Most of the 15 fiords of Fiordland are 200-300 m deep, usually with a pronounced shallower ‘lip' near the mouth of the fiord, indicating ‘over-deepening' by the glacial ice. The longer fiords reach back into the heart of the mountains of Fiordland National Park; the head of Hall Arm, for instance, is 40 km from the mouth of Doubtful Sound.
The marine environment of Fiordland is quite different from the rest of New Zealand. The deeply indented coastline has given rise to two contrasting marine environments:
(a) the wild, exposed outer coastline, with typical west coast New Zealand marine community and zonation patterns, and the preferred breeding habitat for fur seals and a wide range of ocean birds such as petrels, prions, shearwaters and penguins; and
(b) the sheltered, steep-walled fiords, which have a total shoreline length of nearly 1000 km, depths up to 420 m, and a unique inversion of usual patterns of coastal marine life.
Satements of authenticity and/or integrity
The fiords are an integral part of the Fiordland landscape and ecosystems, which were included until the early 1960s within Fiordland National Park. However they were not included in the site when Fiordland National Park was listed as natural World Heritage in 1986. When the World Heritage Committee listed the park as World Heritage, one of its recommendations to the New Zealand government was "...to note the importance of the waters of the fiords as an integral part of the area and welcome any initiatives to bring them under the control of the park authorities".
In 1990, when Fiordland National Park was incorporated into the much larger (2.6 million ha) Te Wahipounamu (South-West New Zealand) World Heritage Area, the issue of listing the seabed and waters of the fiords was again raised by the IUCN (The World Conservation Union) to enhance the integrity of this outstanding World Heritage site.
In April 2005, after the passing of the Fiordland Marine Management Act, the Fiordland (Te Moana o Atawhenua) Marine Area and management regime was enacted:
- recognizing the importance of the Fiordland marine environment,
- establishing a Fiordland Marine Guardians Advisory Committee, and
- creating eight new marine reserves in addition to the existing ones of Milford Sound/Piopiotahi and Te Awaatu Channel (The Gut). These are, from north to south: Te Hapua (Sutherland Sound); Hawea (Clio Rocks) in Bligh Sound; Kahukura (Gold Arm) of Charles Sound; Kutu Parera (Gear Arm) of Bradshaw Sound; Taipari Roa (Elizabeth Island) in Malaspina Reach of Doubtful Sound; Moana Uta of Wet Jacket Arm; Taumoana in Dusky Sound (between Five Fingers Peninsula and Resolution Island); and Te Tapuwai o Hua in Long Sound of Preservation Inlet.
With these legal protection measures now adopted, the seabed and waters of the fiords have been placed on the New Zealand tentative World Heritage list, as an addition to Te Wahipounamu (South-West New Zealand) World Heritage Area.