Poor Knights

Forest and Bird, Issue 307, 1 February 2003, Page 25

Poor Knights

CHRIS DENNEY

The marine life around the islands slowly diminished over the years since we first dived there in the 1970s. Trevally schools that covered acres of ocean were common but vanished just prior to the decision to protect the islands as a marine reserve in 1981. Protection was not absolute, however — the Poor Knights became the only marine reserve that allowed limited fishing. Then, in 1997, Hon. Dr Nick Smith, as Minister of Conservation, defied all expectations and declared the Poor Knights Islands a totally protected marine reserve. Within six months of the Minister’s decision we began to see snapper on every dive. Porae and tarakihi numbers also increased. (See more in box about Increased Fish Numbers.) Recently the trevally schools have begun to mass and feed on the surface again.

The schools are not as large as 25 years ago but make a spectacular sight. A thousand mouths opening and closing in unison is unforgettable. Life in these waters is returning to what it was before fishing and collecting pressures began the downward spiral. The vertical walls that surround the islands are covered in lessonia and ecklonia kelp. Around the holdfasts, where the kelp joins the rocks, the colourful invertebrate life begins. Jewel anemones in every colour imaginable are joined by white common and red waratah anemones. Between them patches of orange and yellow encrusting sponge dominate. Blennies and triplefins sit amongst the sponges or peer from holes in the rock. Sea shells, like the tiger and trumpet shells found elsewhere in New Zealand, sit in the cracks. Other shells, like the fawn

and white spotted Pacific deer cowrie, are migrants from the tropics. In the 1970s the find of a similar shell, Tomlin’s cowrie, created excitement although it has not been recorded since the 1980s. The largest and most beautiful helmet shell, the royal helmet, recently reappeared after an absence of more than 20 years. Five species of moray eel are found at the Poor Knights, with the needle-toothed mosaic morays the most spectacular. We have seen an increase in moray eels since 1997, although they should not have been affected by the changes in the islands’ reserve status. Either there is more food for the eels now or the earlier regulations banning weighted fishing lines were being ignored. The open-mouth stance that gives morays such bad press is actually their method of breathing. Water passing over their gills provides oxygen and the open mouth enhances the water flow. At 20 metres on the sand at the entrance to Rikoriko Cave another predator lurks. Lizardfish with serpent-like bodies lie waiting to prey on triplefins and crabs. Their patterned brown bodies camouflage them against the sand, but they change to red under torchlight. A lilac lizardfish, similar in size can only be separated from its red cousin when lit. Living at the bottom of the cliff is an animal almost in the ‘see it to believe it’ category. The needle-spined Palmer’s diadema urchin, is related to the common kina or sea egg. Its spines and body glow crimson in our torchlight while flashes of fluorescent blue pulsate across its body.

Another less colourful migrant, Savigny’s urchin appears occasionally but has not colonised. Pairs of striped yellow-and-black Lord Howe Island coralfish cruise alongside the walls, darting under the kelp to hide. As the name suggests they are usually found around coral reefs, rather than kelp forests and temperate waters. Yet these fish are breeding at the Poor Knights Islands and are now found as far south as White Island in the Bay of Plenty. Combfish, crimson cleanerfish and juvenile Sandager’s wrasses perform parasite-cleaning duties for other fishes. Two-spot demoiselles hover, gills open and fins extended, as the cleaner fishes work to rid them of parasites. Two other species, the single-spot and the yellow demoiselle, migrants from the subtropics, often mix with the two-spot variety. In the 1970s a small, brightly-coloured cleanerfish, aptly named the rainbow wrasse was recorded. During 2001 we saw them again, with both males and females providing a ‘cleaning service’ for other, larger fish. Sharp-nosed pufferfish or toado hover over the kelp forests. Pufferfish are identified by their box-like shape and vivid blue markings. Other tropical migrants, like the lionfish seen in 1990, survive only until the cooler waters of winter arrive. Half-banded perch are camouflaged amongst the invertebrate life. Their bright green eyes swivel watching for triplefins that may stray too close. Toadstool groper, their orange bodies patterned with white spots, hide in caves. Large eyes give an indication of their nocturnal habits. Recently several hapuku returned to the deep crevice known as The Slot, at the

