و ماهی)Petroleuciscus esfahani(تغییرات فصل ی رژی م غذایی عروسما هی اصفهان ی در رودخانه زایندهرود)Chondrostoma regium(نازک

In this study, seasonal changes in the diet of Petroleuciscus esfahani and Chondrostoma regium were investigated by collecting 200 samples of each species seasonally in 2013 from the Zayanndehroud River. The indicators of frequency occurrence index, numerical importance index and abundance of benthic organisms were used to determine the importance of food groups. In the current study, 7 classes, 11 orders and 33 families were identified along with other particles including filamentous algae, sediment particles and plant detritius in the intestine of P. esfahani and C. regium, most of which were aquatic insect larvae. The identified groups were related to Annelida (Oligochaeta and Hirudinea), Arthropoda (Crustacea, Insecta and Arachnids) and Mollusca (Bivalves and Gastropoda). The results showed that the highest presence of food groups in the intestines of the P. esfahani was related to Insecta and the least was related to Gastropoda and plant detritius. In the intestines of C. regium in spring, Insects and unknown food groups, in summer, Filamentous algae and Gastropoda, in autumn, filamentous algae and plant detritius, and in winter, Insecta and sediment particles were the most and least abundant, respectively. In general, it can be concluded that Insecta had the highest percentage of importance in both P. esfahani and C. regium, and the diets of these two fish in the Zainderud River are based on feeding on insects. [ABSTRACT FROM AUTHOR]