Biometrical variation of Artemia urmiana cysts from Urmia Lake (II) (West Azerbaijan, Iran) Alireza Asem1, Nasrullah Rastegar Pouyani 1, Naser Agh 2 1. Department of Biology, Faculty of Science, Razi University, Kermanshah, IRAN 2. Artemia and Aquatic Animals Research Center, Urmia University, Urmia, IRAN Summary: Artemia urmiana has been reported from Urmia Lake by Günter in 1899. The objectives of this study were to investigate the diameter of hydrated, untreated and decapsulated cysts and chorion thickness in 26 stations in Urmia Lake. Tukey Test was used, for analyzing the data. Only 31 pair means of untreated cysts between 26 stations showed significant differences, but, on the other hand, 157 pair mean of decapsulated cysts between 26 stations showed significant differences. Based on this study, there is no variation between diameters of untreated cysts, but a high variation was observed in diameters of decapsulated cysts. For partition of 26 stations, Hierarchical Cluster Analysis was used. (Fig.1) Because diameters of decapsulated cysts showed high variation, mean of diameters of decapsulated cysts and C.V in each station were used in Hierarchical Cluster Analysis. With regard to this analysis, 26 stations are classified into seven categories. Results obtained indicate that diameter of decapsulated cyst is a natural character for the population and environmental factors do not influence it considerably, but it seems that environmental factors do considerably influence the diameter of untreated cysts that include chorion layer too. Therefore it could be finally concluded that biometrical studies of decapsulated cysts could probably be used as a tool for differentiating various Artemia populations. Fig.1- Classification of stations by Hierarchical Cluster Analysis Location of Stations Home