The Lake Sevan (Geghama Sea) is located in the region of Gegharkunik. It is the biggest of Armenia, as well as the 3rd biggest lake in the whole Armenian plateau (after the lakes Van and Urmia). In ancient times it was known as Geghama Sea, Gegharkunyats Sea or Lokhmita. Unlike the Urmia and Van lakes, Sevan is an open lake and has sweet water. 28 rivers flow into the lake Sevan and only one river - Hrazdan begins from it. The lake Sevan earlier had 12 fish species. Nowadays there are only some of them in the lake. The endemic fish for the lake Sevan is the trout, gegharkuni, summer bakhtak, winter bakhtak and bojak. Sevan earlier had one island, which later became a peninsula, resulted by the lowering of the water level.