Gyrodactylus (Monogenea, Gyrodactylidae) Parasite Fauna of Fishes in Some Rivers of the Southern Caspian Sea Basin in Mazandaran Provin Ce

Background: members of the genus gyrodactylus species are one of the extensive groups of monogenean ectoparasites which parasitize marine, brackish and freshwater fishes. objectives: the main objective of the present study is the identification and diagnosis of the gyrodactylus species on the fishes in some rivers of the southern caspian sea basin in mazandaran province. methods: the field investigations were carried out from march 2015 to june 2016 and approximately, 1240 fish specimens belonging to two families, nine genera and nine species from babolrud, tajan, shirud, tonekabon, nekarud, siahrud, talar and haraz rivers were examined. results: at least eleven gyrodactylus species were isolated from skin and gills of the examined fishes. among them, gyrodactylus mutabilitas, g. sprostonae and g. prostae have been previously reported to be found in iran. the rest, including gyrodactylus ctenopharyngodonis, g. gobioninum, g. katharineri, g. nemachili, g. proterorhini, g. ophiocephali, g. varicorhini and g. vimbi are reported for the first time from iranian fishes in the present study. conclusions: the host spectrum of gyrodactylus species in iran is actually wider, and further research may demonstrate that classification of individual species in terms of their host specificity will have to be changed and additional species of gyrodactylus species would be found.