Investigation of some life history ‎characteristics of Hircan crested ‎loach Paracobitis hircanica ‎‎(Mousavi-Sabet et al., 2015)‎‏ ‏in ‎Zav stream, Golestan National ‎Park, Northern Iran

This study was conducted to investigate life history characteristics of Hircan crested loach (P. hircanica). A total of 150 specimens collected using electro-shocker from December 2015 to May 2016.  Results showed that the sex ratio of male to female is 1:0.65 indicating significant difference of males and females abundance in the studied population (χ2=6.83). The maximum observed total length and weight were 87 mm and 5.30 g for females, 104 mm 7.31 g for males. The weight - length relationship of female was W= 0.0085 TL2.89, of male W= 0.0109 TL2.74 and of the studied population was W= 0.0099 TL2.80. The growth model was isometric for females and negative allometric type for males and the population (t-test, tmale= 6.31, tfemale=1.61, tpopulation= 5.03, P<0.05). The average absolute fecundity was 328.86 per female and the relative fecundity was 110.56 eggs/g of females’ weight. Eggs diameters ranged from 0.45 to 1.79 mm with a mean value of 0.99 mm. The highest mean Gonadosomatic index (GSI) of the females was recorded in April, and of the males in May, indicating the highest reproductive activity of females and males occurs in June and May respectively.