The quality of caviar depends on the conditions in which sturgeon live and the southern part of the Caspian Sea offers them the best.. The northern segment of the Caspian Sea apart from being polluted ,is not very deep and both the sea and the rivers which pour into it are often frozen during several months , due to extremely low temperatures in the winter. However, in the southern segment of the Caspian Sea ,the optimum conditions for the survival and growth of sturgeon and its eggs are found. In this part, the water is not polluted, the sea is much deeper , the temperatures never fall too low and the sea bed structure and water circulation are ideal.

The sturgeon fishing in Iran is carried out by traditional methods. Small wooden boats embark on capturing sturgeon everyday , using simple fishing nets. Sturgeons are immediately taken to the fishing station where they undergo special treatment. Once at the station, they are washed and cut in order to extract the eggs, avoiding any mixing of blood with the eggs. They are then weighed and taken to a laboratory for final treatment.