Fisheries and Their Ecosystems

Incredible marine habitats and ecosystems.

Incredible marine habitats and ecosystems

New Zealand's 200 nautical miles Exclusive Economic Zone (EEZ) covers around 4.4 million square kilometres, and is the fourth largest in the world.

Within this lies a rich and complex seascape with a great variety of marine habitats and life forms. There are undersea plateaus and mountain ranges, volcanoes, coastal estuaries and the 10,000 - metre deep Kermadec Trench - the second deepest point on Earth.

Over 15,000 marine species have already been found living in these seas. And scientists think that another 50,000 may yet be found here. This could represent about 10 percent of the world's known marine species.

Also, our isolation in the south-west Pacific means that there are many species unique to New Zealand.

Many migratory species also visit our waters. In fact, some marine mammal and seabird species depend on New Zealand breeding areas and feeding grounds for their existence.

Oceans and productivity

The most productive areas of the world's oceans are where cold, nutrient-rich waters mix with warm surface waters. This occurs on a huge scale off Chile, Peru and Argentina. By comparison, only a small amount of New Zealand's offshore waters are highly productive.

New Zealand's ocean productivity results from a combination of its location in the Pacific, its undersea landscape, ocean currents, and climate.

Warm subtropical surface waters bathe the North Island and the west coast of the South Island. Much colder subantarctic surface waters surround the rest of the South Island and offshore islands to the south and east. These warm and cold waters meet to create the Subtropical Front, an ocean feature that circles the Southern Hemisphere.

Here, nutrient rich waters from the south mix with the warmer northern waters. These create ideal conditions for plankton and the animals that feed on them. This is good news for our fisheries. On the Chatham Rise and in the subantarctic, the undersea landscape and currents enhance these conditions.

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Updated : 16 November 2007

A network of marine protection

The government is setting up a network of Marine Protected Areas (MPAs) to protect examples of our different marine habitats and ecosystems, as well as those that are outstanding or rare. Like our land-based Protected Natural Areas network, this will make sure some of our biological wealth in the seas is "banked" as an investment for future generations.

Some areas are already protected by marine reserves, Fisheries Act closures, and cable protection zones. These have each been set up to achieve slightly different things, and so are not integrated in any structured way.

The MPA process will make sure that future marine protection is properly planned and integrated. We will decide what areas need protecting in our coastal waters (out to 12 nautical miles) on a region-by-region basis, and make decisions about protection in our EEZ at a national level.

The process is being run jointly by the Ministry of Fisheries and the Department of Conservation, and will involve other government departments, local government, marine users, tangata whenua, and groups with an interest in the marine environment.