Caspian Sea
The sea has a surface area of 371,000 km (143,200 sq mi) (not including the detached lagoon of Garabogazköl) and a volume of 78,200 km(18,800 cu mi). It has a salinity of approximately 1.2% (12 g/l), about a third of the salinity of most seawater.
Archipelago Sea
In contrast to the terrestrial and coastal ecosystems of the islands, the sea itself has a relatively low biodiversity. The reason for this is the brackish nature of the water. The salinity is only 0.6% in the Archipelago. The salinity has also varied greatly during the past, making it difficult for species to adapt. However, the great number of individuals indicates a favourable environment. Typical fish species are the Baltic herring, pike, white-fish, perch and flounder.