Abstract
The aim is to study the morphological and ecological features of some nematode species of the genus Rhabdochona parasites of marinka fish in the Fergana Valley, Uzbekistan. Rhabdochona gnedini, Rhabdochona denudata and Rhabdochona hellichi turkestanica were detected as 5.3%, 7.9% and 3.7%, respectively. According to the Authors' knowledge, Rh. hellichi turkestanica was recorded in Uzbekistan and Central Asian republics for the first time. Rhabdochona spp. were only detected in the intestine of marinkas lived in the mountain rivers Rezaksay, Chodaksay and small tributaries of the Syrdarya river in western Fergana. The prevalence of Rhabdochona spp. in the marinka can be associated with a wide range of nutrition in the mountain rivers and small tributaries of the Syrdarya river, where it could eat large numbers of mayfly and caddis larvae that act as intermediate hosts of rhabdochona.