THE BIODIVERSITY OF (NON-STURGEON) FISH IN THE CASPIAN SEA

Ichthyofauna diversity The ichthyofauna of the Caspian is not as diverse as that of seas connected with the World Ocean. There are only 76 species and subspecies (or 126 if the riverine species are included). By comparison, there are 180 species in the Black Sea and more then 500 in the Mediterranean Sea. However four genera of native Caspian fish, including 31 species and 45 subspecies are endemic, while 8 species (chum salmon, grass carp, silver carp, bighead, mosquito fish, european eel, golden and grey mullet) are relatively recent introductions. The Caspian ichthyofauna may be classified into four groups according to whether or not they are endemic and their type of endemism: 1. Widely distributed, non-endemic species- sturgeons, many carp species, perches and gobies of the genera Proterorhinus and Knipowitchia, 2. Geographical subspecies of widely distributed species outside the Caspian – trout, inconnu, roach, kutum, asp, chramula, barbel, vimba, pipe-fish and gobies, of the genera Neogobius, Mesogobius and Benthophilus, 3. Species endemic to rivers entering the Caspian – spiny loaches, bleaks, Terek barbel an