Fisheries and Their 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.