FIRST DATA ON PARASITES OF NEOGOBIUS ILJINI (PERCIFORMES, GOBIIDAE) OF THE MIDDLE VOLGA

The results of a study of the fauna of multicellular parasites of the Caspian bighead goby Neogobius iljini (Vasiljeva et Vasiljev, 1996) in three reaches of the Kuibyshev reservoir (Middle Volga) are presented. Twelve species and undefined forms of parasites were found, including a specific to the fam. Gobiidae metacercaria Holostephanus cobitidis . The most diverse fauna of macroparasites is observed in the lower reaches of the reservoir (Priplotinny reach). The dominant species in the parasite fauna of the Caspian goby of the studied reservoir is the alien fluke Nicolla skrjabini , whose natural range is limited to the rivers of the Azov and Black seas basin.

Gastrointestinal helminth fauna and helminth communities of bleak (Alburnus alburnus, L. 1758) from lower section of Danube River

The present study presents the results from examinations of bleak’s endohelminth species and structure of helminth communities from the Bulgarian part of the Lower Danube River. In 2015 and 2016, on a seasonal manner, 91 specimens of Alburnus alburnus (Linnaeus, 1758) (bleak) were examined with standard techniques for parasites. Five species of parasites: Nicolla skrjabini (Ivanitzky, 1928), Ligula intestinalis (Linnaeus, 1758), Acanthocephalus lucii (Müller, 1776), Pomphorhynchus laevis (Müller, 1776) and Contracoecum microcephalum (Stossich, 1890), larvae were identified. The analysis of the dominant structure of the found parasite species is presented to the component and infracommunities levels. All parasite species were accidental for the parasitic communities of examined fish with the exception of P. laevis and N. skrjabini. P. laevis was a core parasite species and N. skrjabini was a component parasite species for the helminth communities of bleak. The parasite communities of A. alburnus were discussed and compared with previous research data on parasite communities of bleak from River Danube in Bulgaria. New data for helminths and helminth communities of A. alburnus from Danube River (biotope Vetren) and their seasonal occurrence are presented.

Materials on multicellular parasites fauna of the ruffe Gymnocephalus cernuus Linnaeus, 1758 (Pisces: Percidae) from the Saratov water basin

Objective of research. Data on the species composition of the fauna of multicellular parasites and the infection rates of the pope ruffe Gymnocephalus cernuus Linnaeus, 1758 from Mordovian floodplain of the Saratov reservoir (the middle part) are pesented. Materials and methods. 53 ruffe individuals were investigated in spring and summer 2012 – 2015 by incomplete parasitological post-mortem examination (Bykhovskaya-Pavlovskaya, 1985). 19 species of multicellular parasites belonging to 7 classes: Monogenea - 1, Cestoda - 1, Trematoda - 11, Nematoda - 3, Acanthocephala - 1, Bivalvia - 1, Crustacea – 1 were registered. The largest group are flukes; more than half of species (8) are larval forms, which is the result of bottom living of the host. The significant diversity of larval stages of helminths (8 species of trematodes and 2 species of nematodes) shows the involvement of the ruffe as an intercalary, supplementary and/or reservoir host in the circulation of parasites in fish, birds and mammals. 7 species of parasites infest the ruffe on the food chain; 12 species – using the active infestation way. Results and discussion. The studied parasite fauna contains one species narrowly specific for the ruffe (monogenea D. amphibothrium (Wagener, 1857) and 2 species typical for percoid fishes (cestoda Proteocephalus percae (Müller, 1780) and trematoda Bunodera luciopercae (Müller, 1776). 2 alien species Nicolla skrjabini (Iwanitzky, 1928) (marita) and Apophallus muehlingi (Jägerskiöld, 1898) (mtc.) whose natural habitat is limited by the rivers of the Azov-Black Sea and Baltic Sea were registered in the fauna of multicellular parasites of the ruffe from the Saratov reservoir. The most common ruffe parasites are Diplostomum and Ichthyocotylurus metacercariae metacercaria infesting fish by penetrating through the body covers. These metacercariae as well as Apophallus muehlingi metacercariae are pathogenic to fish.

Communities of metazoan parasites of two fishes of the Proterorhinus genus (Actinopterygii: Gobiidae)

Metazoan parasite communities of two gobiids, Proterorhinus marmoratus and P. semilunaris, which are common small-sized fishes native for the Black Sea basin, were studied. The parasite component community of P. marmoratus is represented by 11 species (one monogenean, one cestode, five digeneans, two nematodes, and two acanthocephalans). P. semilunaris had 5 species (one monogenean, one cestode, one digenean, one nematode, and one acanthocephalan). Acanthocephaloides propinquus has a great tendency to join the infracommunity. The differences between the parasite component communities of two Proterorhinus gobies are explained by different quality of habitats and available intermediate hosts. The component community of parasites of P. marmoratus is formed by brackish-water and marine parasite species, and that of P. semilunaris consists of limnetic parasite species. The euryhaline G. proterorhini is the only parasite species found in both P. marmoratus and P. semilunaris. In both species of gobiids, the main abundant parasite species (A. propinquus in P. marmoratus and Nicolla skrjabini in P. semilunaris) infest the host by feeding on crustaceans.