In the 19th century, commercial shipping passing through the equatorial eastern Pacific off of Peru noted that every year there was an upwelling of plankton-rich cold water from the depths. These nutrient-rich waters attracted huge schools of fish, which turned the area into one of the world's largest fishing grounds. Occasionally, however, a warmer current would predominate, forcing the upwelling back below the surface.
局部發燙十九世紀海洋商船往來，就注意到赤道東太平洋南岸秘魯外海，每年會有湧升流經過，將海底浮游生物帶上水面，吸引大批魚群，成為世界最大漁場之一。