Occurrence of Chilodonella hexasticha (Ciliophora, Protista) on farmed rainbow trout (Oncorrtynchus mykiss) throughout the season

Abstract

An examination of rainbow trout Oncorhynchus mykiss for ectoparasites, on three not so distant fish farms with independent water supply in Eastern Serbia from March to November 1998, resulted in finding three ciliate (Chilodonella hexasticha, Ichthyophthirius multifiliis, Apiosoma piscicola var. minor), one trematode (Gyrodactylus sp.) and one mould (Saprolegnia sp.) species, making a total of five parasite species. The Chilodonella hexasticha was recorded only on one of the farms, being in the highest extensity in May. This appeared to be the most prominent occurrence in the independent pattern of infestation dynamics of other parasites (Apiosoma, Gyrodactylus, Saprolegnia) recorded on that fish farm, as derived by Correspondence Analysis. The Friedman ANOVA test revealed a significant difference in extensity of occurrence of different parasites through the season, due to the significantly greater infestation with Gyrodactilus and significantly lower extensity of infestation with Saprolegnia.