A survey on feeding habits of spirlin (Alburnoides eichwaldii) in Tajan River, Mazandaran province

To study the diet of Spirlin (Alburnoides eichwaldii), samples were caught monthly from three stations in the Tajan River from April 2012 to March 2013. For this purpose, samples of fishes were caught with electroshocker and benthic invertebrates were collected with surbr Sampler. After primary biometry and separation of scales to determine age, their gastrointestinal systems were removed and diets were determined. Vacuity Index (CV) in both sexes in different seasons and at different ages, which proves that Spirlin is among greedy fishes. Mean of relative length of the gut (RLG) in both male and female and at different ages in different seasons are 0.66 and 0.65 respectively (P<0.05), be showed that these species tend to be carnivores. Index of fullness (IF) in both sexes at different seasons of the year, be showed that feeding of Spirlin are not appropriate. This index in different ages be showed with increasing age, rate of the index was decreased (P<0.05). Food preference (FP) in both sexes in different seasons and at different ages showed Trichoptera was main food of this fish. Also, abundance of organisms ingested (P) in all seasons and ages suggests a high abundance of Trichoptera Order in Spirlin’s gut. Rate for all prey were significantly different at all ages (P<0.05). Food selectivity index (E) was positive in all seasons, which represents the Spirlin tend to feed on Trichoptera at all seasons of the year. Condition index (K) in both males and females showed is higher in females than males (P<0.05). This study represents that Trichoptera was dominate and public food of this fish in seasons and different ages.