OTOLITH MORPHOLOGY OF SOME FRESHWATER FISHES OF IRAN

Otoliths or ear stones are small white bodies present in the ear of bony fishes. Otoliths are important in keeping fish position and steadiness and also are useful structures in hearing. There are three pairs of otoliths which are called Sagittus, Lapillus and Astriscus. In the present study, otoliths of 15 species belonging to 14 genera and 6 families were collected from different basins including Kor Watershed, (Ghadamgah), Persian Gulf (Ghara Aghaj River), Hormuz (Khurgu Hot Spring), Tigris and Karon (Ghaghakhor wetland) and also some fish farms of Fars province were examined. Results showed that in Salmonidae, Cichlidae and Cyprinodontidae families Sagittus is larger while in the Balitoridae, Cobitidae and Cyprinidae Asteriscus is bigger than the other otoliths. Moreover, there is high variation in Asteriscus shape in different families.