Parasites of stellate sturgeon (Acipenser stellatus) from south-west of Caspian Sea

Sturgeons are the most important fishes of Caspian Sea, but there are few reports about the pathogens of them in southern part of the Sea. in this survey, it has been attempted to indicate the parasite communities of Acipenser steflatus and their prevalence as well as their effects on the fish growth. In this survey 234 A. steflatus were caught from three different geographical locations including fisheries sections I. ii and a hatchery adjucent to Sephid Rud River (ill) in south -west of Caspian Sea (Guilan Province. iran).Common parasitology procedures were used for necropsy of the fish and recovery of parasites. The parasites were fixed in Buffererd Formalin (10%) and ethyl alcohol (70%), stained by Acetocarmine and then identified. Standard statistical computations (mean, Standard Deviation, range, prevalence and dominance) were calculated for the overall samples and for samples grouped by geographical location. The differences between groups defined by Z test and One Way Anova test (p<0.05). Nine different parasite species wererecovered from internal organs of the fishincluding Skrjabinopsoius semiarmatus (preva|ence= p = 43.15%). Leptorhynchoides plagicephaius (p = 20.18%). Cuculianus sphaerocephaius (,0:17.26%}, Eubothrium acipenserfnum (p=9.14%), Bothrimonus faflax (p = 4.47%), Eustrongylides excisus (larvae), Anisakis sp. (larvae), Amphilina foiiacea and Corynosoma strumosum. The prevalence and intensity of parasites in fisheries section of ii and III were more than section I. A direct relation was found between some parasites(especially 8 .semr'armatus) and size. The prevalence and intensity of some parasites in females were more than males and also it was found that there is a correlation between some parasites (especially 3. semiamiatus) and season. in this survey, again it was found that the internal parasites of A. steliatus in this area (south ~ west) are the same as northern part of Caspian Sea but the diversity of parasites was less than north. Furthermore, the diversity of parasites has been decreased in a period of time (compared with the first survey), though the prevalence and intensity of some (marine) parasites appears to be increased during this period.