fa <p style="text-align:justify;text-justify:inter-ideograph;line-height:120%;direction:ltr;unicode-bidi:embed;">Age and growth of Mesopotamian barb, <em>Capoeta damascina</em>, were studied in the Zayandehrud River, in central Iran, from March 2007 to April 2008. Among the 689 specimens studied, age groups in males ranged from 1⁺to 9⁺ and that in females ranged from 1⁺to 10⁺. The sex ratio (1M:1.6F) was not significantly different from 1:1 ratio. Maximum fork length and weight was 39 cm and 1,115 g for males and 54.2 cm and 2,340 g for females. In all age classes, females were larger than males. The most frequent age groups were 3⁺in males and 4⁺ in females. The highest value for condition factor was observed in June. The growth of <em>C. damascina</em> was described by von Bertalanffy growth curve as k=0.01, L_&infin;=56.2 cm, t_o=-0.63 for males and k = 0.05, L_&infin;=117.1 cm and t_{o =}-0.43 years for females. The length-weigh relationship was described as W=0.0169L^2.95(r²=0.98) for males and as W=0.0155L^2.99 (r²=0.99) for females, indicating an isometric growth pattern in both sexes. Growth performance index &phi;` was estimated as 5.73 for males and 6.53 for females, indicating a faster growth rate in females.</p> Ageing, Age at maturity, Cyprinidae, Growth pattern, Von bertalanffy curve, Zayandehrud River. 511 521 http://jifro.ir/browse.php?a_code=A-10-544-6&slc_lang=fa&sid=1 S. Asadollah 100319475328460021985 100319475328460021985 No N.M. Soofiani soofiani@cc.iut.ac.ir 100319475328460021986 100319475328460021986 Yes Y. Keivany 100319475328460021987 100319475328460021987 No R. Hatami 100319475328460021988 100319475328460021988 No