Effect of parasite infection with Posthodiplostomum cuticola (Nordmann, 1832) on fish growth rate in Zaringol Stream in Golestan Province

This study investigated the effect of parasite infection with Posthodiplostomum cuticola on fish growth rate in Zaringol Stream in Golestan Province. A total number of 447 fish specimens (173 Capoeta capoeta gracilis, 111 Alburnoides eichwaldii, 131 Paracobitis malapterura, 32 Neogobius fluviatilis) were captured by electrofishing during December 2009 to September 2010. Total number of parasite on fish body was counted by investigating internal organ and surface of skin and branch. Results showed that slope of regression curves and condition factor were significantly lower in infected C. c. gracilis. N. fluviatilis was the most abundant infected fish in Zarringol Stream,. It seems that it's feeding dependence on benthos makes this fish more susceptible to infection by parasite