Reproductive biology of Alburnus mossulensis (Teleostei: Cyprinidae) in Gamasiab River, western Iran

In the present investigation, some reproductive characteristics of Alburnus mossulensis were examined. Sampling of 325 specimens were carried out at monthly intervals from Gamasiab River, Tigris River drainage, western Iran, through the year 2013. Age, sex ratio, fecundity, oocytes diameter, gonadosomatic (GSI), modified gonadosomatic, Dobriyal and hepatosomatic indices were measured. Regression analysis was used to estimate the relations between fecundity and standard length, body weight, gonad weight and age. All of the male with 70.0mm and female with 75.0mm in standard length, and all of those older than one year were ripe. The mean egg diameter ranged from 0.11mm (August) to 0.84mm (May). Spawning took place in May, when the water temperature was 18 to 22°C. Average GSI values for females at the beginning of the reproduction period (March) and in ripe mature females (May) were 5.05% and 12.03%, respectively. The averages of absolute and relative fecundity (g/body weight) were 1920 eggs (±1025SD) and 99.03 (±94), respectively. The absolute fecundity was significantly related to body length and ovary weight.