10 Caspian Sea Facts You Must Not Be Aware Of

The Caspian Sea lies in Eastern Europe, at the border between Europe and Central Asia. As the largest inland body of water on Earth, it has been vital to the economy of the surrounding regions. The Caspian sea was formed 30 million years ago, around the same time as the Black Sea and the Aral sea.

However, it faces the adverse effects of climatic changes and pollution. Also, the construction of dams and other activities have created an imbalance. The Caspian sea levels have been rising since the mid-1950s, and in 1977, massive floods destroyed the coastal regions.

With a wealth of marine flora and fauna, the Caspian Sea covers nearly 0.4 million square kilometres of area and has an average depth of over 1 kilometre. It spans 7,000 kilometres of coastline, covering five different nations on both continents.

Numerous islands dot the Caspian’s surface, and the Sea is 28 m below the mean sea level. The Caspian is considered an endorheic basin, i.e., it has no primary outflow and retains water.

The primary means of water loss is through the water cycle (evaporation and other natural phenomena) and certain sub-surface geological rifts and depressions. The rivers that provide this inflow to the Caspian Sea are the Volga rivers, the Ural river, the Kura, and the Terek rivers.

caspian sea

10 Interesting Facts About the Caspian Sea

This article looks at ten interesting facts about the Caspian Sea. It has immense historical and geographical significance and is considered a major energy source for the surrounding nations.

1. The Caspian Sea has a long history and many derivations of its name

A long-standing theory behind the name “Caspian” is that it refers to the Caspi people in the 6th century BC, who were native inhabitants of the region. They lived in the South West and were of Irani or Persian descent.

While not much literature exists on their exact culture, they have been mentioned in Egyptian, Persian, and Greek chronicles. The region they inhabited was known as Transcaucasia and was at the junction between Europe and Asia. This translates to modern-day Georgia, Armenia, and Azerbaijan.

The region of Iran has also greatly contributed to the lore and history of the Caspian Sea region. The fabled “Gates of Alexander” or “Caspian Gates” were barriers said to have been erected by the Macedonian conqueror- Alexander the Great, to keep barbarians from invading the territory to the South. It is supposed to lie in modern-day Tehran.

Interestingly, the Iranian city- of Qazvin is said to be the original regional name for the Caspian Sea. The water body was recorded as the “Bahr Qazvin” in antiquity by local Arabs. This translates to the “Sea of Qazvin”, which was corrupted to Caspian later on.

It was also known as the Hyrcanian Ocean and the Khazar Sea in ancient times. In Persia and modern Iran, it is known as the Mazandaran Sea. Russian manuscripts dating to the 16th century called it the Khvalynian Sea after the Khvalis, people of Khwarezmia.

The local name for the Caspian Sea in all neighbouring regions stemmed from the common root. For instance:
– Russian, Kaspiyskoye More
– Kyrgyz (the language of Kirghizstan), Kaspiy denizi
– Kazakh, Kaspiy tenizi

2. The Caspian Sea is the world’s largest inland body

The Caspian covers 371,000 square kilometres and is considered the largest inland lake due to its sheer proportions. It is huge owing to the inflow from several major rivers and reservoirs. It has an average elevation of 28 m below the mean sea level.

Interestingly, the Caspian Sea has not historically been large or even an inland land-locked lake. Until 11 million years ago, the Caspian Sea was connected to neighbouring water bodies such as the Black Sea and the Mediterranean Sea.

The connecting body of water was known as the Sea of Azov and linked to the “World Ocean”. The world ocean concept is that all Earth’s water bodies are interlinked by lakes, straits, rivers, etc.

Today, the Caspian Sea is relatively isolated and is only linked via the inflow of rivers. The Sea has become the largest inland water body with minimal outflow regions.

3. The seabed is the 2nd lowest natural relief depression on Earth

The seabed of the Caspian Sea is varied in depth and sub-surface features. The depth of the Sea increases as one moves South. The North Caspian region covers less than 100,000 square kilometres and has an average depth of around 10 meters, with a maximum depth of 20 meters.

