Major Seas of the World: Map Facts and PYQ Practice

A sea is a body of saline water smaller than an ocean, usually partly enclosed by land and joined to an ocean by one or more straits. The distinction matters in the examination hall, because several famous water bodies that carry the name sea are in fact lakes with no outlet to the ocean, the Caspian, the Aral and the Dead Sea among them. A gulf or a bay is an indentation of the coast, which is why the Bay of Bengal, the largest bay in the world, is not counted among the seas. Questions on this chapter are almost always factual: which sea is the largest, which strait joins which two water bodies, which countries touch a named sea, and which sea is the saltiest or the least salty.

The largest seas of the world

The Philippine Sea, a marginal sea of the western Pacific bounded by the Philippines, Taiwan, Japan and the Mariana Islands, is the largest sea on earth, and the Mariana Trench lies along its eastern edge. The Coral Sea, off north-eastern Australia and the home of the Great Barrier Reef, comes next, followed by the Arabian Sea and the South China Sea. The Weddell Sea of Antarctica, the Caribbean Sea, the Mediterranean Sea, the Tasman Sea between Australia and New Zealand, and the Bering Sea between Russia and Alaska complete the list of the giants.

The Mediterranean and its approaches

The Mediterranean is the classic enclosed sea, with Europe to the north, Africa to the south and Asia to the east. It opens to the Atlantic through the narrow Strait of Gibraltar, to the Red Sea through the Suez Canal, which was opened in 1869, and to the Black Sea through the Dardanelles, the Sea of Marmara and the Bosphorus in turn; the Sea of Marmara is the only sea lying wholly within the territory of a single country, Turkey. Its own arms carry separate names, the Tyrrhenian, the Adriatic, the Ionian, the Aegean and the Ligurian. Beyond the Bosphorus, the Black Sea is bordered by Turkey, Bulgaria, Romania, Ukraine, Russia and Georgia, and its deep water is almost without oxygen, which makes it the largest such basin in the world. The Sea of Azov, joined to the Black Sea by the Kerch Strait, is the shallowest sea on earth, nowhere much more than a dozen metres deep.

The Red Sea and the Indian Ocean margins

The Red Sea lies in the rift between the African and the Arabian plates, which is why its shores are young and nearly straight. It joins the Gulf of Aden through the Bab-el-Mandeb strait in the south and the Mediterranean through the Suez Canal in the north, and it ends in two arms, the Gulf of Suez and the Gulf of Aqaba. No permanent river drains into it, evaporation is heavy, and it is therefore the saltiest of the open seas as well as one of the warmest, with famous coral reefs. The Arabian Sea receives the Indus, the Narmada and the Tapi; from it open the Gulf of Oman, which leads through the Strait of Hormuz into the Persian Gulf, and the Gulf of Aden. The Andaman Sea lies east of the Andaman and Nicobar Islands, and the Strait of Malacca joins it to the South China Sea.

Seas that are really lakes

Three famous water bodies have no connection with any ocean. The Caspian Sea, shared by Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan, is the largest inland water body in the world and is fed mainly by the Volga. The Aral Sea, between Kazakhstan and Uzbekistan, shrank drastically during the twentieth century when the Amu Darya and the Syr Darya were diverted to irrigate cotton, and it is the standard example of a man-made ecological disaster. The Dead Sea, between Israel and Jordan, receives the Jordan river and has no outlet, so salts have accumulated until the water is several times as salty as the ocean; its shore is the lowest exposed land surface on earth, more than four hundred metres below sea level.

The other oceans and their seas

In the Atlantic, the Sargasso Sea is unique in having no coast at all: it is bounded by the four currents of the North Atlantic gyre and takes its name from the floating Sargassum weed in which eels breed. The North Sea, between Britain and Scandinavia, is known for the Dogger Bank fishing ground and for oil and gas, and reaches the Atlantic through the Strait of Dover and the English Channel. The Baltic Sea, with its Gulfs of Bothnia, Finland and Riga, receives heavy river inflow and exchanges little water with the ocean, so it is the least saline sea in the world. In the Pacific, the Yellow Sea takes its name and its colour from the loess silt carried down by the Huang He. In the Arctic lie the Barents, Kara, Laptev, East Siberian, Chukchi and Beaufort seas, and around Antarctica the Weddell, Ross, Amundsen and Bellingshausen seas.

Straits that join the seas

Two more names are worth fixing in memory. The Mozambique Channel, between Madagascar and the African mainland, is the longest channel in the world, and the Drake Passage, between South America and Antarctica, is the roughest stretch of water crossed by shipping.