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The Caspian Sea

Caspian Sea (ancient Caspium Mare or Hyrcanium Mare), saltwater lake in southeastern Europe and southwestern Asia is the largest inland body of water in the world. The Caspian Sea is bordered on the west by Azerbaijan and Russia, on the northeast and east by Kazakhstan, on the east by Turkmenistan, and on the south by Iran. It extends about 1210 km (about 750 mi) in a northern and southern direction and about 210 to 436 km (about 130 to 271 mi) in an eastern and western direction. It has an area of 371,000 sq km (143,000 sq mi). The Caspian coastline is irregular, with large gulfs on the east, including Krasnovodsk Gulf and the very shallow Garabogazk Gulf, which acts as an evaporation basin and is the site of a major chemical plant that extracts salts from the deposits.

The Caspian Sea has a mean depth of about 170 m (about 550 ft) and is deepest in the south. Its level varies from year to year but averages about 28 m (92 ft) below sea level. In the 1960s and 1970s the level fell substantially, partly because water was withdrawn from tributary rivers for irrigation and other purposes. In 1980, a dike was built across the mouth of Garabogazk Gulf to reduce water loss, creating a lake that was expected to last for several years. Instead, the gulf dried up completely by 1983. In the meantime, the level of the Caspian Sea began rising again at a rate of about 14 to 20 cm (about 6 to 8 in) annually. To restore water flow into Garabogazk Gulf an aqueduct was built.

The southern and southwestern shorelines of the Caspian Sea are bordered by the Elburz Mountains and the Caucasus Mountains. The sea has numerous tributaries, notably the Volga, Ural, and Zhem rivers, all of which flow into it from the north. Other tributaries include the Gorgan (Gurgan) and Atrek rivers, flowing from the east, and the Kura River, flowing from the west. The sea has no outlet. The Caspian Sea is linked to the Baltic Sea, the White Sea, and the Black Sea by an extensive network of inland waterways, chief of which is the Volga River. These waterways provide an outlet to northern Europe for the oil fields of Baku, Azerbaijan on the Abşeron Peninsula. The Caspian Sea also contains highly productive fisheries, yielding valuable catches of sturgeon (the chief source of caviar), salmon, perch, herring, and carp. Other animal life in the Caspian Sea includes tortoises, porpoises, and seals.

Navigation is frequently dangerous because of violent southeastern storms, and during the winter months the northern parts of the Caspian Sea are closed by ice. The chief ports are:

  • Krasnovodsk, Turkmenistan
  • Baku
  • Makhachkala, Russia

Habitat around Caspian Sea

The sea has also been called, the Hyrcanian, Âbaskun, Jorjân, Xorâsân, Tabarestân, Mazanderan, Xvalyn, and Xazar, the latter name is used in Persian, Azeri and Turkish languages. The most populous parts, the southern and western Caspian coasts belonged to Iran until the Arab conquest in the 7th century AD. Culturally and linguistically, they retained their Iranian character in the following centuries, but in the middle ages, the population became fused with the incoming waves of Turkic nomadic tribes, and these immigrants accounted for an increasingly large component of the ethnic make-up. Eventually, Azerbaijan became linguistically turkified, while otherwise remaining a part of Iranian world.

Marine life

The area of the Caspian Sea is about 422,000 km2 with 6397 km coastline, of which more than 900 km is along the Iranian side. About 128 large and small rivers flow into the Caspian Sea from Iran, among them the four largest rivers are: Sepidrud, Shalman, Shafarood, and Tonekâ bon. The highest salinity level reaches 12.7 ppt (about 1/3 of the ocean salinity) during summers. The average water temperature in the coastal regions throughout the year ranges from 15.9 to 17 degree Celsius. Temperature difference between the coldest area in the north and the warmest area in the south is 4 degrees during winter and 16 degrees during summer.

Commercial Species:
There are over 120 fish species in the southern part of the Caspian Sea, which are commercially divided in two groups of sturgeons and bony fishes. The bony fishes are also divided into kilka and other species. The main commercial species are as follows:


  • Beluga (Huso huso)
  • Russian sturgeon (Acipenser guldenstadti)
  • Iranian sturgeon (A. persicus)
  • Sevruga (A. stellatus)
The Iranian Caviar, being a famous and exclusive product worldwide, is produced by these species.

Kilkas (small Clupeidae):

  • Clupeonella delicatula
  • C. engrauliformis
  • C. grimmi
Other bony fishes:
  • Kutum (Rutilus frisii kutum)
  • Mullets (Mugil auratus and M. saliens)
  • Carp (Cuprinus carpio)
  • Bream (Abramis brama)
  • Pike-perch (Lucioperca lucioperca)
  • Roach (Rutilus rutilus)
  • Salmon (Salmo trutta caspius)
Sustainable Fisheries

Iranian Fisheries (Šilât) has put great emphasis on development of sustainable fisheries. Large sums of money are allocated for preservation of sturgeons. Because of their importance, fishing sturgeons, caviar-producing species, is only the responsibility of Iranian Fisheries. On the other hand, Iranian Fisheries monitors fishing methods to prevent over fishing and damage to fish stocks. For example, beach seining is the only allowed fishing system for licensed cooperatives to catch bony fishes other than kilka. In order to prevent illegal fishing, marine guards control the fishing activities in the Caspian Sea. Iranian Fisheries has established Iranian Fisheries Research and Training Organization to give technical and scientific supports for fisheries related activities. Funds are allocated to researches on identification and conservation of fish stocks. Annually millions of fingerlings are produced by Iranian Fisheries in propagation centers and released in the Caspian Sea to ensure the availability of different fish species in this water body. The fingerlings of following species are produced by Iranian Fisheries:

  • Rutilus frisii kutum,
  • Acipenseridae
  • Abramis brama.
Threats to Biodiversity
The Caspian Sea is a closed water body connected to the open sea through the Volga River. This makes it very vulnerable to the effects of industrial pollution. Oil exploration activities, by the Caspian Sea littoral Countries, have increased in the past decade. There are also international plans to transfer oil and gas through underwater pipelines in the Caspian Sea. These activities will certainly have adverse effects on marine and coastal ecosystems of Iran.

In the domestic side, development of coastal communities, pouring the sewage in the coastal waters, as well as polluted rivers threatens the coastal ecosystems. Population increase and unemployment in the region also increase illegal fishing. Man-made barriers and obstacles close the migration routes of fishes, and no fish ways are anticipated along their migration routes, therefore, many spawning grounds are destroyed.