EN
A female saithe, Pollachius virens (L.), caught in the Baltic Sea, off Polish coast, was infected with microsporidian Glugea sp., nematodes Anisakis simplex (L3), Contracaecum osculatum (L3), Hysterothylacium aduncum aduncum, H. aduncum gadi, and acanthocephalan Echinorhynchus gadi; each of which constitutes a new geographic locality record for these species in the Baltic Sea. H. aduncum aduncum and H. aduncum gadi are described, illustrated, and their detailed measurements are provided.