However, the South is considerably deeper, with an average depth of over 1,000 meters. A region of 1,023 meters deep in the South makes the Caspian Sea the 2nd lowest natural relief depression. The first is Lake Baikal in Southern Siberia, which has a depth of 1,180 meters.

The seabed of the Caspian is generally flat in the North. Specific rapid elevations have formed the base for the islands in the Sea. Further towards the middle of the Sea lies the Mangyshlak Bank of the Middle Caspian, spanning over 137,000 square kilometres.

This Bank has uneven depressions, and the mean depth is over 200 meters. Further South lies the Abseron Bank that marks the Southern Caspian. It spans 149,000 square kilometres and has a deep depression with an average depth of 500 meters and a maximum depth of 1,023 kilometres.

The Caspian sea has a subtropical continental climate and a complex circulation pattern.

4. The seabed of the Caspian Sea holds clues to plate tectonics and geological phenomena

The Caspian Sea was initially above land about 11 million years ago. The changing geology was also evident as it submerged in the region’s rocks. This has helped scientists to understand plate tectonics and advanced geological phenomena.

The North Caspian region dates back over 500 million years to the Precambrian era. It is part of the Russian Platform down warp formation. The Mangyshlak Bank is part of an ancient sub-surface movement that created the Hercynian mountains over 300 million years ago.

Due to the vast size of these continental plates, a depression was created in the middle nearly 250 million years ago, making the Southern Caspian. The Abseron Bank was directly related to the Alpine process from 25 million years ago. This process resulted in the creation of the Caucasus mountain range.

As per geological studies in the region, the Southern parts of the seabed continue to shift due to tectonic activity. An interesting fact is that the Caspian Sea was connected to the Black Sea by a submarine feature known as the Kuma-Manych Depression. This connecting subterranean water body existed until around 14 million years ago. After that, a tectonic lift resulted in this depression closing. Today, the Caspian is almost entirely landlocked.

5. It is home to several unique species of marine fauna

As an inland lake, the Caspian Sea is home to numerous indigenous marine flora and fauna species. Most of these are protected species to prevent ecological damage.

Through archaeological surveys, researchers have identified possible evidence of dolphins, porpoises, and whales in the Sea around 50,000 – 100,000 years ago.

There have also been cave and rock arts dating to the same period indicating reliefs of dolphins and whales. These ancestors to the modern-day species were considerably larger.

Due to internal currents, species from the Caspian often reach other water bodies, where they quickly become invasive. One such example is the Zebra mussel from the Caspian-Black region that has now spread to nearby coasts.

On the other hand, numerous species have slowly been driven to extinction or endangerment owing to hunting. The Caspian seal, native to the region, numbers only around 100,000 today, when there were initially over 1 million in the early 1900s.

Some species unique to the Sea have been prefixed with the term “Caspian” to indicate their origin. This includes the Caspian tern, Caspian gull, Caspian turtle, Caspian seal, Caspian white fish and Caspian salmon.

6. The Caspian Sea has large oil reserves and several rigs in the region

The countries bordering the Caspian Sea depend on its mineral resources, including oil and natural gas reserves. This contributes to an estimated 10% of their GDP and around 40% of all exports.

These countries organized the Caspian Economic Forum in 2019 to strengthen their inter-governmental relations and improve coordinated efforts in diverse fields such as infrastructure, oil & gas, tourism, trade, and transport.

These nations are Azerbaijan and Kazakhstan, attracting Foreign Direct Investment (FDI) to their energy sector.

Iran has an ample supply of crude oil and is ranked 2nd in the world in terms of reserves. It has an estimated 137.5 billion barrels of crude oil and 988.4 trillion cubic feet of natural gas. Russia is ranked 2nd in the world for oil and natural gas production.

