Hadi Asadi - Departman of fishereis, Faculty of Naturnal Resource, University of Guilan
Masoud Sattari - Departman of fishereis, Faculty of Naturnal Resource, University of Guilan
Soheil Eagdari - Departman of fishereis, Faculty of Naturnal Resource, University of Tehran

The rivers of southern Caspian Sea basin are important as spawning sites ofanadromus fishes and pasture of their juveniles from natural reproduction and stockenhancement programs. The Siahrood River, a tributary of the Sefirud River, is apermanent river that is originated from the pristine forest area of the AlborzMountains. This study was conducted to investigate distribution, diversity indices,richness and evenness of fish assemblage of the Siahrood River. Sampling wasperformed by electrofishing in summer and autumn of 2013 at six stations along theriver. In total 455 specimens including 5 species belonged to Cyprinidae, 1 speciesbelonged to Gobiidae, 1 species of Spined loach belonged to Cobitidae and 1 speciesof stream loach belonged to Nemacheilidae were caught and identification and thentheir data were analyzed. Alburnoides eichwaldii had the highest frequency with 128specimens among the stations, especially in the upstream. Diversity indices includingShannon, Margalef and Simpson as well as plot-Rank, K-Dominance, cluster analysisand PCA were calculated for all stations. The results showed that from the upstreamtowards the river estuary, diversity indices is significantly decreased. Due to properconditions of riverine habitat some fish species such as A. eichwaldii inhabit inupstream as dominance species, whereas the downstream has a higher richness dueto various available habitats properties of river.

Diversity index, Siahrood River, Sefidrud River, Caspian Sea basin