Reproductive characteristics of Siahmahi, Capoeta damascina (family: Cyprinidae) in Beheshtabad river, Tigris basin

A total of 426 specimens of Mesopotamian barb (Siahmahi) Capoeta damascina (Cyprinidae) were caught by gillnets (1–6 cm mesh sizes) from Beheshtabad River, Chaharmahal and Bakhtiari Province from May 2013 to June 2014. Fish specimens were anesthetized in 1% clove oil solution, fixed in 10% buffered formalin and transported to the laboratory for further analyses. Fork lengths of the sampled fish ranged from 8.94 cm to 42.45 (23.32±6.53SD) cm and total weight from 10.3 to 1255.5 (242.5±213.4) g. Based on scale readings, the maximum age was found to be 7+ years for males and 8+ for females. Six reproductive characteristics, viz: sex ratio, Gonadosomatic Index (GSI), Hepatosomatic Index (HSI), relative fecundity, absolute fecundity and ova diameter were determined. The smallest mature male and female were 11.2 and 18.5 cm in fork length respectively. Sex ratio was 1M:0.7F. The GSI showed that spawning occurred from March to June. Oocyte diameters ranged from 0.57 to 2.48 (1.30±0.41) mm. Absolute fecundity ranged between 2260 and 51770 (15360±12030) eggs. Absolute fecundity and fish size (fork length and total weight) were highly correlated. Relative fecundity varied from 11 to 65 (33±12) eggs per gram of total body weight. The average hepatosomatic index was 2.25 ± 0.05 and the highest value was observed in March (3.05 ± 0.31).