The average output from the Caspian Sea is 1.4 – 1.5 million barrels per day. Kazakhstan produces 55% and Azerbaijan 20% of the production. Exploration of the seabed and construction of oil wells can be traced back to the late 19th century in the Bibi-Hey bat Bay of Azerbaijan.

The oil fields of Baku have produced ample supplies of oil, especially under the erstwhile USSR government. A famous “Contract of the Century” in 1994 led to the setup of the Baku-Tbilisi-Ceyhan pipeline that was used to transport Azeri oil to Ceyhan.

7. World-famous Caviar is farmed from the Caspian Sea

Caviar is an expensive delicacy enjoyed worldwide, and the Caspian Sea is a major site of roe farming. So how is caviar made, and how does this region produce it? It is the salt-cured roe or eggs of certain fish species, including salmon and sturgeon.

Predominantly, caviar refers solely to roe farmed from the Caspian and Black Seas, and the term encompasses different species of fish native to the region. The origins of caviar can be traced back to the 10th century when roe was farmed from the Sea of Azov in Europe.

To provide an idea of its retail value, 1 kg of albino sturgeon caviar sells for a staggering $34,500, while wild Beluga sturgeon caviar sells for upwards of $16,000 per kg. The main species of sturgeon in the Caspian Sea that are famed for their caviar are the Persian, Russian, Beluga, sterlet, starry, and bastard varieties. The beluga sturgeon is a large freshwater fish native to the Caspian.

Unfortunately, roe farming is very lucrative, leading to overfishing. Caviar farming predominantly targets the reproducing females of the sturgeon species. There have been numerous bans on fishing in the region, but the practice continues illegally.

8. The Caspian Sea is bounded by five countries and lies at the junction of 2 continents

Along the vast coastline of the Caspian Sea spanning 7,000 kilometres, five nations border it. In the North lies the countries of Russia and Kazakhstan. In the South lies Iran, South East lies Turkmenistan, and South-West lies Azerbaijan.

The longest border is with Kazakhstan at over 1400 km, followed by Turkmenistan, Azerbaijan, Russia, and lastly, Iran at 728 km. The countries of Uzbekistan, Armenia, Georgia, and Turkey lie a few hundred kilometres from the Caspian Sea.

The capital of Azerbaijan- Baku, lies on the coastline and derives much of its economy from fishing and maritime industries. The Iranian capital of Tehran is roughly 100 km south of the shore. The coastline is dotted with numerous cities, including a large number of naval forts.

Some other major cities on the coastline are as follows:

  1. Makhachkala in Russia, and the cities of Astrakhan and Grozny along rivers that feed on the Caspian Sea.
  2. Rasht and Sari in Iran.
  3. Turkmenbashi and Balkanabat in Turkmenistan.
  4. Atyrau, Aktau, Zhanaozen, and Fort-Shevchenko in Kazakhstan.
  5. Baku, Khachmaz, Sumqayit, and Astara in Azerbaijan.

The Caspian Sea lies at the junction of 2 continents- Europe and Asia, close to the Ural mountain ranges that divide both continents.

9. The Caspian Sea is in the middle of a territorial dispute by the bordering nations

As a water body rich in natural resources, there have constantly been minor territorial skirmishes between the bordering five nations. Starting in 2000, discussions have been going on regarding the demarcation of the Sea. The main points of contention were the minerals, oil and gas deposits, fishing regions, and connectivity to other water bodies.

The landlocked countries bordering the Sea are Turkmenistan, Kazakhstan, and Azerbaijan. To connect with other nations through the Black and Baltic Seas, they depend on free passage through rivers in Russia, namely the Volga. However, if free access is provided, Russia’s main trading route will suffer congestion and vessel inaccessibility to ports. This has been a major point of discussion in the ongoing summits.

The current demarcation has divided the Sea into two zones- Iran and Soviet regions. The Soviet region comprises Turkmenistan, Kazakhstan, Russia, and Azerbaijan. Despite the division, the nations equally shared non-mineral resources such as fish.

