Reproduction of Capoeta damascina (Valenciennes, 1842), a cyprinid fish, in Zayandeh‐Roud River, Iran

Summary Reproductive characteristics of siahmahi, Capoeta damascina (Valenciennes, 1842), a native cyprinid in the Zayandeh‐Roud River, were investigated by monthly sampling from March 2007 to April 2008. Among 689 specimens captured, the overall sex ratio was 1 : 1.57 (males : females). Males matured at age 2 + . Females matured between ages 4 and 6, with 100% maturity at age 7 + . Based on the gonadosomatic index (GSI), the reproductive period peaked between May and June. Histological and macroscopic characteristics of the gonad indicated the species to be group‐synchronous. Absolute fecundity varied greatly with female size, ranging 2520 to 72 650 (mean 24 800 ± 17 800) eggs for females 25.5–54.2 cm TL and weighing 320–2340 g. Fecundity increased with fish age, averages being 9446 ± 8028 for 4 + old females and 54 503 ± 13 803 eggs in mature 8 + year old females.