencies was observed for the largest helminths from ruffe (Gymnocephalus cernuus L.). The scatter in fecundity values depends mainly on hostal variability of a body length of trematodes and duration of the summer-autumn period of infection of some local hemipopulations by metacercaries.