Parasitic nematodes of pumpkinseed sunfish (Lepomis gibbosus L., 1758) from warm-water canal of a power plant in Szczecin, Poland.

Parasitological examination of 273 pumpkinseed sunfish, caught in the warm water channel at the Dolna Odra Power Plant in Stare Czarnowo near Szczecin was carried out. The total lengths of the fish ranged from 6.8 to 18.1 cm (13.3 cm means), infected fish 9.8 to 17.5 cm. In 48 individuals the presence of nematodes representing 4 species has been found: Schulmanela petruschewskii, Raphidascaris acus, Spiroxys contortus and Contracaecum sp. In total the number of nematodes found was 319, the mean intensity of infection was 6.64. The greatest number of fish infected with parasites was caught in June and April. The most frequently noted has been S. petruschewskii, found in adult forms as well as in larval stage in the liver, intestine, stomach and peritoneum in 40 specimens. In total the number of this nematode found was 305. The least frequent has been S. contortus, rarely found in Poland and for the first time noted in sunfish. Usually one fish was invaded by one species of nematodes.