identifying the benthic organisms diversity in shahrechay river and dam lake, western azerbaijan province, iran

shahrechay dam is located at 12th km of shahrechay river in urmia. this study was conducted for a year (spring to fall, 2007) to identify different species of benthic organisms in the dam. considering the relevant topographic status like the local depth and water speed, 6 sampling stations were chosen and sampling was done in shallow locations of the river by means of superficial method. in this study, 2 phylums, 2 orders, 13 families and 21 species of benthic organisms were identified in shahrechay dam lake. the results indicated that the highest species diversity belonged to ecdyonuridae family (eperous genus). in terms of frequency, it belonged to tibuficidae (tubifex genus), with 43%, 23%, and 11% ratios for spring, summer, and fall, respectively. the final result of the research demonstrated the poverty of lake bed from view of the benthic quantity and density. therefore, the shahrechay dam was not a suitable candidate to develop fishery’s purposes, especially releasing and growing cyprinidae fishes and other benthos-feeder aquatics.