Study of some biological parameters and reproduction of theBitterling (Rhodeus amarus) in Sefidrood River, Guilan Province

This study aimed to determine sex ratio, age, growth and reproduction of the populations of R.amarusin Sefidroodriver. In total 189 fish were caught monthly from February to June 2013. Overal sex ratio was 1:1/39. Total weight (W) and total length (TL) was 17/2-71/2mm and 0/06-5/81g, respectively. The condition coefficient of males was higher than females. Growth models in all population were positive allometric for males and females. Fishes in Sefidrood river population had 1 till 9 age group.The average number of eggs was 78.778±33.11. Fecundity (F) with fish total length (TL) and weight (W) had significant correlation. The results of this study would help to increase the information of these species.