Trichodinid infections in internal organs of shorthorn sculpin (Myoxocephalus scorpius) collected around an industrial harbour in Nuuk, Greenland

Trichodinids are parasites generally found on gills and skin of a broad number of aquatic animals. Only a small number of endozoic species has been reported from the urinary tract, intestine and urogenital system in some fish, amphibians and molluscs. This is the first report on the presence of endozoic trichodinids in the spleen, kidney and liver of shorthorn sculpin (Myoxocephalus scorpius). In the present study, trichodinids displayed some of the typical morphological characteristics of endozoic trichodinids with narrow blades and straight rays of adhesive disc denticles. The parasites were observed at a relatively high prevalence (23.9%). There was a positive correlation between intensity of endozoic trichodinids in the internal organs and ectozoic trichodinids on the gills (R = 0.5, n = 46, P < 0.001) whereas there was no correlation between intensity of endozoic trichodinids and the host's body length, body weight or liver weight. Infection levels of endozoic trichodinids were not dependent upon sculpin sex and there was no effect of sampling locations on prevalence and intensity of endozoic trichodinids.