Intra-population variationsin the morphology of Spirlin, Alburnoides eichwaldii (Cypriniformes: Cyprinidae) in Kargan-Rud and Lamir rivers in Guilan province, northern Iran

Spirlin، Alburnoides eichwaldii، is an abundant riverine fish in the south west Caspian Sea basin. Sixty specimens of Spirlin from Kargan-Rud، and Lamir (30 specimens from each river) were studied and compared from morphological point of viewin August 2010. Thirty-one morphometric characters were measured and thirteen meristictraits were countedon each specimen. Nonparametric methods for comparison of means and Principal Component Analysis (PCA) for separation of populations were used. Among the meristic characters، nine characters were significantly different between the four populations (p<0. 05). Among the morphometric and relative morphometric characters، nineteen characters showed significant differences (p<0. 05) between the two populations. In the PCA of meristic characters، three factors accounted for 47. 5% of variations within populations، including; caudal peduncle scales، scale above lateral line and anal fin ray numbers. Within the morphometric characters، three factors accounted for about 71% of variations within the two populations، including dorsal fin height، pectoral fin base، ventral fin length، caudal peduncle depth، head length، inter orbital width، standard length to pre dorsal length، head length to snout length، head length to eye diameter and head length to inter orbital width. The results showed while morphometric and relative morphometric characters were not useful for separating the two populations and sexes، the meristic characters could relatively separate these two populations.