Eastern Pacific High Sea

The eastern Pacific off Ishma belongs to the Humboldt, or Peru, Current: a cold, low-salinity eastern boundary current that runs north along western South America and reaches roughly 500 to 1,000 kilometres offshore. It spans from southern Chile to northern Peru, where its cold upwelled water meets warmer tropical water at the Equatorial Front. Strong upwelling carries nutrients to the surface and feeds phytoplankton, the base of an exceptionally productive food web. Sardines, anchovy and jack mackerel are prominent pelagic fish; eared seals, cetaceans and seabirds also depend on the system. The current's cooling effect helps keep Pacific marine air from forming rain over Peru and Chile, although clouds and fog remain frequent.

In this setting, the coast can look barren while its offshore waters are among the most productive in the world. The Humboldt ecosystem supplies roughly 18 to 20 percent of global marine fish catch and supports products ranging from fish and squid to marine mammals and birds. Its productivity is not constant: El Nino-Southern Oscillation events can disrupt upwelling, shift sardine and anchovy populations, and affect fisheries and coastal communities. These patterns link the climate of the dry shore with navigation, fishing and the movement of life through a narrow, nutrient-rich eastern Pacific corridor.