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New Zealand’s marine environment

New Zealand has a very large marine area compared with our land size

New Zealand comprises two main islands and more than 700 smaller islands and islets. It has one of longest coastlines and one of the largest marine areas in the world, compared with its land area.

New Zealand’s territorial sea is the area extending from the coast to the 12 nautical mile limit. However, we have rights and responsibilities for a much larger marine area, extending from 12 to 200 nautical miles from the coast, referred to as the exclusive economic zone (EEZ). This includes the marine area offshore from our larger remote islands: Chatham Islands, subtropical Raoul Island, and subantarctic Campbell Island and Auckland Islands.

New Zealand has some limited rights to the extended continental shelf – the underwater land mass on which New Zealand’s main land mass and small islands sit (see figure 1). New Zealand’s marine area is between 15 and 21 times larger than our land area, depending on whether we measure to the outer limit of the EEZ or the extended continental shelf.

Our marine environment is complex and diverse

New Zealand’s continental shelf has large, shallow underwater shelf areas to the north-west (Challenger Plateau and Lord Howe Rise), and to the south-east (Chatham Rise and Campbell Plateau) (see figure 1).

Our main islands also lie on the boundary between two tectonic plates – huge moving segments of Earth’s crust – and in the pathway of warm subtropical and cooler, subantarctic surface water masses flowing from the west. The meeting point of these warm and cold water masses, known as the Subtropical Front, creates ideal conditions for plankton and the fish species that feed on them. The Subtropical Front flows from the west around the southern waters off the far south of the South Island, up the lower west coast, and out across the Chatham Rise – one of the most productive areas for fishing in New Zealand’s EEZ.

This complex geology and mix of sea temperatures and ocean currents mean our marine area has many diverse marine habitats, from saltmarsh and mangrove forests, to rocky coastal reefs, to deep sea trenches, canyons, undersea volcanoes, and seamounts.

Figure 1

Click to enlarge view

Note: EEZ – exclusive economic zone; NM – nautical miles. The small triangles within the larger EEZ border are international waters outside the EEZ.

This map illustrates the extent of New Zealand’s marine environment, outlining the boundaries of New Zealand’s territorial sea, exclusive economic zone, and extended continental shelf.

Our marine environment contributes $4 billion to the economy

In the year ended March 2013, the marine economy contributed $4.0 billion to New Zealand’s economy (1.9 percent of total gross domestic product) and provided over 102,000 filled jobs (Statistics NZ, 2016a).

Offshore minerals (primarily oil and gas) were the largest contributor to the marine economy at 48 percent, followed by shipping (24 percent), and fisheries and aquaculture (22 percent) (Statistics NZ, 2016a).

These industries can also put pressure on the marine environment, the environmental costs of which have not been quantified.

For more detail see Environmental indicators Te taiao Aotearoa: Marine economy.