Caspian Sea

2007 Schools Wikipedia Selection. Related subjects: General Geography

Caspian Sea
Caspian Sea - The Caspian Sea viewed from orbit
The Caspian Sea viewed from orbit
Coordinates 40°0′N 51°0′E
Lake type Endorheic
Primary sources Volga River
Primary outflows Evaporation
Catchment area 1,400,000 km²
Basin countries Azerbaijan
Russian Federation
Surface area 371,000 km²
Average depth 184 m
Max-depth 1025 m (3363 ft)
Water volume 78,200 km³
Residence time (of lake water) 250 years
Surface elevation -28 m

The Caspian Sea is the largest lake on Earth by both area and volume, with a surface area of 371,000 square kilometres (143,244 mi²) and a volume of 78,200 cubic kilometres (18,761 mi³). It is a landlocked endorheic body of water and lies between Asia and Europe. It has a maximum depth of about 1025 meters (3,363 ft). It is called a sea because when the Romans arrived for their first time, they tasted the water and found it to be salty. It has a salinity of approximately 1.2%, about a third the salinity of sea water.


The Caspian Sea is bordered by Russia ( Dagestan, Kalmykia, Astrakhan Oblast), Azerbaijan, Iran ( Guilan, Mazandaran and Golestan provinces), Turkmenistan ( Balkan Province), and Kazakhstan, with the central Asian steppes to the north and east. On its eastern Turkmen shore is a large embayment, the Garabogazköl.

The sea is connected to the Sea of Azov by the Manych Canal and the Volga-Don Canal.

Cities near the Caspian Sea

Major cities by the Caspian Sea:

The Caspian Sea, viewed from Baku, Republic of Azerbaijan.
The Caspian Sea, viewed from Baku, Republic of Azerbaijan.


  • Bulla
  • Çikil
  • Çilov
  • Gil
  • Nargin
  • Pirallahı
  • Qara Su
  • Qum
  • Səngi Muğan
  • Vulf
  • Zənbil
  • Ashuradeh (Mazandaran)


The sea is estimated to be about 30 million years old. It became landlocked about 5.5 million years ago. Discoveries in the Huto cave near the town of Behshahr, Mazandaran, (Southern land of Caspian Sea) suggest human habitation of the area as early as 75,000 years ago.[ citations needed]

In classical antiquity it was called the Hyrcanian Ocean. It has also been known as the Khazar Sea. In Persian antiquity, as well as in modern Iran, it is known as the Mazandaran Sea. Old Russian sources call it the Khvalyn (Khvalynian) Sea after the Khvalis, inhabitants of Khwarezmia. Ancient Arabic sources refer to Bahr-e-Qazvin – the Qazvin Sea. The word Caspian is derived from the name of the Caspi, an ancient people that lived to the west of the sea in Transcaucasia.

Historical cities by the sea include

  • Hyrcania, Persia (Iran)
  • Tamisheh, Mazandaran, (which is now in Modern Iran)
  • Atil, Khazaria
  • Khazaran
  • Baku, Azerbaijan


An aerial view of the southern Caspian coast as viewed from atop the Alborz mountains in Mazandaran, Iran.
An aerial view of the southern Caspian coast as viewed from atop the Alborz mountains in Mazandaran, Iran.

The Caspian Sea holds great numbers of sturgeon, which yield eggs that are processed into caviar. In recent years overfishing has threatened the sturgeon population to the point that environmentalists advocate banning sturgeon fishing completely until the population recovers. However, prices for sturgeon caviar are so high that fisherman can afford to pay similarly high bribes to authorities to look the other way, making regulations in many locations ineffective.[ citations needed] Caviar harvesting further endangers the fish stocks, since it targets reproductive females.

The Caspian Seal (Phoca caspica, Pusa caspica in some sources) is endemic to the Caspian Sea, one of very few seal species living in inland waters (see also Baikal Seal).

The area has given its name to several species of birds, including the Caspian Gull and the Caspian Tern.

There are several species of fish endemic to the Caspian sea, including Kutum (also known as Caspian White Fish), Caspian Roach, Bream, and a species of salmon. Caspian Salmon is critically endangered.


The area is rich in energy wealth. As well as recently discovered oil fields, large natural gas supplies are also in evidence, though further exploration is needed to define their full potential. Geopolitical jockeying is taking place amongst Caspian-bordering countries, especially in the light of Middle East instability and the subsequent recasting of many Western countries' energy policies. Another factor influencing this is the new US military deployment to the Central Asian region.

A key problem is the status of the Caspian Sea and the establishment of the water boundaries among the five littoral countries. Russia, Azerbaijan and Kazakhstan signed an agreement in 2003 to divide the northern 64% of the sea among themselves, although the other two bordering countries, Iran and Turkmenistan, did not agree to this. This is likely to result in the three agreeing nations proceeding with oil development regardless; Iranian and Turkmen development is likely to stall.

At present, Azerbaijan and Kazakhstan have seen the biggest increase in oil production, an increase of 70% since 1992. Despite this, the region is still achieving less than potential output, with total regional production 1.6 million barrels (250,000 m³) per day, roughly equal to Brazil's production. This is expected to triple by 2010.

The oil in the Caspian basin is estimated to worth in the region of $12 thousand billion dollars.

