Caspian Sea is regarded as the largest inland body of water in the world. It is also known as a brackish body of water. With a total surface area of 371000 square kilometers, length of 1030 km and a width of 435 to 200 km, the Caspian Sea has been the rich sources of fish particularly the sturgeon and its valuable caviar. Approximately 90% of the world’s caviar come from the Caspian Sea.

The Caspian basin is generally divided into the northern, middle, and southern Caspian which is bordered by five countries Azerbaijan to the west, Iran to the south, Turkmenistan to the southeast, and Kazakhstan and Russia to the northeast and northwest, respectively. More than 130 rivers flow into the Caspian and supply its fresh water. Among these rivers, the Volga River and the Ural River are the most significant rivers.

Since the Caspian Sea is landlocked, it is good to understand that it has freshwater sources and also isn’t connected to salt-water of the open seas of the world. This is the reason why the mean salinity of the Caspian is one third that of Earth’s oceans. Overall, Iran has the most saline shore due to its brackish basin.

As mentioned before, the southern region of the Caspian Sea is near Iran which is less polluted because this region is characterized by the deepest part of Caspian Sea with oceanic depths of over 1,000 meters. Today, Iranian caviar comes from the northern Gilan, Mazandaran, and Golestan provinces bordering the Caspian Sea. Along with other species of sturgeon, the Caspian Beluga caviar has the most delicate and unique taste of all sturgeon caviar due to the icy brackish waters.