ВИДОВОЕ РАЗНООБРАЗИЕ ГЕЛЬМИНТОВ ПИЩЕВАРИТЕЛЬНОЙ СИСТЕМЫ ЛЕЩА И ПЛОТВЫ САРАТОВСКОГО ВОДОХРАНИЛИЩА

Abstract

The data on helminths of the digestive system of the bream Abramis brama Linnaeus, 1758 and the common roach Rutilus rutilus Linnaeus, 1758 (Osteichthyes, Cyprinidae) from the middle part of the Saratov reservoir (Koltsovo-Mordovinskaya fl oodplain) are given. In 2013–2016, 40 specimens of A. brama and 47 specimens of R. rutilus were studied by standard parasitological methods. Bream has 8 species of worms of different systematic groups, including Cestoda – 2, Trematoda – 1, Chromadorea – 3, Acanthocephala – 2. The community of intestinal and liver parasites of roach includes 5 species: Cestoda – 1, Aspidogastrea – 1, Chromadorea – 2, Acanthocephala – 1. The degree of invasion of fi sh by helminths circulating through food webs is low. The bream is dominated by the carp-specifi c nematode Rhabdochona denudata (Dujardin, 1845) Railliet, 1916 (Spirurida, Rhabdochonidae) (invasion intensity 27.5 %, invasion intensity 1–126 ind., abundance index 5.8 ind.). No dominant parasites were found in the common roach, three species (Contracaecum microcephalum (Rudolphi, 1819), Aspidogaster limacoides Diesing, 1835 and Raphidascaris acus (Bloch, 1779)) have the status of subdominants. During the research period, there were signifi cant fl uctuations in the qualitative and quantitative indicators of fi sh invasion (species composition of parasites, their occurrence and average number), which is determined by the feeding characteristics of bream and roach in each specifi c year.