Hawea (Clio Rocks)

Hawea (Clio Rocks) Marine Reserve protects 4.11 square kilometres (411 hectares) of Bligh Sound (Hāwea), one of the deep glacial fiords of Fiordland on New Zealand's South Island. ^[1] Established in 2005 under the Fiordland (Te Moana o Atawhenua) Marine Management Act, it was one of eight new marine reserves created in Fiordland that year, bringing the network there to ten reserves in total. ^[2] Centred on the submerged Clio Rocks, the reserve safeguards the steep underwater walls and sheltered waters characteristic of Bligh Sound. Like other Fiordland reserves it is managed by the Department of Conservation (DOC) in partnership with the Guardians of Fiordland's Fisheries and Marine Environment, a community body that helped design the wider marine management plan. Within its boundaries all marine life is fully protected, with no fishing or collecting permitted.

The waters of Bligh Sound support marine communities typical of Fiordland's sheltered fiords, where steep rock walls drop away into deep water. A distinctive feature of these fiords is the phenomenon known as deep-water emergence, in which species that normally live in much deeper, darker ocean conditions occur at unusually shallow depths because the tannin-stained freshwater layer at the surface limits light penetration. ^[1] Encrusting invertebrates, sponges, anemones, black corals and other filter-feeding life cover the submerged walls around the Clio Rocks. Marine mammals and seabirds that range throughout Fiordland's coast and fiords — including bottlenose dolphins, New Zealand fur seals and Fiordland crested penguins — may also be encountered in and around the sound. As a fully protected no-take reserve, the area allows these communities to develop without the pressure of fishing or harvesting.

Beneath the surface, the reserve's most notable plant-like and sessile life consists of marine algae and the dense invertebrate growth that clings to the fiord's rock walls. The unusual layering of fresh and salt water in Bligh Sound shapes which species can grow at given depths, with the dim conditions favouring shade-tolerant and deep-water organisms near the surface. ^[1] Above the waterline, the surrounding land within Fiordland National Park is cloaked in temperate rainforest of southern beech and podocarp species, with mosses, ferns and lichens thriving in the consistently high rainfall. This forested catchment feeds the tannin-rich freshwater runoff that is central to the fiord's distinctive underwater conditions.

Bligh Sound is a classic glacial fiord, carved by ice during successive glaciations that gouged deep, steep-sided troughs into the hard rock of the Fiordland massif. ^[1] When the glaciers retreated and sea levels rose, the sea flooded these valleys to create the long, narrow fiords seen today, with underwater walls plunging steeply from the shoreline. The Clio Rocks at the centre of the reserve are part of this drowned glacial landscape. The bedrock of the region is dominated by ancient, resistant crystalline rocks, including gneiss and granite, which give the fiord walls their sheer, enduring character. High annual rainfall delivers a constant flow of freshwater that floats over the denser seawater, producing the stratified water column that defines the reserve.

Fiordland has one of the wettest temperate climates in the world, and Bligh Sound shares this character with very high annual rainfall spread across the year. ^[1] Frequent rain washes tannins from the surrounding forested slopes into the fiord, creating a dark, freshwater surface layer that strongly influences the underwater environment. Temperatures are mild and oceanic, moderated by the surrounding sea, with cool wet winters and relatively cool summers. Cloud, mist and rapidly changing conditions are common, and strong winds can funnel through the steep-walled fiord. These persistent wet conditions are not incidental but fundamental to the reserve, sustaining the tannin-stained surface waters that allow deep-water species to appear at shallow depths.

Fiordland holds deep significance for Ngāi Tahu, the principal Māori iwi of the South Island, whose ancestors travelled and harvested resources along this rugged coast and its fiords over many generations. ^[1] The fiords feature in Māori tradition and place names, and the name Hāwea associated with the reserve reflects this heritage. European contact came later, with explorers, sealers and surveyors charting the Fiordland coast from the late eighteenth and nineteenth centuries; the name Clio Rocks reflects this era of European maritime naming. The remoteness and difficult terrain of the region meant that permanent settlement never took hold, leaving the fiords largely undeveloped and their marine environments comparatively undisturbed into the modern era.

The marine reserve was established in 2005 under the Fiordland (Te Moana o Atawhenua) Marine Management Act, legislation that arose from a collaborative process involving local communities, commercial and recreational fishers, conservationists and government. ^[1] The Guardians of Fiordland's Fisheries and Marine Environment played a central role in shaping the resulting management framework. Hawea (Clio Rocks) was one of eight new marine reserves created across Fiordland in that year, which together with earlier reserves brought the regional network to ten protected marine areas. ^[2] The intent was to safeguard representative examples of Fiordland's exceptional and unusual underwater ecosystems, including those of Bligh Sound, while balancing the interests of the people who use these waters.

As a marine reserve in a remote fiord, the area's principal attractions lie underwater rather than along walking trails. The Clio Rocks and the steep submerged walls of Bligh Sound are the focal point, with the near-vertical rock walls of Turn Round Point a notable feature, prized for the deep-water emergence that brings normally deep-living species, including black coral, within reach at relatively shallow depths beneath the tannin-stained surface layer. ^[1] For experienced divers reaching the sound by boat, these fiord walls offer a rare opportunity to observe communities that elsewhere exist only in the deep ocean. The dramatic scenery of the fiord itself, framed by forested mountain walls rising directly from the water, is a further draw for those who make the journey by sea.

Bligh Sound is remote and accessible almost exclusively by boat, with no road access to the reserve and no visitor facilities within it. ^[1] Most visitors arrive aboard charter vessels, dive boats or private craft operating along the Fiordland coast, often as part of longer expeditions through the fiords. There are no jetties, moorings dedicated to tourism, or services at the reserve, so visitors must be fully self-sufficient and prepared for the region's challenging weather and isolation. Within the reserve, all marine life is fully protected: fishing, anchoring damage to the seabed, and the collection of any marine organisms are prohibited. Visitors are expected to follow Department of Conservation guidance to minimise their impact on this sensitive environment.

Hawea (Clio Rocks) Marine Reserve is a strictly protected no-take area, meaning no fishing, harvesting or removal of marine life is allowed anywhere within its boundaries. ^[1] It forms part of an integrated approach to managing Fiordland's marine environment, established through the Fiordland (Te Moana o Atawhenua) Marine Management Act and overseen by the Department of Conservation alongside the Guardians of Fiordland's Fisheries and Marine Environment. The reserve protects a representative sample of Bligh Sound's distinctive ecosystems, including the deep-water-emergence communities that make Fiordland's fiords internationally significant. Ongoing conservation priorities include guarding against marine biosecurity threats such as invasive species and the marine algae that can be spread on vessel hulls, monitoring the health of protected communities, and maintaining the natural freshwater inflows that underpin the fiord's unique conditions.