Investigation on some biological characteristic in Leuciscus cephalus at Babolrud River, Mazandaran Province

This study was carried out in BabolroodRiver ( Mazandaran province) from 5 September 2008 to 6 August 2009 on Leuciscus cephalus ( mahi sephid roodkhanei ). The sampling was montly and samples were collected by Electroshocker. In total 441 numbers of Leuciscus cephalus were caught. Sex ratio of male to female was 1 to 1.41 respectively. The average total length was 165.629.81 mm, within average Maximum in May (190.638.32 mm), and an average Minimum in October (137.526.70 mm). Average Fork length and weight for males was139.7226.49 mm and 43.18 21.58 gr, this value for female was152.8830.06 mm and 57.3227.08 gr respectively. ANOVA results showed significant differences ( P<0.05). Between male and female fork length and weight. Positive regression obtained between fork length and total length showed an R2=.950. Samples belonged to 9 ages groups (0+,1,1+,2,2+,3,3+,4,4+).  Maximum number of fish were in age group 2 and minimum number of  fish were in age group 4+.  Gonad somatic index (GSI) for males was 1.47 ± 0.94, and for females was 2.95 ± 1.83 respectively. The total mean of HSI was evaluated to be 0.73 ± 0.49 for males and 1.08 ± 0.71 for females.According to the present study spawning time was from mid-May to late June and their spawning is batch spawning.