Caspian Sea Day is celebrated on August 12, the day the Tehran Convention, signed by Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan in 2006, came into force. The Caspian Sea is the largest enclosed body of water on the planet, home to beluga, sturgeon, stellate sturgeon, and the world's only Caspian seal. However, today's celebration is taking place amid alarming news: the sea is rapidly shrinking. Scientists at the Institute of Oceanology of the Russian Academy of Sciences have recorded that since 1996, the Caspian Sea's surface area has shrunk by 7.4%—an area comparable to Albania. The rate of sea level decline has almost tripled, from 8 to 22 cm per year. How this shallowing is changing the ecosystem, the Volga Delta, shipping, and fish stocks—in our article.
Caspian Sea level drop: the sea's area has decreased by 28,644 km²
Scientists from Shirshov Institute of Oceanology of the Russian Academy of Sciences, together with colleagues from the Geophysical Center of the Russian Academy of Sciences and Tver State University, conducted a large-scale study of changes in the Caspian Sea area from 1993 to 2025. The results, supported by a grant from the Russian Science Foundation (RSF), demonstrated the scale of environmental transformations.
As researchers note, the Caspian Sea level has been falling since 1995. In 2025, it dropped to -29.4 meters, which is already lower than the historical minimum of 1977 (-29.0 m).
"From 1996 to 2025, the Caspian Sea's surface area decreased by 28,644 km²—7.4% of its 1996 size. This figure is comparable to the territory of Albania. While sea level declined at an average rate of 8.16 cm per year from 2005 to 2019, this rate increased to 22.7 cm per year from 2020 to 2024," commented Professor Andrey Kostyanoy, lead researcher at the Institute of Oceanology of the Russian Academy of Sciences and the study's leader.
According to scientists, falling sea levels are causing a whole host of negative consequences: the coastline is becoming exposed, the sea is receding from populated areas, and the shallowing of the Volga-Caspian Shipping Channel and ports is seriously complicating shipping.
Shallowing Caspian Sea: How the Volga Delta is moving toward the sea and islands are disappearing
The drop in sea level directly affects the main “water intake” of the Caspian Sea - the large Volga delta, where three sections of the Astrakhan State Nature Reserve are located.
According to specialists from the Astrakhan Biosphere Reserve, the delta front is becoming shallower and rapidly overgrown, causing the disappearance of valuable shallow areas essential for fish nurseries. The surface portion of the delta is inexorably moving seaward, forming new land, causing the most productive areas for waterfowl to shift beyond the boundaries of protected areas.
The reserve also conducts continuous monitoring of the Northern Caspian, paying particular attention to the federal natural monument of Maly Zhemchuzhny Island.
"Although the island is called 'Small,' it is very important for the natural environment of the Northern Caspian. For many years, it has served as a permanent nesting site for a large colony of gulls—the Great Black-headed Gull, Caspian Tern, Caspian Gull, and Sandhill Tern (in some seasons, over 40,000 pairs). Dalmatian pelicans also nest here, and Caspian seals are concentrated here. In recent years, a significant decline in the Caspian seal population has been observed, and the Astrakhan Nature Reserve is helping to develop a concept for saving this unique seal species," the Astrakhan Nature Reserve notes.
On Caspian Day, the reserve's staff is holding educational events: an environmental education festival is taking place at the Yunost Children's Aid Center, and an exhibition of children's drawings dedicated to the delta's symbol, the lotus nucifera, will soon be openned.
Caspian Sea Fisheries: Results of the KaspNIRKh Research Voyage
Despite climate challenges, science is actively working to preserve the sea's biological resources. In the first half of July 2026, specialists from the Volga-Caspian branch of VNIRO (CaspNIRKh) completed a research voyage on the vessel Raisa Khodorevskaya in the northern Caspian Sea.
Scientists conducted a comprehensive inventory of bioresources: they assessed trawl catches, the hydrochemical composition of the water, bottom sediments, and conducted a route census of seals.
The researchers' catches were dominated by semi-anadromous species—roach, bream, asp, and pike-perch—and, among the marine species, sprat, herring, and gobies. At some stations, crayfish were recorded, as well as the occasional sighting of the extremely rare Russian sturgeon.
The collected data will allow scientists to more accurately assess current aquatic bioresource stocks, calculate permissible catch volumes, and develop scientifically based measures to protect the Caspian Sea.
Recreational fishing in the Caspian Sea: monitoring and restoration of activity
Meanwhile, specialists from KaspNIRKh are summing up the results of their recreational fishing monitoring in the Astrakhan Region. In July 2026, the region recorded the lowest number of recreational fishermen in all of its years of monitoring. Fuel shortages and increased water discharges from the Volgograd Hydroelectric Power Station in July impacted tourist activity. The rising water level flooded traditional campsites, increased the water velocity, and increased the amount of trash.
However, fishing activity has already begun to rapidly recover since August. There is some good news for environmentalists: specialists have noted a high number of young-of-the-year pike (the young have reached 25 cm in length and 150 g in weight), indicating favorable conditions for the reproduction of this predator.
How to save the Caspian Sea: climate, science and the common efforts of five countries
The causes of the Caspian Sea's cyclical fluctuations are still a subject of scientific debate, but most researchers agree that global climate change underlies the processes.
Protecting the Caspian Sea from complete depletion and adapting to new realities is only possible through the combined efforts of environmentalists, scientists from five countries, and the residents of the Caspian region themselves. Happy holiday to all who study, protect, and love our unique Caspian Sea!
