Parasite fauna of the tench, Tinca tinca (L.) from selected lakes of the north-western regions of Poland

In the tench collected from three lakes of the north-western region of Poland, namely: lake Ińsko, lake Mielno, and lake Woświn, a total of 20 parasite species was recorded. Representatives of the following species were commonly found: Ichthyophthirius multifiliis, Dactylogyrus triappendixis, Asymphylodora tincae and Ergasilus sieboldi (the prevalence ranged from 34.37 to 65.62%). Trypanosoma sp., Myxobolus ellipsoides, Trichodina sp., Trichodinella epizootica, metacercariae of Tylodelphys clavata and Skrjabillanus tincae were recorded relatively often (18.75-28.12%). The presence of Thelohanellus pyriformis, Caryophyllaeus laticeps, egss of Sanguinicola sp., metacercariae of Diplostomum sp., and larvae of Raphidascaris acus (9.37% of infection) were recorded less frequently. The remaining parasites, namely: Philomerta ovata, Piscicola geometra, Acanthocephalus anguillae, A. lucii, and Argulus foliaceus occurred as single specimens (3.12% of infection). Protozoans T. epizootica and nematodes P. ovata were recorded for the first time in the tench in Poland, whereas 18 species of parasites have not been noted yet in the north-western region of the country.