Activities in Tuhua (Mayor Island) Marine Reserve
Activities
Diving & snorkelling
The variety of marine environments in the reserve provide a range of opportunities for snorkelling and diving.
Species and ecosystems
A "mixed weed" zone occurs from low tide mark to depths of 6-9 metres. Rock girdles are the most common seaweeds, but a variety of other brown, red and green species also characterises the zone.
Scattered amongst these weeds and beyond the depth limits of the zone there are often dense concentrations of sea urchins or kina. These graze on seaweeds and so reduce some areas to the appearance of bare rock.
From about 3-30 metres, paddleweed kelp forms dense forests wherever rock bottoms are present. Beneath these canopies there may be other smaller algal species in addition to "bushy" or "encrusting" animals such as hydroids, bryozoans, sponges, ascidians, soft corals and anemones. In depths of 30 meters or more or in areas where light levels are insufficient to support algal growth, these and other filter feeding animals are common and become more so with greater depth. Cup corals, extensive areas of lace coral and beds of black coral also occur in these deeper areas of water off this end of the island.
Other subtidal animals include large black spiny sea urchins, chitons, snails and limpets, feather stars, brittle stars, starfish and sea cucumbers, and rock lobsters and crabs.
Over 60 species of fish are known from the area. Common species in shallow, rocky areas include black angelfish, leatherjackets, hiwihiwi, marblefish, paketi, banded wrasse and red moki. Two spot demoiselles, sweep and blue maomao occur widely and red mullet or goatfish are common in sandy areas. Moray eels and stingrays are seen in parts and schools of koheru, kingfish, trevally and pink maomao often congregate near pinnacles and deeper water drop-offs. "Subtropical" species sometimes seen include Lord Howe coralfish, long-finned boarfish, clown toado and crimson cleanerfish. Fish numbers are relatively impoverished at present but are expected to increase substantially with time.
Exploring the western end
At the western end of the marine reserve a jagged reef with angular boulders slopes off steeply to the northwest from Tumutu Point. To the east of this within Opoupoto Bay, a sandy bottom with projecting boulders extends from a shoreline formed of vertical, column-like lavas which give rise to the other name of Cathedral Bay.
A series of large 3-4 metre angular rock blocks separated by gaps and crevices 1-4 metres wide and 2-3 metres deep is present in water of shallow to moderate depth (20 metres) from the area of Whakataratara Island (Maori Chief) east to and beyond Motuneke Rocks. There are almost continuous canopies of kelp forest over these shaded and sheltered crevices. The forests support many, often colourful, organisms which more usually occur in deeper water.
Exploring Orongatea Bay
Within Orongatea Bay a quite different habitat appears in the form of rounded boulders and cobbles with a diverse range of seaweeds An extensive shallow water rock platform suitable for snorkelling occurs here and bubbles emitted from a series of underwater hot springs can be seen close to shore.
Offshore from Orongatea Bay, between Tokopapa (Flat Top) Island and Tawakewake (Queen) Island, the bottom drops to 30 metres or more, and large irregular rock platform with patches of rounded boulders and sand extends to the Northeast Arising on the edge of this platform to a depth of about four metres and dropping steeply on its northern side to a sandy bench at 50 metres, is an outcrop known as the Two Fathom Reef. The steep drop-off here, which lies close to the edge of the continental shelf, illustrates well the depth related patterns of plant and animal distributions. Schools of pelagic fish species can also often be seen. Diving in this area should only be attempted by suitably experienced and qualified divers, as there are often strong currents and eddies.
Exploring the eastern end
At the eastern end of the reserve is a sheltered embayment known as Turanganui or Elephant Bay. The bay is flanked by steep borders of jagged reef, while the beach and shallows are formed of boulders giving way to coarse sand in the centre of the bay at about 15 metres deep.
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