Pinnacles. They quickly vanished, however, replaced by evidence of illegal fishing — weighted lines tangled in the rocks. Gold-ribbon groper, yellow-banded perch and the larger spotted-black and Queensland gropers are seen infrequently. While the spotted-black groper is protected under the New Zealand’s Wildlife Act, the Queensland groper only has protection inside New Zealand’s marine reserves. It grows to three metres long and is protected almost everywhere outside New Zealand. Maybe the protection afforded by the Poor Knights Islands Marine Reserve will allow some of the larger gropers to re-establish. Schools of porae are returning, especially noticeable in Barren and Middle Archways. Above them masses of pink maomao face into the current feeding on planktonic particles. In summer hundreds of short-tailed stingrays cruise gracefully up and down the walls of the archways. Recently they have been joined by bronze whaler sharks attracted by increased fish numbers. The shark most commonly seen is the carpet shark. It is small and harmless, usually found amongst the boulders and invertebrate life in spring and early summer. The fishermen may have been branded as the villains in the reserve’s history but it was the fishing clubs that originally pushed for reserve status for the islands. Since the marine reserve was gazetted charter-boat skippers have é actively policed the reserve. For many fishing-charter operators, total protection of the marine reserve has brought a decrease in patronage, forcing some to move to the Bay of Islands.

On the other hand, an increase in divers and sightseers has boosted the patronage of boats that take those who just want to look. The change in visitors to the Poor Knights Islands Marine Reserve from ‘takers’ to ‘lookers’ must be a benefit to the marine life. It is also a guarantee that the islands’ unique biodiversity is protected for future generations. — TONY AND JENNY ENDERBY are photojournalists who specialise in underwater photography. Their latest work is a Lonely Planet guide to New Zealand dive sites (see Book Notes in this issue).

Increased Fish Numbers Scientists from the University of Auckland’s Leigh Laboratory have monitored fish numbers at the Poor Knights Islands Marine Reserve using baited underwater video equipment (BUV). Snapper and tarakihi numbers increased notably in a very short time after total protection. From the BUV data there were 16 times more legal-sized snapper in the Poor Knights Islands Marine Reserve in April 2002 compared to Sept 1998 (pre nontake status). There was no increase at the two reference sites (Cape Brett and the Mokohinau Islands). At the same time, the mean snapper size at the Poor Knights increased from 297 to 337mm. There was no change in the mean snapper size at the two reference sites. From the underwater visual census, snapper, pink maomao, porae, golden snapper and koheru all showed an increase since the full protection was implemented.

Leigh Marine Laboratory.

Poor Knights Islands

The Poor Knights Islands appeared during the Pliocene period some 13 million years ago. They were originally part of the mainland, separating around 120,000 years ago and are the lava domes of ancient volcanoes. There are two large islands, Tawhiti Rahi to the north and Aorangi to the south, and many smaller islands. The Pinnacles group and the Sugarloaf, some miles to the south, are also part of the marine reserve.

Maori were the original inhabitants with approximately 350 Ngatiwai and Ngatitoki living on the main islands. The steep cliffs have few landing places which made the islands easy to defend.

Poor Knights Islands Marine Reserve

Maori lived there until 1823 when the chief Tatua left with his warriors to join Hongi Hika in his musket wars with tribes further south. During their absence a rival Waikato tribe, attacked and wiped out all but a few of the inhabitants. On his return, Tatua declared the islands tapu, effectively stopping any further landing by Maori and they have remained uninhabited since. The islands were classed as a wildlife sanctuary in 1929. The waters around the islands were declared a marine reserve in 1981, but limited fishing was permitted until the islands gained total protection in October 1998.

We were diving inside Blue Maomao Archway, at the Poor Knights Islands Marine Reserve. The archway, just off Labrid Channel, flows into South Harbour and the sights are typical of the rich and diverse life of the Poor Knights Islands. A curtain of blue maomao parted as we swam towards them. They closed behind us and we were surrounded by a moving wall of fish, so organised they could have been choreographed. Dozens of two-spot demoiselles flitted over the rocks below us and red pigfish, Sandager’s, banded and

scarlet wrasses hovered like interested spectators. The rocks and walls completed the stage with a backdrop of colourful invertebrates. Anemones, sponges, bryozoans, hydroids and ascidians covered everything. Splashes of contrasting colour among them were grazing nudibranchs. (See Forest and Bird November 2002). A scorpionfish, like the villain in the scene, watched with expressionless eyes. It raised its dorsal fin and changed from brown to bright red in our torchlight.