Peru

Abstract

The coast of Peru extends in a fairly straight line for over 3080 km. Most of the coastal zone is arid semi-desert, though the northern end has landscapes with streams and great expanses of vegetation, having notable stands of mangroves with a rich diversity. The continental shelf is up to 65 miles in the central section, but is much narrower in the southern and northern ends of the coast. Climate is influenced by the Peruvian or Humboldt Current whose cool temperature condenses moisture in the equatorial air masses, producing fog and clouds in the central coastal region. The upwelling off the Peruvian coast is exceptionally important, with marked effects on sea level, climate and on productivity. During El Nino events, the upwelling is suppressed, and the pelagic ecosystem suffers radical changes: warm waters which are poor in nutrients flow in and inhibit high primary production, and modify the composition of the plankton. The herbivorous pelagic fish which feed on the plankton are reduced as a 'tropicalization' occurs due to the migration of different species from equatorial waters. Copepods which are the dominant group during normal years and which are herbivorous, decline and are replaced by warm-water species which generally are carnivorous predators of eggs and fish larvae. Peak production of anchovy and sardine have been over 9 million tons, especially related to the first fishery resource. There has been a marked population growth since the 1950s. Habitats in the coastal zone in Peru have suffered alterations from both natural processes and various activities resulting from the increase in population and increasing demand for land. Heavy use of pesticides has produced toxic residues, although the main pollution is based on domestic and industrial residual wastes that contaminate beds of rivers, altering the quality of fresh waters and the Peruvian marine coast, but new laws and several protected areas are now encouraging environmental considerations in new development.