Chapter 36D. South Pacific Ocean

The Pacific Ocean is the Earth’s largest ocean, covering one-third of the world’s surface. This huge expanse of ocean supports the most extensive and diverse coral reefs in the world (Burke et al., 2011), the largest commercial fishery (FAO, 2014), the most and deepest oceanic trenches (General Bathymetric Chart of the Oceans, available at www.gebco.net), the largest upwelling system (Spalding et al., 2012), the healthiest and, in some cases, largest remaining populations of many globally rare and threatened species, including marine mammals, seabirds and marine reptiles (Tittensor et al., 2010).

The South Pacific Ocean surrounds and is bordered by 23 countries and territories (for the purpose of this chapter, countries west of Papua New Guinea are not considered to be part of the South Pacific), which range in size from small atolls (e.g., Nauru) to continents (South America, Australia). Associated populations of each of the countries and territories range from less than 10,000 (Tokelau, Nauru, Tuvalu) to nearly 30.5 million (Peru; Population Estimates and Projections, World Bank Group, accessed at http://data.worldbank.org/data-catalog/population-projection-tables, August 2014). Most of the tropical and sub-tropical western and central South Pacific Ocean is contained within exclusive economic zones (EEZs), whereas vast expanses of temperate waters are associated with high seas areas (Figure 1). The eastern and western extremes of the ocean basin contain two major boundary currents: the poleward-flowing East Australian Current (EAC), which runs along Australia’s North-West shelf in the west (Ridgway and Dunn, 2003) and the northward-flowing Humboldt Current, which runs along South America’s continental shelf in the east (Montecino and Lange, 2009). The dominant shallow water ecosystems of the region are tropical coral reef and lagoon systems and mangrove communities in the sub-tropics and tropics and temperate rocky reefs and kelp beds in temperate zones. Other marine communities across tropical, sub-tropical and temperate zones include rocky intertidals, mudflats, seagrass beds, estuaries and salt marshes in inshore areas and seamount, hydrothermal vents and trenches in offshore zones. Five Large Marine Ecosystems (www.lme.edc.uri.edu) have been defined across the South Pacific Ocean, including the Humboldt Current, the northeast Australian shelf, east-central Australian shelf, southeast Australian shelf and New Zealand shelf.