Hidden beneath the waves, submarine canyons are deep, dramatic chasms in New Zealand's underwater landscape, sometimes plunging to depths of several kilometres.
But more needs to be done to protect these rich marine ecosystems from the myriad pressures humans are heaping on them, from fishing and litter to the extraction of oil and gas, scientists say in a new study.
Around the world, there are an estimated 10,000 of these major features of continental margins, with at least 230 found off the coast of New Zealand.
These include the 60km-long, 1.2km-deep Kaikoura Canyon, home to an abundance of life spanning from tiny plankton to the giant sperm whales they famously attract to the coast, and the Cook Strait Canyon, starting just 10km off the Wellington coast and reaching depths of 3km south of Cape Palliser.
Recent studies of canyons have boosted scientists' understanding of their ecological role, the benefits they bring to humans, and how our activities are affecting their environments.
Dr Ashley Rowden, a marine ecologist at the National Institute of Water and Atmosphere (Niwa), is part of an international team of scientists that has reviewed recent studies of submarine canyons around the world.
In a study published today in the scientific journal Frontiers in Marine Science, Rowden and his colleagues report how only 10 per cent of canyons worldwide are covered by marine protected areas (MPAs) - and these are not evenly distributed around the globe.