Ectoparasitism on freshwater fish in West Azerbaijan, northwest of Iran

Ectoparasites are considered as one of the most important pathogens threatening fish health and production. Due to importance of freshwater fish as a main source of food and income and also little accessible information regarding the serious infectious agents, especially ectoparasites, in fish, the present study was carried out to determine and identify ectoparasite infestations in fish species in water resources of West Azerbaijan province, the northwest of Iran. Between June 2015 and January 2017, 280 freshwater fish belonging to families Cyprinidae and Salmonidae were collected and transferred to the laboratory to inspect for ectoparasites. For this purpose, the whole surface of the body (including skin, fins, and gills) was carefully checked and the isolated parasites were identified under stereo and light microscope. The results revealed that 162 (57.9%) of examined fish including 96 (60.7%) cyprinid and 66 (54.1%) salmonid were infested with four species of ectoparasites consisting of two types of monogeneans, one protozoan and arthropod. The collected parasites were as follows: Icthyophthirius multifiliis (28.2%), Argulus sp. (7.8%), Dactylogyrus spp. (22.1%), and Gyrodactylus sp. (14.3%). The present study reported important results about the species and prevalence of ectoparasites infesting freshwater in the study area. Further studies are required to evaluate the prevalence of various types of parasites in fish in the study area with focus on fish-borne parasitic diseases.