Diet and feeding indices of big mouth Botak fish (Cyprinion macrostomum Heckel, 1843) in the Sezar River (Lorestan province)

This study was conducted for identifying the feeding indices of Botak fish (Cyprinion macrostomum) in the Sezar River. Monthly sampling was done from July to December 2011، using pursing net with different mesh size and gill net with 50 mm mesh size. In total 68 specimens of C. macrostomum were examined. The results of feeding indices showed that the mean of RLG was 5. 33±0. 07. Also، the mean of GI، K، IF and CV were 0. 13±0. 002، 1. 41±0. 01، 340. 96±20. 77 and 5. 47، respectively. Based on the results، Navicula، Cymbella، Diatoma and Nitzschia as main، Microspora، Coconeis، Oscillatoria، Pediastrum، Rhoicosphenia، Mougeotia، Tribonema، Synedra، Cosmarium، and Spirogyra as subsidiary and Ulothrix، Gyrosigma، Closterium Scenedesmus، Pinnularia، Gomphonema، Cymatopleura، Diploneis Oedogonium، and Melosira as an accidental food items were detected. Diet analysis showed that Cyprinion macrostomum is a priphyton feeder with a RLG of five processing an appropriate condition factor and feeding condition in the Sezar River.