Diving the Poor Knights Islands

The islands are of volcanic origin, created by a series of eruptions some ten million years ago, and subsequently eroded to their present form. The islands have been ecologically separated from the mainland for about two million years, and are a haven for some of the most endangered terrestrial native wildlife. The Poor Knights comprises two larger islands, Tawhiti Rahi to the north, and Aorangi to the south, and a scattering of islets and rocks, the largest of which are Aorangaia and Archway island, to the south east of Aorangi. A group of smaller islets to the south west is called the Pinnacles, and the southernmost of these is the Sugarloaf.

From S35°26.646' to S35°29.518', and from E174°43.896' to E174°44.913', roughly 20km from the mainland

• Tawhiti Rahi is about 2.9 km from north to south, and generally less than a kilometer wide.
• Aorangi is about 1.7km north to south and also generally less than a kilometer wide.
• Aorangaia and Archway Island are each about 350m long and about 150m wide.
• High Peak Rock (the Pinnacles) is at S35°32.840', E174°43.516'
• Sugarloaf Rock is at S35&deg33.993', E174°42.402'

Some sites are subject to strong currents, particularly at spring tides. These areas are mostly at archways, headlands and narrow gaps, and the currents may be too strong to swim against.

Water temperatures are moderate, ranging between 14°C in winter and 22°C in summer.

Visibility is generally between 15m and 40m for much of the year, and is usually best from late summer to the end of winter, during which time there is less plankton in the water. From September to November plankton blooms may reduce visibility to between 5 and 10 m.

The marine ecology is diverse, and the abundance of steep walls, overhangs, arches and caves provide relatively shallow shaded environments suited to organisms that would otherwise be found considerably deeper.

There is a noticeable seasonal variation in the ecology, due at least partly to changes in temperature and lighting. The warming of the water and increased light in spring trigger plankton blooms, which provide food for the ecosystem and this triggers spawning and growth in many species.

Large aggregations of stingrays occur during summer, and visits from tropical pelagic species like mantas and sunfish become common.

The Poor Knights region is representative of the temperate location of North Island, but also supports tropical visitors, which find a home among the unfamiliar kelp forests. The islands are close to the edge of the continental shelf where there are upwellings of nutrient rich water, which provides a fairly constant supply of food to the extensive diversity of filter feeders. Density of organisms is generally greatest in places where the water flow is strongest, and benthic animals are most prevalent where the light levels are too low for lush growth of seaweeds, such as under the arches and along the walls.

The East Auckland current originates in the tropical waters off the east coast of Australia, and carries larval stages of tropical animals past Northland's east coast, where some of them settle on the reefs of the Poor Knights. Many of them do not survive the winter, but a few relatively hardy ones manage to make it through a few years. The waters are too cold for tropical reef-building corals, but provide ideal conditions for a range of seaweeds, which provide food and habitat for a variety of invertebrates and fish.

About 120 species of fish are known from this region, and many of them occur in large numbers.

Ordinary recreational scuba equipment is adequate for most dives in this region. A 5 mm wetsuit is sufficient in summer, but 7 mm wetsuit or drysuit is recommended in winter. Appropriate technical equipment and training is recommended for the deeper dives.

• Wild Beast Point

Position: — S35°26.636', E174°44.212'

• Cream Gardens

Position: — S35°26.895', E174°44.483'

• Splendid Arch
• Barren Arch

Position: — S35°27.365', E174°44.477'

• Cave Bay
• Dark Forest
• Hope Point

Position: — S35°27.655', E174°44.720'

• Airbubble Caves
• Rock Lily Inlet

• Maomao Arch:

Position: — S35°28.049', E174°44.305'

• Butterfish Bay
• Taravana Caves

Position: — S35°27.941', E174°44.187'

• Landing Bay Pinnacle

Position: — S35°27.884', E174°44.156'

• Phil's Knob

Position: — S35°27.904', E174°44.060'

• Giant Staircase
• Middle Arch

Position: — S35°27.441', E174°43.993'

• Cleaner Fish Bay
• Northern Arch

Position: — S35°26.872', E174°43.911'

• Ann's Rock

• Bartles Bay
• Seal Rock
• Long Cave
• Mine Shaft Cave
• Fred's Pinnacle
• Fraser's Landing

• Jan's Tunnel: S35°29.269', E174°44.196'
• Oculina Point:
• Crystal Cave:
• Red Baron Caves: S35°28.962', E174°43.967'
• Kahawai Point:
• Rikoriko Cave: S35°28.886', E174°097'
• Gentle Forest:
• Meditation Wall:
• The Gardens:
• Trevor's Rocks:
• Mary's Wall:
• The Labyrinth:
• Nursery Cove:
• Sand Gardens:

• Bird Rock
• Rogers Rocks
• Rock Gardens
• Serpent Rock
• Dutch Cove
• Middle Channel
• The Canyons

• The Tunnel
• Shaft Cave
• Labrid Channel

Position: — S35°29.252', E174°44.387'

• Blue Maomao Arch

Position: — S35°29.308', E174°44.379'

• The Rock
• Southern Arch
• Imagination Point

Position: &mdash ;S35°29.520', E174°44.373'

• Crinoid Cliff
• Ngoio Reef/Rock

Position: — S35°29.375', E174°44.300'

• Magic Wall

• Inside the sea cave on the east side of Aorangaia
• Salps may be present in large numbers at some times of the year
• The Red Moki is a widespread and fairly common fish

• The Slot

Position: — S35°32.770', E174°43.480'

• Cathedral Cave:
• Tie Dye Arch

Position: — S35°32.889', E174°43.486'

• Scary Deep:
• Sunken Rock:
• Sugarloaf

Position: — S35°33.983', E174°42.336'