Black Sea (Karadeniz in Turkish) lies to the north of Turkey, bordering with two regions; Marmara and Black Sea. Besides Turkey, other countries that circle the Black Sea are; Bulgaria, Romania, Russia, Ukraine, and Georgia. It's connected to the Sea of Marmara with the Bosphorus Strait in the southwest. Some of the important ports on the Black Sea are; Istanbul, Trabzon, Samsun, Sinop, Burgas, Varna, Constanza, Yalta, Odessa, Sevastopol, Kerch, Novorossiysk, Sochi, Sukhumi, Poti, and Batumi. Black Sea is an inland sea covering an area of about 420thousand square kilometers reaching at 2206 meters in its deepest point. Below 200 meters the oxygen level in the water is very low so marine life is very limited below this depth. Most known fish they catch in the Black Sea are; Black Sea turbot, gurnard, and small sharks. Its waters are warm in the summer, very cold in the winter. Its salinity is around 0,18% because of a constant inflow of fresh water from rivers surrounding it, the excess water flows on the surface through the Bosphorus meanwhile the warm and salty waters of the Mediterranean reach the Black Sea with deep water currents, maintaining the stratification and salinity levels. The most important rivers flowing into the Black Sea are Danube from north east, Kizilirmak, Sakarya and Yesilirmak from Anatolia in the south. Black Sea is one of the youngest seas on the Earth, its used to be a big fresh water lake some 8000 years ago. The name is probably derived from the color of its deep waters.