Helminth communities of Coregonus lavaretus (Salmonidae: Coregoninae) from Lake Kamennoye (Kostomuksha State Nature Reserve, Russia)

Abstract

Macroecological models are useful for assessing trends in variability for developing monitoring strategies of successional changes and anthropogenic transformation of aquatic ecosystems. Modelling of the relationships of the generalised population indices also makes possible to reveal qualitative differences in the structure of parasite component communities. We analysed helminth communities of Coregonus lavaretus from a natural water body, Lake Kamennoye (Kostomuksha State Nature Reserve, Russia). The component community of metazoan parasites of C. lavaretus was represented by nine helminth species. Infection with cestodes (two species), nematodes (three species), and trematodes (one species) reflects the presence of zooplankton, aquatic insects and molluscs in the diet of fish, while infection with trematode larvae (three species) occurs by percutaneous penetration. The complete ITS1-5.8S-ITS2 cluster of the rRNA gene was sequenced in order to identify trematode larvae. Metacercariae of Diplostomum sp. LIN 5 were the most abundant among them. Using populational approaches, we described the species richness and the diversity of infra- and component communities of the parasites. We also described the species composition and the structure of the component community, the distribution and the accumulation rate of species richness, and the relationships between the infection intensity and the prevalence. Five species (Diplostomum sp. LIN5, Tylodelphys immer, Crepidostomum farionis, Proteocephalus longicollis, and Raphidascaris acus) were considered as the core species of the component community, while other helminths were considered as satellite species. We conclude that infra-communities play a key role in the formation of species richness, structure and abundance of the parasitic component community of C. lavaretus. Infra-communities in younger age groups of C. lavaretus are characterised by the paucity and a relatively high diversity of the species composition of parasites, which is probably a consequence of their diverse diet. In older fish, the species richness of infra-communities increases but the species diversity of the parasites declines, indicating a pronounced dietary specialisation. An analysis of species richness and population characteristics indicates that in Lake Kamennoye, the parasite communities of C. lavaretus are fairly stable, which reflects the stability of the entire lake ecosystem.