Survey on the metazoan parasites in Neogobius fishes from Southeastern part of the Caspian Sea

In this study a parasitological investigation on 238 samples of Neogobius species from the south-east of Caspian Sea was carried out. The samples including Neogobius melanostomus (35), N. fluviatilis pallasi (103), N. kessleri gorlap (70) and N. bathybius (30) were seasonally seined by beach net during one year (summer 2006-spring 2007), fixed in 10 % buffer formalinand transferred to the laboratory. From 231 of examined fishes 235 specimens were infected (97/6 %). The collected parasites were as follows: Hysterothylacium aduncum, Raphidascaris acus, Cucullanus sphaerocephalus, Dichelyne minutus, Raphidascaroides sp., Cystidicola sp,. Gyrodactylus sp., and Corynosoma strumosum. Hereby, N.melanostomus is introduced as a new host for Raphidascaroides sp., C. sphaerocephalus and Cystidicola sp.. N. fluviatilis pallasi and N. kessleri gorlap for C. sphaerocephalus, Cystidicola sp. and H .adunacum. N. bathybius for C. sphaerocephalus, Cystidicola sp., H. aduncum, E.excisus, R. acus and C. strumosum. Cystidicola sp. and H. adunacum were reported for the first time from Iran. Among the investigated fishes N. fluviatilis pallasi possessed the highest and N. bathybius the lowest variety in infection with various species of parasites. The results of this study indicated that there are significant relations between total length (T.L.) and weight in N. fluviatilis pallasi with the number of C. sphaerocephalus, D. minutus and E. excises. Also there are significant relations between total length and weight in N. melanostomus and between weights in N. kessleri gorlap with the number of C. sphaerocephalus.