However, mineral resources, including oil and gas reserves, had to be demarcated to prevent tensions over excess mining. The main conflicts are between Iran, Azerbaijan, and Turkmenistan. Azerbaijani research vessels claim to have come under fire from both parties during routine expeditions.

Iran has repeatedly claimed illegal incursions, while Turkmenistan alleges Azerbaijan has pumped more than the agreed share of oil from a standard subsea deposit. For this reason, all five nations have naval fleets active in the region to safeguard their national interests.

Iran has proposed the solution of an equal 1/5th share to each nation, but it has been largely rejected since Iran has the smallest coastline but will receive an unduly large percentage of the resources.

10. Legally, the Caspian Sea is neither a sea nor a lake

Most water bodies today have been classified into broad groups- oceans, seas, lakes, rivers, streams, and pools (further classified into above the ground, underground, etc.). However, the Caspian Sea is unique as it has never been successfully organised. Even as recent as 2018, an inter-governmental effort to determine its status yielded no results.

So why the confusion? A lake is a body of water that does not feed into an ocean and is generally landlocked on most of its boundaries. The Caspian Sea fits that description since it is not connected to any ocean (the nearest being several hundreds of kilometres away) and is predominantly landlocked, barring a few rivers flowing into it.

At the same time, a sea is a large body of water in surface area and depth, but not as big as an ocean. And the Caspian Sea suits these descriptors as well since it is a vast body of water covering 371,000 square kilometres with an average depth of 211 meters and a maximum depth of over 1 kilometre.

So, what is the implication of not being categorized as a sea or a lake? Well, it is called a lake, the world’s largest lake.

In the previous section, we outlined how the landlocked countries of Azerbaijan, Turkmenistan, and Kazakhstan are dependent on free passage through the Volga for trade to other countries.

By legal precedent, a Sea cannot be claimed by any single nation, and any country’s fleet is free to use it within limitations set by the UN or IMO. However, a lake can be claimed by a single or group of nations, and passage is not necessarily available to all. This led to a territorial dispute since the Caspian hasn’t been demarcated, making it a unique case.

Furthermore, the exact division of resources has come under scrutiny, given that some nations have a longer coastline on the Sea than others. While there seems to be no end to this dilemma, the discussions have been largely peaceful, with a plan to achieve a solution within the next few years.

Frequently Asked Questions

1. What is the Caspian Sea famous for?

It is home to a wide range of plant and animal species and is known for the profitable caviar and oil industries. It has herring, sturgeon, sharks, sprat, perch, pike, molluscs and sponges.

2. Is the Caspian Sea dead sea?

Cancer rates in regions bordering the sea are higher than the average in the countries bordering it. During the Soviet Period, coastal cities like Baku and Sumgayit were heavily industrialized, so today, the sea around these cities is a dead ecological zone.

3. Can you swim in the Caspian Sea?

Most parts of the sea are perfect for swimming and relaxing. It has a fantastic climate, and not to forget that the sands in the Absheron peninsula, near Baku and other villages, are rich in minerals and salts with healing properties.

4. Can ships get out of the Caspian Sea?

It is a closed body of water; however, several canals and the Volga and Don rivers link it to the Azov Sea, allowing the movement of ships in and out of the sea.

5. Is the Caspian Sea water salty?

It has varying levels of salinity. It is about one-third as salty as the ocean. The waters are saltiest in the south and freshest in the north. It is fed by around 130 drives which flow from the north or the west.

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Disclaimer: The author’s views expressed in this article do not necessarily reflect the views of Marine Insight. Data and charts, if used, in the article have been sourced from available information and have not been authenticated by any statutory authority. The author and Marine Insight do not claim it to be accurate nor accept any responsibility for the same. The views constitute only the opinions and do not constitute any guidelines or recommendations on any course of action to be followed by the reader.

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About Author

Ajay Menon is a graduate of the Indian Institute of Technology, Kharagpur, with an integrated major in Ocean Engineering and Naval Architecture. Besides writing, he balances chess and works out tunes on his keyboard during his free time.

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