Effect of biological and environmental conditions on the catch rate and migration of Rutilus Frisii Kutum in the southeast basin of the Caspian Sea (Golestan Province)

To study the biological effects of environmental factors on fish and white fish migration Caspian Sea (Rutilus frisii kutum) in the pre-op area Miankaleh (Golestan Province), sampled from 20 October 1392 to 30 April 1393 was conducted . Hunting by cooperatives blade (net blockade) in the study was performed. Most of the catch per unit effort (one step seine operations per day) white fish was in March. Whitefish from 1 to 8 years of age distribution of the age groups 5-3 years, in total, about 2/81 of a combination of age, respectively. The maximum weight of the fish abundance, between 750-450 grams, which is 85/35% of white fish in the 6 month study, devoted to the study Antayj white fish stocks over the past decades in terms of slightly increased found significant. But in terms of qualitative changes in the store, we see that the most important low growth factors such as length, weight and age white fish than a decade ago. The concentration and distribution of the fish to migrate, to a large extent dependent on physical conditions such as temperature, sea currents, substrate and type of wind that stimulate fish to migrate and spawn in the south-eastern shore of the Sea Caspian is very effective.