Poor Knights marine reserve
diving the mid-northern quarter
by Dr J Floor Anthoni (2007)
Begin your study of the sea at the Seafriends home page or our sitemap. Find more about the Poor Knights.
Note! for best printed results, read tips for printing. For corrections and suggestions, e-mail the author.
-- Seafriends home -- index to marine reserves in NZ -- Poor Knights index --

Mid-northern quarter of the Poor Knights Islands
Mid-northern quarter of the Poor Knights Islands.
Note that the first three depth contours are for 10, 20 and 30m depth.

Boarfish Reef
A staircase reef extends from the promontory westward, ending in a wide reef top at 22m, named Boarfish Reef (35º27.869S 174º44.022W). It is a wide barren pinnacle, dominated by large purple urchins and sponges (mainly Polymastia spp). From here the reef descends rapidly to undivable depths, through a zone of stalked kelp. One can anchor safely on the top of the hard and barren rock, as there are no boulders to snatch the anchor. Following the reef into the shallows, one can surface again at the main island. Around the reef one encounters the normal reef fish and semi-pelagics like pink maomao, demoiselles and koheru.

Sombre Forest
As its name suggests, Sombre Forest is usually in the dark because of high cliffs to the east and north blocking direct sunlight. Under water the cliffs extend into a monotonous kelp forest. It is also sheltered from storms, reason why a good dive can still be had, exploring the walls at shallow depths. For photographers there are good opportunities to photograph cathedral light in the morning hours.


The Giant Staircase and Landing Bay Pinnacle
The giant staircase is an underwater ridge extending from a tip of the island to Landing Bay Pinnacle (35º28.05S 174º44.11W) and is often dived in combination. Boats usually anchor on it, as surrounding waters are rather deep. This is a nice dive because it provides a good mix of medium to deep diving opportunities. In the shallows one encounters pelagic fish like jack mackerel and koheru, and in the deep pink maomao. It is mainly stalked kelp habitat.

inquisitive koheru (Decapterus koheru)
f024704: a diver is surrounded by inquisitive koheru (Decapterus koheru).
lots and lots of two-spot demoiselles
f023630: lots and lots of two-spot demoiselles taking an interest in the diver.
pink maomao and diver
f023625: pink maomao often come right to the top of Landing Bay Pinnacle.
school of pink maomao
f023620: a school of pink maomao resting in divable depths.

Taravana Cave
Taravana Cave is one of the World's large natural wonders, unknown to many because it is so inaccessible. At Butterfish Bay it has two entrances: the main entrance at 32m depth and the 'rat hole' at 26m depth, which is much smaller. To begin here, many would say that the rat hole is a very large underwater cave leading into a large tunnel which soon goes completely dark. But just as one would like to turn back, on the left, the main entrance becomes just visible as a spooky blue halo, guiding the return trip. This dive can be done safely on a single tank, provided one is completely at ease not being able to surface during the entire dive. It is definitely not for beginners!

The main entrance to Taravana Cave is very large, with a white sandy beach at its bottom. From one side one cannot see the other, even in very clear conditions. The top of the entrance is at a convenient diving depth (15m), but its bottom (32m) would soon limit your dive time. Miraculously, the beach teeters over a rocky drop to 40m depth, while the sand stays above.
The problem with this cave is that is so deep and so dark. Only very experienced divers could swim it on a single dive tank, but other problems arise. Already one fifth down the aisle, it is completely dark and one needs a powerful underwater torch to proceed, and a spare in case the main light fails. One cannot see either side when swimming in the middle, even with a powerful 50W quartz-halogen light (a car head light). So one can easily swim in circles. Fortunately the compass keeps working in this underground trap, as it needs consulting all the time.
After a very long swim in the eerie dark, inside a sound shell that reflects all breathing sounds to ridiculous levels, one finds the end, a small dome at convenient diving depth. In most of the tunnel there is no life growing on its walls. Along the northern wall, runs a thin rope placed there by previous explorers. Should things go wrong, this rope could guide you home again, but it runs near the bottom, where dive time runs out quickly.
Read more about this cave in The awesome Taravana Cave.

Phil's Knob
Named after dive veteran and charter boat owner Phil Bendle.
awaiting more information


Butterfish Bay and Maomao Arch
Butterfish Bay is deep with a divable edge all around, of which its southern wall is the most interesting. Here one finds Maomao Arch, a small opening between east and west, through which usually a stiff current flows. Make sure you can make it back again, because swimming all around is not an option. Maomao Arch usually has a dense school of demoiselles swimming in the shade, just with their noses touching the light curtain. For them this is a prime spot where food arrives plentifully, while staying sheltered from marauding gannets and shags.

In this southern wall is a small cove, which we call Butterfish Cove, just enough to park a small boat in for a night dive. Big boulders all around, and fish find this a good spot for bedding down. I've always been surprised at its high biodiversity, and none of the night dives was ever disappointing. This wall and cove must be very sheltered because one finds the coastal flexible weed (Carpophyllum flexuosum) here, as forests of over 4m tall.

large scorpion fish Scorpaena cardinalis
f048314: a large scorpion fish finds food galore as demoiselles find this cove a preferred spot for nesting. Note the flexible weed (Carpophyllum flexuosum) in the background.
coastal jack mackerels
f048330: there are always schools of young fish around. These are coastal jack mackerels finding security in the tall forest of flexible weeds.
a forest of flexible weeds  (Carpophyllum flexuosum)
f048309: a forest of flexible weeds (Carpophyllum flexuosum) clings to the wall, refuge for small fish by day and night.
f033127: a sheltered wall harbours surprises, even in the kinds of seaweed encountered. This is a red seaweed on a rock smothered in sponges.
pink maomao sheltering all around at night
f032935: pink maomao find plenty of resting places on small ledges and the few recesses and small caves.

