Evaluation of the Diet of Juveniles Roach (Rutilus caspicus) in Earthen Ponds of Syjwal Bony Fish Breeding Center

This research was conducted to evaluate the diet of juvenile roach (Rutilus caspicus) stocked in earthen ponds and improve the pond conditions to increase the dominant organisms species. Four earthen ponds with the same hydrobiological properties were studied in the Syjwal bony fish farm. Sampling of the food organisms, measuring the weight and length of the juvenile roaches, and gut examination were carried out over a four-month period from March to June. The results indicated that the highest and the lowest condition factors (K) were 1.196 and 0.633, respectively; while the highest dominance index (Ip) was reported as 42.14 for Gastropoda and the lowest dominance index was reported as 2.4 for aquatic insects. The results of (Fp) analysis showed that the gastropoda and crayfish were mainly considered as the major preys, and organisms such as aquatic insects and bivalves were found as the minor foods in the Syjwal earthen ponds. Evaluation of the food preference (Fp)and the gut content of juvenile roaches in different stages indicate that the gastropoda show a higher food preference and feeding intensity than the other Foods.