Dynamics of the Baltic clam Macoma balthica (Mollusca: Bivalvia) infection with digeneans from the Gymnophallidae family in the Gulf of Gdańsk

Macoma balthica is a marine bivalve commonly occurring in the boreal zone. It is one of the most common zoobenthos species in the Baltic Sea, including the Gulf of Gdańsk, and a significant element of the food web. Observations of the infection prevalence in M. balthica from different parts of Gulf of Gdańsk were conducted in 2007-2008, taking into account the water depth. Metacercariae of Gymnophalloides (=Lacunovermis) macomae (prevalence: 89.0%) were found, as well as sporocysts with metacercariae of Parvatrema affinis (prevalence: 1.1%) and unidentified sporocysts with cercariae (prevalence: 1.3%). The most infected clams were found on the shallowest research station (30 m).