Twelve Fathom Reef
awaiting more information


Skull Bay
Skull Bay, named after a whale skull once resting in its shallows, provides a large area of shallow and safe diving (and anchoring over rocks). It is covered in boulders that are in turn covered in seaweeds, alternated by bare sea urchin patches. The walls around are steep and dark, with a good variety of life. This spot is also excellent for night diving. Skull Bay is the preferred bunkroom for pelagic schools of blue maomao and trevally that roam the large area around.

a diver herds a large leatherjacket
f026013: a diver herds a large leatherjacket gently towards the photographer. Notice the bottom of Skull Bay is strewn with boulders, covered by seaweed, with plenty of hidden nooks and crannies.
trevally school
f041118: one of the trevally schools frequenting Skull Bay, but it requires much patience and being prepared to swim distances and an ability to free-dive down to 10m.

The Canyon
Just north of Motu Kapiti is a small unnamed shallow patch at 18m depth (Canyon Reef 35º28.27S 174º43.986W), where boats can safely anchor. This barren pinnacle descends steeply on all sides, but towards the island it dips into a 5m wide canyon that runs parallel with the island. This canyon has one dark and one sunlit wall, and descends to 35m where it joins the slope to the undivable abyss. One finds quite a selection of small fish here, like half-banded perches and at the deep end even splendid perch. This is also suitable for night diving, but requires experience because of the depth of the dive. 

red scorpionfish (Scorpaena cardinalis)
f029115: a red scorpionfish (Scorpaena cardinalis) never sleeps and also hunts at night. When a diver disturbs fish nearby, it may provide it with unsuspecting prey.
zoanthid anemones on a dead gorgonean fan
f032822: zoanthid anemones have invaded a gorgonian tree, as if it created the branches itself. By night all polyps are wide open, but they close when catching bugs attracted by the diver's light.
a half-banded perch tucked away in a recess.
f048109: a half-banded perch tucked away in a recess.

Diadema Reef
Wade Doak's description: "Diadema Reef is  between Serpent Rock and the adjacent promontory. I would  find it on clear days by descending the promontory to the sand and then heading west until I saw it loom up out on the sand: Diadema urchins side by side in a row under the ledge at sand level.  I have never seen so many in one place. Long-finned boarfish in schools.  After  exploring the reef, its long axis at right angle to the promontory,  I would  head over to Serpent Rock,  just visible, and ascend there. A very nice dive with a good  cliff wall to decoke on, rather than ascend  directly from the reef in open water. That way I could be taking pix  at all stages of the dive."


Serpent Rock
Serpent Rock juts out from the sand shelf to the steep abyss. It looks like a serpent when viewed from Rikoriko cave. On its southern side, the sand gently slopes away, then fast, to merge into a sloping rock with a garden of beadlet corals (Primnoides sp.) beginning at around 30m deep. On its north-eastern side, it drops away fast into the deep, and at its tip there is a sheer drop to over 50m deep. Here was once a beautiful black coral tree at 36m depth, admired and visited by many divers. But in 1983 it died, when also most demoiselles died. Perhaps one day another tree may emerge?
Most divers will be tempted to do a full circle around Serpent Rock, which is a dive well worth its while. On the west end, there is a shallow shelf with a pinnacle and some caves and shafts. This is a place full of fish of all kind, and one can find pink maomao sleeping upside down under overhangs. It is worthy of a dive on its own merits.
f040636: this female green wrasse lives at the northern face of Serpent Rock and has been there for at least two decades. Whenever I visit the rock, I make a point of looking for her, as she always stays inquisitively nearby. In the meantime she has become a male.

f009936: looking up through a shaft at the deep end of Serpent Rock, with in the foreground a firebrick star. These shafts are very sheltered during storms and are therefore a perfect sleep-out for schooling fish like pink maomao.

Kamikaze Drop-off
Kamikaze Drop-off is a sheer vertical drop from 20 to 80m at the NW corner of Serpent rock. It was a favoured dive to see a large black coral tree, now dead.

Gorgonian Plain
The Gorgonian Plain is found from 40m and deeper at the SW corner of Serpent Rock, where the sandy slope suddenly dips into undivable depths. The gorgonians in question are mainly the beadlet coral (Primoides sp.).

Dutch Cove
Dutch cove is a lovely bowl outside the main currents, with a sandy patch in the middle. It joins a passageway for small boats, in the corner of which is a small shallow cave which goes surprisingly deep over a sandy bottom. A dive here offers a great variety of opportunities, and is also a great night dive. It is favoured by nesting demoiselles and of course their predators. A boat can conveniently be anchored over the sandy patch at about 15m depth.

Hope Point and Airbubble Cave
In the early days of diving, Hope Point was where you followed the ridge down to 50m to find spotted black groupers and large slimy trumpet sponges. This side of the Poor Knights is well lit and fully exposed to storm waves, and can often not be dived upon. In the shallows one finds a small air bubble cave of no repute, but always visited when you are there anyway and have to make a long decompression stop on the way back.


Rocklilly Bay
When westerly winds send a nasty chop onto the west side of the island, the east side can become divable if also the easterly swell subsides. In those conditions, Rocklilly Bay is a place without wind. The bay is wide and affords a shipload of divers, but there is not so much to see apart from monotonous kelp. The bay at Maomao Arch has in this respect more surprises. One can do some snorkelling in the shallows of the bay.