The aim of this study is to provide necessary information on the age, growth and sex ratio of two important cyprinids species of Barbus brachcephalus caspius and B. capito in the southern Caspian Sea located in the northern part of Iran during 2010-2011. A total of 81 specimens of both species (48 males and 41 females) were collected monthly during 2010-2011. The samples were transferred from landings to the laboratory for further biological measurements and otolith extraction. The maximum age of B. brachycephalus caspius was 5+ (TL= 48.3 cm) and for B. capito was 4+ for a fish with TL= 38.6 cm. The mean TL of sampled B.bracycephalus caspius and B. capito were 27.53±6.13 and 23.38± 4.35 cm, respectively; and the sex ratio were1.0: 0.95 and 1.0: 0.93, respectively. The length-weight relationship estimated for all individuals of both species were as W=0.011TL2.939 (R2= 0.881) and W= 0.004TL3.179 (R2=0.951), respectively. Different regressions were prepared between age and morphological measurements of fish and otolith, of which the highest correlation for B. brachycephalus caspius was between age and otolith weight (g) as a linear regression of OW=0.0005Age + 0.0022 (r= 0.854); and for B. capito showed higher correlation (r=0.955). There was no significant correlation between morphometric measurements for both otolith and fish parameters of B.capito (p> 0.05).
