The Caspian is shallowing: results of a spring expedition

In April, 2026, New Delta-2026, a marine scientific and geographical expedition, took place. It was organised by P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences (IO RAS) and Astrakhanskiy State Nature Biosphere Reserve, with the support of Caspian Flotilla Hydrographic Service. Researches were conducted on the Volga-Caspian Shipping Canal and in the northern Caspian Sea.

Geomorphological observations yielded operational data on changes in the sea coastline. Coastline growth was detected on existing and newly forming islands. For example, the area of Chistoy Banki Island was doubled (compared to 2019) due to a decline in the Caspian Sea level. New zones were become shallower on its eastern, western, and southern sides. A rapid increase in the area of an island formed on Tbilisi Bank was also been observed, having expanded three times (compared to 2025).

During the expedition, samples were collected to determine hydrochemical parameters in laboratory conditions. Current meters’ recordings revealed a back-and-forth movement of water masses in a southwest – northeast direction, which was related to the redistribution of river waters entering the northern Caspian and synoptic conditions.

These comprehensive researches provided up-to-date data on the state of the Caspian Sea and confirmed the trend of progressive decline in the Caspian Sea level.

The news is devastating for survival of the Caspian seal. This endangered species continues to lose an important marine area for breeding. For more information, read our press release (here).

Source: P.P. Shirshov Institute of Oceanology RAS.
Photos by Lisitsyn S.A., Kostyanoy A.G., Ermakov I.D. – specialists of IO RAS.