The real impacts of climate change on New Zealand's waters - and the marine life that calls them home - are being laid out by the National Institute of Water and Atmospheric Research (NIWA) in a world-first climate change atlas.
The atlas will eventually collate and simplify climate change information in New Zealand's exclusive economic zone - which stretches 200 nautical miles offshore - into an interactive web-based tool.
Users will be able to view of multiple layers of information on a digital map, with information based on different time periods - so they know how the environment is set to change in future.
NIWA expects surface waters to warm by up to four degrees Celsius in the next century and become less salty and less dense, which will reduce the rise of plant nutrients to the surface from deeper waters.
The surface layer will thin and phytoplankton - which form the basis of the ocean's food chain - will receive more light.
Increasing carbon dioxide in the atmosphere will enter the ocean, making it more acidic and meaning shells dissolve at shallower depths, while large-scale changes in wind fields will affect ocean currents.
Dr Philip Boyd, from the NIWA centre of chemical and physical oceanography, says the effects will differ between bodies of water, but fish stocks and the fisheries industry could be affected.
He says there may be areas where some marine life becomes increasingly vulnerable, and harvesting may only be able to take place in certain areas in future.
NIWA is hopeful the atlas will help inform policy decisions over the future of marine life off New Zealand's coasts.
NZN