Background: The Pacific Ocean is the largest of the world's five oceans (followed by the Atlantic Ocean Indian Ocean Southern Ocean and Arctic Ocean). Strategically important access waterways include the La Perouse Tsugaru Tsushima Taiwan Singapore and Torres Straits.

Coastline: 135,663 km

Climate: the western Pacific is monsoonal - a rainy season occurs during the summer months, when moisture-laden winds blow from the ocean over the land, and a dry season during the winter months, when dry winds blow from the Asian land mass back to the ocean

Terrain: surface in the northern Pacific dominated by a clockwise, warm water gyre (broad, circular system of currents) and in the southern Pacific by a counterclockwise, cool water gyre; sea ice occurs in the Bering Sea and Sea of Okhotsk during winter and reaches maximum northern extent from Antarctica in October; the ocean floor in the eastern Pacific is dominated by the East Pacific Rise, while the western Pacific is dissected by deep trenches; the world's greatest depth is 10,924 meters in the Marianas Trench

Natural resources: oil and gas fields, polymetallic nodules, sand and gravel aggregates, placer deposits, fish

Geography
Note: the major choke points are the Bering Strait, Panama Canal, Luzon Strait, and the Singapore Strait; the Equator divides the Pacific Ocean into the North Pacific Ocean and the South Pacific Ocean; ships subject to superstructure icing in extreme north from October to May and in extreme south from May to October; persistent fog in the northern Pacific from June to December is a hazard to shipping; surrounded by a zone of violent volcanic and earthquake activity sometimes referred to as the Pacific Ring of Fire

Environment
Current issues: endangered marine species include the dugong, sea lion, sea otter, seals, turtles, and whales; oil pollution in Philippine Sea and South China Sea; dotted with low coral islands and rugged volcanic islands in the southwestern Pacific Ocean; subject to tropical cyclones (typhoons) in southeast and east Asia from May to December (most frequent from July to October; tropical cyclones (hurricanes) may form south of Mexico and strike Central America and Mexico from June to October (most common in August and September; southern shipping lanes subject to icebergs from Antarctica; occasional El Nino phenomenon occurs off the coast of Peru when the trade winds slacken and the warm Equatorial Countercurrent moves south, which kills the plankton that is the primary food source for anchovies; consequently, the anchovies move to better feeding grounds, causing resident marine birds to starve by the thousands because of their lost food source

Economy overview: The Pacific Ocean is a major contributor to the world economy and particularly to those nations its waters directly touch. It provides cheap sea transportation between East and West, extensive fishing grounds, offshore oil and gas fields, minerals, and sand and gravel for the construction industry. In 1985 over half (54%) of the world's total fish catch came from the Pacific Ocean, which is the only ocean where the fish catch has increased every year since 1978. Exploitation of offshore oil and gas reserves is playing an ever increasing role in the energy supplies of Australia, New Zealand, China, US, and Peru. The high cost of recovering offshore oil and gas, combined with the lower world prices for oil since 1985, has slowed but not stopped new drillings.

Industries: fishing, oil and gas production