Considering the reduction of valuable commercial fish in Anzali lagoon during last decades and presence of the silver crucian carp with high frequency; the research project or 'Biological aspects and population dynamics or Carassius auratus" was designed. The study area was stratified to four regions (Abknar, Siah-keshim, Markazi and Sheyjan). Sampling were carried out bi-weekly by using electro-shocker. The mean fork length and mean weight for both sexes were measured 19.5±5.8 cm, and 196.8±137.4 g respectively. Also, the mean age was estimated 2.6±1.3 years (n=750) and minimum and maximum fork length were measured 2.5 and 31.5 cm respectively. The mean length, weight and the age of silver crucian carp in Siah-keshim region were higher than the other regions. The spawning season of this species was found from May to June. The results showed a sex ratio of F:M=99.3:0.7. Some calculated population parameters were as follows: exploitation rate = 0.47, L∞ = 36.0 cm and K = 0.23 per year.