Comparative Analysis of Parasite Load on Recently Established Invasive Pumpkinseed Lepomis gibbosus (Actinopterygii: Centrarchidae) in Europe

Abstract Purpose The aim of this study was the comparative analysis of the parasite communities of new populations of invasive pumpkinseed ( Lepomis gibbosus ) in western Ukraine with pumpkinseed from Czechia, where populations have rapidly expanded over the last two decades. Methods Sampling took place at three localities in the western part of Ukraine (i.e. Dobrotvir Reservoir (Vistula basin), Burshtyn Reservoir (Dniester basin), Mynai Pond (Danube basin)) and four in Czechia (i.e. Oxbow D2, Heršpický Pond (Danube basin), and Kolín oxbow and Římov Reservoir (Elbe basin). Results In total, 11 parasite taxa were recorded in Ukraine and 17 in Czechia. Four species were co-introduced from North America with their host, i.e. the myxosporean Myxobolus dechtiari , the monogeneans Onchocleidus dispar and Onchocleidus similis , and metacercariae of a trematode Posthodiplostomum centrarchi . High dominance indices were related to a high abundance of co-introduced parasites, i.e. O. similis in Mynai pond and P. centrarchi in Dobrotvir Reservoir. Overall abundance of acquired parasites was generally low. Conclusion This study shows that parasite communities in recently established pumpkinseed populations in the western part of Ukraine and Czechia are less diverse than those established in Europe for decades. The generally low parasite load in these new populations may play an important role in their ability to successfully establish and create strong populations by providing a competitive advantage over local species.