Overpopulation of shipping vessels

The Golden Horn, an arm of the Bosporus that runs beneath the walls of Istanbul, has been used as a waste site for over 2,000 years. Istanbul's population of nearly 10 million (which increases by one person per minute) and the barrage of ships that dock there dump their sewage into the Golden Horn at rate by which scientists speculate will soon make the river toxic enough to erode the metal bottoms of ships. As the Golden Horn flows into the Bosporus, which divides Europe from Asia, it increases the Bosporus' already serious ecological problems due to sea traffic congestion. One day in 1992, a Russian ship transporting 20,000 sheep collided with another freighter and sank near the coast of Istanbul. Some of the sheep were brought to shore, but the rest were left in the sea to rot. The Black Sea, fed by the Danube, the Dnieper, the Dniestr and the Don rivers, also feeds the Bosporus. Because of unsustainable commercial fishing and sea traffic in the Black Sea, only 6 of the 26 species of commercial fish landed in the 1960's were worth catching in 1992. 95% of the main species of seaweed on the north-western shelf of the Black Sea has been obliterated. The Danube River, accounting for more than half of the river flow into the Black Sea, was estimated in 1992 to carry 50,000 tons of oil into the Black Sea each year.