Investigation on relative frequency of some protozoan ectoparasites infestation in Hemiculter leucisculus and Abramis brama orientalisis fishes of Anzali lagoon

Anzali lagoon is the most significant support for the Caspian Sea fishes that come for laying eggs and breeding. Monitoring certain parameters indices such as metabolic، pathologic or parasitic indicators could be used as a useful، economical and reliable indicator to determine the effects of pollutants on the ecosystem. Therefore، mostly ectoparasitesare necessary characteristics for a parasite species to be used as a pollution indicator. Hemiculter leucisculus is a native fish and Abramis brama orientalis is a migrant of the Anzali lagoon. In order to identify the contamination rates and investigate the average of pollution 150 Abramis bramaorientalisi and 200 Hemiculter leucisculus from five stations transported to the central lab. From all areas including; fin، skin surface and gill samples was taken for investigation. Found parasitic protozoan are: Trichodina that in Abramis bramaorientalis fish its rate was 33. 27%، and in Hemi was 21 %، this parasite was on the skin and gill of the fish، in fact the highest rate of infection was associated to this parasite. Ichthyophthrius; its infection rate among Abramis bramaorientalis fishes was 19. 33% and 19. 5% among Hemiculter leucisculus fishes. This parasite is positioned on the skins surface and gill، after the survey there was no sign of infection in blood sample. Chilodonella was 18% among Abramis bramaorientalis، fish and 14. 5% among Hemiculter leucisculus fish. Ichtyobodo was 15. 33% among Abramis bramaorientalis and 17% among Hemiculter leucisculus fish. Ectoparasites are more obedient to water environment conditions compared by internal ones. In five sampling places، the northern region of the central district in Anzali lagoon، the highest contamination load is concerned with Pirbazar River that the infection caused by protozoan ectoparasite is more intense.