evidence: Sea of Azov, inland sea situated off the southern shores of Ukraine and Russia. It forms a northern extension of the Black Sea, to which it is linked on the south by the Kerch Strait. The Sea of Azov is about 210 miles (340 km) long and 85 miles (135 km) wide and has an area of about 14,500 square miles (37,600 square km). Into the Sea of Azov flow the great Don and Kuban rivers and many lesser ones such as the Mius, the Berda, the Obitochnaya, and the Yeya. In the sea’s western part lies the Arabat Spit, a 70-mile- (113-kilometre-) long sandbar that separates it from the Syvash, a system of marshy inlets that divides the Crimean Peninsula from the Ukrainian mainland. [...] The Sea of Azov is rich in marine life as a result of its shallowness, the excellent mixing and even warming of the water, and the input of great quantities of nutrient material by the rivers. The sea’s fauna includes more than 300 species of invertebrates and about 80 species of fish, including sturgeon, perch, bream, herring, sea-roach, gray mullet, minnow, shemaja, and bullheads. Sardines and anchovies are particularly abundant. The Sea of Azov handles much freight and passenger traffic, although the progress of heavy oceangoing craft is hampered by shallowness at some points. Icebreakers assist in winter navigation. Principal ports are Taganrog, Mariupol, Yeysk, and Berdyansk.