Baku, March 10, AZERTAC The Caspian Sea is a unique water body accommodating more than 100 fish species and subspecies, of which only 40 are of any commercial value.Fishing is one of the oldest human occupation. Fishing in the Kura River began about 3,000 years ago. So, 17 centuries ago sturgeon fishing in Azerbaijan was of a commercial nature.Dried fish, fat for cosmetics and glue for technical purposes were produced here.In the 13th Century, Marco Polo tells about the abundance of salmon, sturgeon and other large fish in the Caspian. The Caspian Sea is the only body of water in the world that still has a significant stock of sturgeon, the commercial catch of which here amounts to 90 percent of the world’s total.Most of the Caspian ichthyofauna belongs to sea and river fish, the rest being diadromous and fluvial anadromous. In generally, many species are characterized by a high degree of euryhalinity or in the words, ability to live in a broad salinity range . Such species are predominant by virtue of a particular ionic composition of Caspian Water, resulting from the long period of isolation of the Caspian Sea from World Ocean.