During years 1999-2001, a series of sampling was carried out in Sefidrud River to study morphometric and meristic characteristics of Caspian Vimba. 149 specimens were collected and then necessary measurements were considered and following results were obtained: T.L= 171.2±31.6mm, W= 62.9±19.7g, age= 3.49±0.9 year, average number of scales on lateral line = 50.83±1.8, branched ray of dorsal and anal fins = 7.96±0.2 and 17.58±1.0 respectively. The mean morphometric measurements with respect to body standard length (%) were: head length 24.47±1.9, eye diameter 6.10±1.07, body maximum depth 26.17±1.4, dorsal fin height and length 20.22±1.5 and 10.96±0.8, anal fin height and length 12.66±0.8 and 18.17±1.5, pectoral fin length 18.17±1.2, ventral fin length 14.97±1.1, pecto-ventral fins distance 24.18±l.7 and ventral-anal distance 20.00±1.5 and pre-dorsal distance 52.21±1.7. Adults and juveniles showed difference in 2 meristic and 15 morphometric parameters. On the other hand, the adult males and females showed difference in 16 morphometric parameters (esp. body depth, lengths of dorsal, pectoral, pelvic and anal fins). Also, adult males have a series of fine epithelial tubercles on head and body and their color is darker with more reddish anal and ventral fins
