Eastern Pacific High Sea

These open waters occupy the eastern Pacific beyond the American coast. The Pacific is divided by circulation into largely independent North and South Pacific volumes meeting at the Equator, while four quadrants (northeast and southeast off the Americas, northwest near Far Eastern Asia, southwest around Oceania) help describe its enormous extent. The American side therefore faces several climatic and marine zones rather than a single narrow coastal sea.

Temperature and salinity change markedly with latitude: surface water ranges from about -1.4°C in polar areas to nearly 30°C near the Equator, and equatorial rainfall makes those waters less saline than mid-latitude seas. Although southern and eastern trade winds are unusually steady, the North Pacific experiences more varied conditions. Hurricanes may form south of Mexico, sometimes reach the western Mexican coast, and occur mainly from June to October.

The ocean also supports fisheries, but use of shallow coastal waters varies widely rather than forming one uniform eastern Pacific economy. Its open waters are a broad transition between American shores and the central basin, where surface conditions, winds and currents vary across a scale far larger than any single coast can show.