First report of epibiont communities on Narrow-clawed crayfish, Astacus leptodactylus Eschscholtz, 1823 (Decapoda: Astacidae) from Shiyan dam reservoir, western Iran

This study investigates epibiont communities, including both protozoan and metazoan species, associated with Astacus leptodactylus in the Shiyan Dam reservoir situated in the Kermanshah province of western Iran. A total of 220 crayfish were collected for comprehensive parasitological surveys, targeting various body parts, including the gills, exoskeleton, mouth cavity, and internal organs. Protozoan species identified included Cothurnia sieboldii, Chilodonella sp., Vorticella similis, Zoothamnium sp., and Pyxicola annulata. In the metazoan category, notable species consisted of Branchiobdella kozarovi (Annelida), Philodina acuticornis (Rotatoria), Rabdochona sp. (Nematoda), and Mesocyclops strennus (Copepoda). P. acuticornis exhibited the highest prevalence among gill epibionts at 18.2%, while Chilodonella sp. showed the lowest prevalence at 0.9%. The study also revealed seasonal variations, with the highest infestation occurring in spring (82%), and the lowest in winter (24%). This research presents the first documented evidence of epibionts on A. leptodactylus in western Iran.