The analysis carried out by zoologists showed that in the Aral Sea, mainly a small amount of marine oceanic species, and a huge complex of brackish-water groups, up to of the Caspian-estuary fauna, here it was destroyed.

    The eastern half of the united Aral-Caspian Sea had, in their opinion, in as the border of the former Karakum Bay chink of the Unguzov coastline. This united sea covered a wide strip of the modern Caspian Sea up to the foot of the western spurs of the Kopetdag and connected with the Karakum and Chilmetkum bays through two straits - the Greater and the Lesser Balkh. The Aral part flooded the entire Sarykamysh basin during the same period and formed up to Pitnyak bay, now occupied by the modern delta of the Amu Darya and the Khiva oasis (by the way, this explains shor deposits at Pitnyak).
   The results of these works were summarized in 1908. L. Berg in his famous work “Essay on the history of the Aral Sea research”, where he states, that none of the Greek and Roman authors had a direct or indirect mention of Aral Sea, but many of them talk about Oksa (Amu Darya) and Aksart (Syr Darya), it is not clear where falling in. According to the famous Khorezm scholar Al Beruni, who died in 1048, Khorezmians leading their chronology from 1292 to the birth of Christ testify to the existence of the Aral Sea.
   Uzboy was a strait that connected both of these water areas, but, obviously, its current form with large slopes was formed as the Caspian Sea was separated from the Aral Sea and mark difference between them. During the subsequent geological period up to the present day, there was the division of the united Aral-Caspian basin into its component parts and its gradual reduction to the current limits. First, a watershed appeared between the Aral-Sarykamysh and the Caspian at Balla Ishem on Ustyurt, then the channel of Uzboy gradually appeared.