Metacercariae of the trematode family Bucephalidae from cyprinid fish of the Gulf of Finland.
Three species of trematode metacercariae of the family Bucephalidae have been found in the cyprinid fishes of the Gulf of Finland. Rhipidocotyle campanula is widespread and localizes only in gills. A metacercariae of R. fennica are first observed for the fauna of Russia, are also numerous, and are located in rays of fins and their muscles. For the Gulf of Finland, Bucephalus polymorphus is an invasive species together with its host bivalves Dreissena polymorpha. All early reports of B. polymorphus being found in the fish of the Gulf of Finland are unreliable.