The changes in biological structure and growth common kilka were investigation during 2008-2017 in the Iranian waters of the Caspian Sea. Kilka fishing ships discharged theirs catch in three ports : Babolsar, Amirabad and Anzali. The sample based on the length of 5 mm were classified class. Fork length ranged from 52.5 to 142.5 mm and mean (±SD) 101.9±10.5 and fish fork length 92.5-112.5 mm of the population have been dominant (81%)(n= 49759). The slight fluctuations in the average length with values ​​between 100 and 105 mm. During this period, fish of +3 and +4 years old have been dominant with frequency of 80-70%. The stability  length and weighted mean of generation growth rate was indicative of relative stability and the average age of common kilka stability, the stability of the population are descendants entered and confirmed. 

The results showed that in the year 2008 the frequency of young fish 1-2 years was 15.2% of the catch, but gradually in the following years, the abundance of these fish in the hake decreased, so that in 2017, only 10% of the catches were allocated. Reducing overfishing and pressure on young fish stocks is an opportunity to rehabilitate stocks of this species.