Survey on Dactylogyrosis in Caspian Frisian Roach (Rutilus frisii kutum)Caused by Dactylogyrus frisii

During late March to August (2009) a total of 100 specimens of kutum fish fries were collected from pond fishes in Shahid Ansari Fish Culture Center (Rasht, Guilan). The fries in aquaria were treated by Organophosphate (Mazoten) as long duration bath at a concentration of 0/25-0/5ppm. Such treatments were repeated during different seasonal periods. For infection to take place in kutum fish fries, the collected Dactylogyrus frisii by pipette were exposed to the gill of the fries with 10-20 Parasites each species. After ensuring that infection has success fully been taken place (After 2 weeks) the gills of experimentally infected fries were survey and the gill filaments were fixed in 10% formalin solution. Histological studies were performed only on changes on the gill of kutum fish fries caused by Dactylogyrus frisii. The results obtained in this study indicated that the D. Frisii caused various abnormalities in copious mucus including congestion, hemorrhages, necrosis and destruction of secondaiy gill lamella, hyperplasia and fusion in gill lamella. Consequently, damages specific toD. Frisii, such as adhesion of the base of gill lamella, displacement in lamella, swelling and oedema of primary and secondary gill lamella.