Trematode fauna (Platyhelminthes: Digenea) of some sea ducks wintering on the southern Baltic coast (NW Poland) – a general comparison

The common scoter Melanitta nigra, velvet scoter M. fusca and long-tailed duck Clangula hyemalis (Aves: Anatidae) are among the more abundant sea ducks on the southern coast of the Baltic in winter, but their parasitic trematode fauna (Platyhelminthes, Digenea) in this region is little known. The aim of this study, conducted in 2007–2009, was a general comparison of the trematode fauna of these ducks in NW Poland. The prevalence and intensity of trematode infection were 68.3% and 119.9 in common scoter (101 examined), 77.6% and 13.1 in velvet scoter (58 examined) and 70.6% and 23.7 in long-tailed duck (68 examined). The following trematodes were found: Diplostomum pungitii, Apatemon gracilis, Australapatemon minor, Typhlocoelum sisowi, Echinochasmus spinulosus, Echinoparyphium recurvatum, Psilostomum brevicolle, Psilotrema simillimum, Catatropis verrucosa, Notocotylus attenuatus, N. gibbus, Paramonostomum alveatum, Prosthogonimus ovatus, Levinseniella propinqua, Gymnophallus bursicola and Cryptocotyle concava. The common scoter differs from the velvet scoter and long-tailed duck in its statistically significantly higher prevalence of G. bursicola; from long-tailed duck in its higher prevalence and greater intensity of infection with P. alveatum; and from velvet scoter in its greater intensity of infection with C. concava. The velvet scoter is distinguished from the long-tailed duck by its greater intensity of infection with P. brevicolle, lower prevalence of L. propinqua and lower intensity of infection with C. concava. Links between the differences found and the biology and ecology of the hosts, as well as the means of transmission of the parasites, are also discussed.