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.
The Subtropical Front is created by nutrient rich subantarctic waters mixing with warmer surface waters. This creates ideal conditions for plankton and the animals that feed on them.