عنوان مقاله [English]
The Qezel Owzan River is one of the most important rivers in Zanjan province. The main purpose of the study was determination of fish diversity and abundance. The samples were taken from 5 stations. The study started in 2008 and lasted in 2009. The instruments used for catching the samples were electroshock, cast net, and dip net. Results showed that 10 fish species belong to 2 families: minnows (Cyprinidae) and hillstream loaches (Balitoridae) which exist in the river, so Cyprinidae with 7 genus and 9 species and maximum abundance of (98.2%) is prevalent, while Balitoridae had only one species. Capoeta capoeta gracilis was prevalent in 3 seasons and in three stations namely satations 3, 4, and 5. On the other hand, Alburnoides bipunctatus were seen just in 1 season and in the 1st and 2nd stations. In addition, C. capoeta gracilis, A.bipunctatus, B.capito with the abundance of 33.6, 22.1 and 13.1 % of total number of caught fishes in the study were respectively abundant. In this study the least diversity (4 species) was observed in 3 stations and the most diversity (10 species) in downstream station(S 1).