International disputes

Image:Caspian Borders Old.PNG
Old division of the Caspian Sea
Image:Caspian Borders New.PNG
New division of the Caspian Sea

There are three major issues regulated by the Caspian Sea status: access to mineral resources (oil and natural gas), access for fishing and access to international waters (through Russia's Volga river and the canals connecting it to the Black Sea and Baltic Sea). Access to the Volga-river is particularly important for the landlocked states of Azerbaijan, Kazakhstan and Turkmenistan. This issue is of course sensitive to Russia, because this potential traffic will move through its territory (albeit onto the inland waterways). If a body of water is labeled as Sea then there would be some precedents and international treaties obliging the granting of access permits to foreign vessels. If a body of water is labeled merely as lake then there are no such obligations. Environmental issues are also somewhat connected to the status and borders issue. It should be mentioned that Russia got the bulk of the former Soviet Caspian military fleet (and also currently has the most powerful military presence in the Caspian Sea). Some assets were assigned to Azerbaijan. Kazakhstan and especially Turkmenistan got a very small share (because they lack major port cities).

  • According to a treaty signed between the Persians (predecessor of today's Iran) and the Russian Empire the Caspian Sea is technically a lake and it is to be divided into two sectors (Persian and Russian), but the resources (then mainly fish) would be commonly shared. The line between the two sectors was to be seen as an international border in a common lake (like Lake Albert). Also the Russian sector was sub-divided into administrative sectors of the four littoral republics.
  • After the dissolution of the Soviet Union not all of the newly independent states assumed continuation of the old treaty. At first Russia and Iran announced that they would continue to adhere to the old treaty (but they don't have a common border any more, so this is practically impossible). Kazakhstan, Azerbaijan and Turkmenistan announced that they do not consider themselves parties to this treaty.
  • Later followed some proposals for common agreement between all littoral states about the status of the sea.
    • Azerbaijan, Kazakhstan and Turkmenistan insisted that the sectors should be based on the median line, thus giving each state a share proportional to its Caspian coastline length. Also the sectors would form part of the sovereign territory of the particular state (thus making them international borders and also allowing each state to deal with all resources within its sector as it wishes unilaterally).
    • Iran insisted that the sectors should be such that each state gets a 1/5th share of the whole Caspian Sea. This was advantageous to Iran, because it has a proportionally smaller coastline.
    • Russia proposed a somewhat compromising solution: the seabed (and thus mineral resources) to be divided along sectoral lines (along the two above-described variants), the surface (and thus fishing rights) to be shared between all states (with the following variations: the whole surface to be commonly shared; each state to receive an exclusive zone and one single common zone in the centre to be shared. The second variant is deemed not practical, because of the small size of the whole sea).
  • Current situation

Russia, Kazakhstan and Azerbaijan have agreed to a solution about their sectors. There are no problems between Kazakhstan and Turkmenistan, but the latter is not actively participating, so there is no agreement either. Azerbaijan is at odds with Iran over some oil fields that the both states claim. There have been occasions where Iranian patrol boats have opened fire at vessels sent by Azerbaijan for exploration into the disputed region. There are similar tensions between Azerbaijan and Turkmenistan (the latter claims that the former has pumped more oil than agreed from a field, recognized by both parties as shared). Less acute are the issues between Turkmenistan and Iran. Regardless, the southern part of the sea remains disputed.

    • Russia and Kazakhstan signed a treaty, according to which, they divide the northern part of the Caspian Sea between them into two sectors along the median line. Each sector is an exclusive zone of its state. Thus all resources, seabed and surface are exclusive to the particular state.
    • Russia and Azerbaijan signed a similar treaty about their common border.
    • Kazakhstan and Azerbaijan signed a similar treaty about their common border.
    • Iran doesn't recognize the bilateral agreements between the other littoral states, but this has limited practical implications, because it doesn't have common borders with Russia and Kazakhstan. Also Iran continues to insist on a single multilateral agreement between all five littoral states (as the only way to achieve 1/5-th share).
    • The position of Turkmenistan is unclear.

After Russia adopted the median line sectoral division and the three treaties already signed between some littoral states this is looking like the realistic method for regulating the Caspian borders. The Russian sector is fully defined. The Kazakhstan sector is not fully defined, but is not disputed either. Azerbaijan's, Turkmenistan's and Iran's sectors are not fully defined. It is not clear if the issue of Volga-access to vessels from Azerbaijan and Kazakhstan is covered by their agreements with Russia and also what the conditions are for Volga-access for vessels from Turkmenistan and Iran.

Characteristics and ecology

The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, though it is not a freshwater lake.

The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it is endorheic, i.e. there is no natural outflow (other than by evaporation) except the Manych Canal. Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans. The Caspian became landlocked about 5.5 million years ago. The level of the Caspian has fallen and risen, often rapidly, many times over the centuries. Some Russian historians claim that a medieval rising of the Caspian caused the coastal towns of Khazaria, such as Atil, to flood. In 2004, the water level is -28 metres, or 28 metres (92 feet) below sea level.

Over the centuries, Caspian Sea levels have changed in synchronicity with the estimated discharge of the Volga, which in turn depends on rainfall levels in its vast catchment basin. Precipitation is related to variations in the amount of North Atlantic depressions that reach the interior, and they in turn are affected by cycles of the North Atlantic Oscillation. Thus levels in the Caspian sea relate to atmospheric conditions in the North Atlantic thousands of miles to the north and west. These factors make the Caspian Sea a valuable place to study the causes and effects of global climate change.

The last short-term sea-level cycle started with a sea-level fall of 3 m from 1929 to 1977, followed by a rise of 3 m from 1977 until 1995. Since then smaller oscillations have taken place . These changes have caused major environmental problems .


Several scheduled ferry services operate on the Caspian Sea, including:

  • line between Turkmenbashi, Turkmenistan (formerly Krasnovodsk) and Baku
  • line between Baku and Aktau


The northern part of the Caspian Sea freezes during winter. In the coldest winters ice can also be found at south. When weather is not as harsh icebanks can form in the shallow waters neighbouring the coast.

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