Seasonality of Ichthyophthirius multifiliis in the Trout (Oncorhynchus mykiss) Farms of the Eastern Black Sea Region of Turkey

Rainbow trout (Oncorhynchus mykiss) ranging from fry to marketing size were sampled monthly in 2002 from three farms to determine prevalence, abundance, and intensity of Ichthyophthirius multifiliis, the causative agent of ichthyophthiriasis. I. multifiliis was present and active in the farms from June to August. However, outbreaks of ichthyophthiriasis occurred only late in summer. Persistent presence of the ciliated parasitic protozoan in the farms suggests that I. multifiliis is endemic in the region. Thus, effective measures such as decreasing of host densities and routine prophylactic treatments should be applied to decrease or eliminate the impact of the parasite on growth of the host. This is the first extensive study providing seasonal data on the presence of I. multifiliis in the Eastern Black Sea Region of Turkey.