Te Tapuwae o Hua (Long Sound)

Te Tapuwae o Hua (Long Sound) Marine Reserve protects 3,672 hectares of fiord waters in Long Sound, an arm of Preservation Inlet (Rakituma) at the remote southern end of Fiordland on New Zealand's South Island. ^[1] Established in 2005 as part of a network of ten Fiordland marine reserves, it is managed by the Department of Conservation and lies within Fiordland National Park and the Te Wahipounamu World Heritage Area. As the southernmost and largest of the Fiordland reserves, it protects deeply indented, sheltered fiord waters renowned for an especially well-developed 'deep-water emergence' effect, where a thick tannin-stained freshwater layer allows black coral and other deep-sea species to live remarkably close to the surface. Its isolation makes it one of the most pristine and least-disturbed marine areas in the country.

Long Sound's sheltered, dark waters foster some of the richest deep-emergence communities in Fiordland. Black coral, sea fans, sea pens and a wealth of filter-feeding invertebrates such as brachiopods, snake stars, hydroids and sponges thrive on the shaded rock walls at depths divers can reach. ^[1] The Narrows area hosts internationally recognised 'strawberry fields' featuring sea cucumbers and red coral, and a genetically distinct 11-armed starfish. Fish including blue cod, butterfish, trumpeter and tarakihi occupy the saltier layers beneath the freshwater surface. New Zealand fur seals haul out within Preservation Inlet, Fiordland crested penguins (tawaki) breed along the surrounding coast, and bottlenose dolphins range through the inlet.

In the upper, lower-salinity layer of the fiord, kelp and red and brown seaweeds grow on the rock together with encrusting coralline algae, while at greater depth the dark tannin-stained water blocks light and invertebrates replace plants on the walls. The deep-emergence effect in Long Sound is particularly strong, compressing these zones and bringing deep-water communities close to the surface. ^[1] Surrounding the inlet, dense temperate rainforest of southern beech, rimu, tree ferns and a profusion of mosses, ferns and epiphytes blankets the steep slopes in the very high rainfall, continually shedding tannins and organic matter that stain the runoff and sustain the fiord's distinctive layered water column.

Preservation Inlet and Long Sound are part of the glacial fiord system that defines Fiordland, carved by ice during successive glaciations into deep, branching U-shaped troughs later drowned by the sea. The surrounding mountains and the rock walls dropping into the reserve are built of hard ancient crystalline rocks, including granite and gneiss, that resist erosion and form the fiord's steep flanks and islands. ^[1] This southern part of Fiordland also has a notable history of gold-bearing geology that drew miners in the past. Below the water, the fiord's deep, steep-sided basins and rocky walls continue the glacial topography that creates the sheltered, light-limited habitats favouring deep-water marine life.

Southern Fiordland endures one of the wettest, most exposed climates in New Zealand, with very heavy rainfall on most days and frequent storms sweeping in from the Southern Ocean. The maritime, temperate climate is cool throughout the year, dominated by cloud, mist and rapidly changing conditions, with snow on surrounding peaks in winter. Mild summers and cold winters frame a landscape almost perpetually washed by rain that feeds countless waterfalls. This persistent freshwater runoff is the engine of the reserve's ecology, building and renewing the thick tannin-stained freshwater layer over the salt water that gives Long Sound its exceptionally strong deep-water emergence.

Preservation Inlet has a richer history of human activity than most Fiordland fiords. For Ngāi Tahu and earlier Māori, the southern fiords offered seasonal resources and were part of long-standing connections to the land and sea. From the late eighteenth and nineteenth centuries the inlet saw sealing and whaling, and in the 1890s gold rushes brought short-lived settlements to the wider inlet before fading away. The area's deep significance to Ngāi Tahu is now recognised within Treaty of Waitangi settlements and co-management of Fiordland. ^[1]

The Te Tapuwae o Hua (Long Sound) Marine Reserve was established on 21 April 2005 as one of eight new Fiordland marine reserves created under the Fiordland (Te Moana o Atawhenua) Marine Management Act 2005, following a collaborative process led by the Fiordland Marine Guardians with iwi, scientists, fishers and the community. ^[1] The reserve was chosen to protect the outstanding deep-emergence communities of Long Sound, regarded as among the best examples of this rare phenomenon in Fiordland. Its protection forms part of an integrated management plan balancing conservation with customary, recreational and commercial interests. The Department of Conservation administers the reserve within the wider Fiordland Marine Management Area, with the Fiordland Marine Guardians providing community-based oversight.

Extremely remote and accessible only by sea, the reserve is experienced from the water and below it. Scuba diving is the premier activity, offering experienced divers exceptional views of black coral and dense deep-emergence invertebrate communities in some of Fiordland's most pristine waters. ^[1] The long, sheltered arm of Long Sound and the wider Preservation Inlet provide outstanding boating, kayaking and wildlife viewing, with fur seals, dolphins, penguins and seabirds commonly seen. The forested shores and profound sense of wilderness add to the appeal. There are no formed visitor trails within the reserve; its attractions are the marine environment, scenery and remoteness.

There is no road access to Preservation Inlet, and the reserve has no visitor facilities; the nearest town, Te Anau, lies about 95 km away over rugged, trackless country. ^[1] Access is by boat on multi-day voyages from the southern coast or, less commonly, by air charter, almost always as part of organised diving, fishing or wilderness expeditions. Visitors must be entirely self-sufficient and prepared for severe weather and deep isolation in this far corner of Fiordland. No fees apply to the reserve itself, but charter and expedition operators charge for transport and services, and strict marine biosecurity rules apply to all vessels entering the Fiordland fiords.

As a no-take reserve, Long Sound gives full protection to its exceptional deep-emergence communities, including extensive black coral colonies that grow extremely slowly and can be centuries old. The Department of Conservation and the Fiordland Marine Guardians monitor marine life, water quality and the threat of invasive marine pests, enforcing strict biosecurity on visiting vessels to keep species such as the invasive seaweed Undaria out of the fiords. ^[1] The reserve's remoteness has helped keep it near-pristine, but sedimentation, vessel traffic and a changing climate remain concerns. Long Sound stands as a flagship of the community-supported Fiordland marine network dedicated to preserving one of the world's finest temperate fiord ecosystems.