Diet and feeding indices of Garra rufa Heckel, 1843 in Gheshlagh River, Kurdistan Province

This study was conducted to survey the feeding indices of Garra rufa in Gheshlagh River, Kurdistan Province. Seasonal sampling carried out during spring, summer, autumn and winter of 2018 using electrofishing and cast net with 20 mm mesh size. For diet analysis, 40 number of Garra rufa was used. The length and weight of sampled fishes was renged of 56 to 137 cm and 2.5 to 37 g, respectively. The average of RLG index was 8.22±2.25 that specified the herbivory or prephyton feeder. The mean of gastro- somatic index, condition factor (K) and vacuity index (CV) was 11.67±5.28, 1.35±0.23 and 10 respectively. Also, according to the percentage of food groups in the environment and gastrointestinal tract of fish, it was observed that this fish is more inclined to Nitzschia, Gomphonema, Amphora, Cocconeis, Rhabdoderma and Diatoma genera for feeding, respectively and They are the most preferred food items for this fish during the sampling seasons and the genus Ocillatoria with a value of -0.8 had the lowest priority. The genera Cocconeis, Cymbella, Diatoma, Gomphonema, Melosira, Nitzschia, Synedra and Navicula as the main food, The genera Cyclotella, Pediastrum, Stephanodiscus, Cymatopleura, Gyrosigma, Gloeotrichia and Spirulina as the supplementary food and the genera Amphora, Chlorella, Cosmarium, Ocillatoria, Rhabdoderma and Scenedesmus as the incidental food of Garra rufa