Infestation of blue mussels (Mytilus edulis L.) by trematode larvae in various areas of the Murmansk coast of the Barents Sea

A parasitological examination of Mytilus edulis bivalves in several areas of the Murmansk Coast has been carried out. It has been established that blue mussels on the Murmansk Coast are infected by metacercaria trematodes from the families Echinostomatidae and Gymnophallidae; the former being found almost everywhere, and the second infection is noted only for the Ainov Islands region. The values of quantitative parameters of infestation in different regions have been given, the probable causes of the observed differences (taking into account the schemes of life cycles of parasites) have been considered. It has been revealed that the highest infestation of mussels is typical for the areas of large nesting colonies of birds (the Ainov Islands, Rybachy Peninsula) and on wide littoral beaches in the Kola Bay where birds actively feed at low tide. It has been established that the main limiting factors determining the degree of infestation of mussels by larvae trematodes and geographical distribution of invasion foci are the presence in the ecosystems of potential intermediate and final hosts of these helminths and the presence of sustainable ecological links between them. Water salinity and hydrodynamic conditions do not play a decisive role since both mollusks and their parasites have a high tolerance to a wide range of values of these parameters. Parasitism of metacercariae of trematodes in mussels causes negative consequences for the physiology and behavior of mollusks and can cause certain damage at artificial growing of mussels. Recommendations on the areas and conditions for the location of blue mussel plantations on the Murmansk Coast have been given. Preliminary, a parasitological examination of the littoral and sublittoral benthos and ornithological observations in the areas of location of mariculture objects are necessary.