Investigating the diet of Mossul bleak Alburnus mossulensis (Heckel, 1843) in the Abgarmeh River, Saleh Abad, Ilam Province

This study aimed to determine the feeding habits and diet of Alburnusmossulensis in the Abgarmeh River in Saleh Abad, Ilam Province, in different seasons of 1386-1387.Sampleincludes fifty five A. mossulensis which were caught using Cast net (mouth diameter: 3mm; mesh size: 20mm) and Scoop net (mesh size: 2mm) from 4 stations. The length range of fishes in the sample was 4.70-14.50 cm. In this study obtained the digestive of A.mossulensis were Odonata (138), Diptera (165), Hemiptera (91), Amphipoda (75), Trichoptera (35), Ephemeroptera (95), Coleoptera (62), Oligochaeta (89), Plecoptera (34) and Hirudinea (50) respectively. The highest and lowest abundance of food in the digestive tract were of the Diptera (19.78%) and the Plecoptera (4.07%), respectively. According to the frequency of food groups in the river and the results of digestive tract of fish, it was determined that this fish has tendency to Coleoptera (0.029) and Trichoptera (0.023) and the lowest desire to Amphipoda (-0.053). Average relative length of the intestine (1.095±0.81g) and fullness index of A.mossulensis (946.68±76.97) were higher in spring than those observed in other seasons. Also, the mean condition factor index was higher in winter (795.06±24.99) than that of other seasons. After investigating the gastrointestinal tract it was found that of the 55 cases studied the that all the fish were full stomach. According to the results, A. mossulensis in the Abgarmeh River from Ilam province is a gobbler and omnivorous species who has greatest tendency to Coleoptera and Trichopteraand as its food and the least desire to Amphipoda. This species also has extremely high nutritional.