Poor Knights, rich seas
French oceanographer Jacques Cousteau rated the Poor Knights Islands off Northland’s east coast as one of the top 10 dive spots in the world. Twenty-five years after they were gazetted a marine reserve, they remain as magnificent as ever, a place of rare undersea richness where exciting biological discoveries continue to be made.
In hind sight it seems obvious: the Poor Knights should have been a fully protected marine reserve from the start. Instead, the reserve that was created to protect New Zealand’s premier dive location and marine treasure-house permitted fishing in 95 per cent of its area—a matter of considerable regret to many of those who know the Poor Knights best.
Wade Doak, doyen of New Zealand diving, remembers the years leading up to 1981, when the waters around the Poor Knights Islands finally became the country’s second marine reserve, as a period of agonisingly slow progress towards the goal of marine conservation.
“In the context of those times it seemed churlish to cavil over the allowance of recreational fishing,” he told me one evening recently in his Ngunguru home. “It was felt that that amount of fishing was just a sneeze, that it didn’t amount to anything. It was only with time—when the golden snapper and the pink maomao started to disappear—that we became aware that it was dreadful.”
It would take a further 17 years to achieve full protection. Not until 1998 would charts of the Northland coast show crossed-through fish—symbols for “no take”— around the entire Poor Knights group. At last, divers had something to celebrate: the islands had become a “proper” marine reserve.
The act of parliament that legislates the creation of marine reserves was passed in 1971 in order to protect areas of New Zealand “that contain underwater scenery, natural features, or marine life, of such distinctive quality, or so typical, or beautiful, or unique, that their continued preservation is in the national interest”.
Under these terms, the Poor Knights instantly qualified for consideration. Whereas Goat Island, New Zealand’s first marine reserve (created in 1975), represented a typical stretch of Northland coast, the Poor Knights were anything but typical. “Distinctive quality”, “beautiful” and “unique” could have been penned specifically with the islands in mind.
The Poor Knights group—two large islands (Tawhiti Rahi and Aorangi) and ten small—stretches in a 10 km north–south line 24 km off the Whangarei coast. The islands occupy an oceanographic intersection between temperate and subtropical waters. They have some of the country’s lushest kelp forests—a signature habitat of temperate seas—but are also renowned for sightings of such subtropical and tropical icons as cowrie snails and corals, giant salps and paper nautiluses, and gaudily coloured fishes, shrimps and sea urchins. Even turtles and manta rays have been seen.
Such a combination of ecological assets made the Poor Knights a logical choice for a marine reserve, and moves in that direction were started the year after the act was signed into law.
Curiously, two separate marine-reserve applications were made, one by the Environmental Defence Society (probably stimulated by the granting of a concession to prospect for oil near the islands) and one by the Hauraki Gulf Maritime Park Board. Both sought a reserve that would extend eight kilometres offshore.
The Marine Department turned down the applications, citing three reasons: first, the area extended into the high seas, making it too large and putting it beyond the department’s power to consider; second, reserve status would unduly interfere with commercial fishing; third, a marine reserve as constituted under the act would bar recreational fishing, which would be contrary to established interests and curtail charter-boat businesses.
And so the horse trading—or fish trading—began. In exchange for two small no-take areas encompassing the most popular dive sites (amounting to five per cent of the area of the proposed reserve), anglers retained the right to fish for certain species (snapper, trevally, kingfish, kahawai, shark, billfish, barracouta, tuna, mackerel and pink maomao) using certain methods (trolling, spear-fishing and floating lines) around the rest of the islands. The boundary of the marine reserve shrank from 8000 to 800 metres offshore, and there it has remained.
Lew Ritchie, a marine biologist who worked with the former Ministry of Agriculture and Fisheries, the arm of government that took over marine-reserve applications when the Marine Department was dissolved in 1972, says pragmatism ruled the day. “It wasn’t quite a case of the moon or sixpence, more like the moon or fifty bucks [in that there were two no-take areas]. It was clear we weren’t going to get the moon, so we took the fifty bucks.”
Inevitably, the compromise pleased no one. Among those who kept pushing for a total fishing ban was Jeroen Jongejans, who started a dive company at Tutukaka in 1992. He is now a director of Dive Tutukaka, the largest Poor Knights dive operation.
“We had people from overseas diving in what was supposed to be a marine reserve and next door to you people were hauling up fish, and often they were reef fish. It just didn’t make any sense,” he told me.
The no-take/partial-restriction partition resulted in all sorts of tensions. “The pressure from recreational fishers increased, but many of them didn’t know the areas where they could or could not fish, or what type of tackle was permitted. And it was hard to police what was happening because the islands are so far offshore.
“I was quite involved in the lobbying at that time. One compromise that was suggested was to make Aorangi a total reserve and continue to allow fishing around Tawhiti Rahi. But even reef fish move around, and some of the best dive sites are around Tawhiti Rahi, so we decided to go for the whole thing as a no-take reserve.”
Several years of acrimony and a High Court judicial review later, divers didn’t just have their fifty bucks, they had the moon.
For me, what is distinctive about the Poor Knights is I dive in them, not at them,” writes Wade Doak in City Under the Sea, a not-yet-published book that will soon join the nearly 20 titles he has produced over the course of half a century of scuba diving.
Doak’s comment refers to one of the Poor Knights’ most dramatic geographical features: the dozens of arches, caves and tunnels that make diving at the islands an architectural as much as a biological experience. The arches in particular are favourite dive sites because of the concentration of fish and filter feeders in and around them, a result of the constant through-flow of water and plankton.
Shoals of blue maomao and demoiselle are permanent residents of these rocky portals, the maomao hanging in masses like turquoise chandeliers in mid-water, the inquisitive demoiselles (French for “young ladies”) darting about like sparrows. Triggerfish, comical and fearless, glide on undulating fins, eyeballing the diver then angling away, perhaps to nibble on a jellyfish. Snapper of sizes that would make an angler weak-kneed cruise around the arch entrances. In summer, stingrays form pancake stacks of up to 100 individuals, their wing tips beating rhythmically as they maintain a group holding pattern.
Of the 16 caves dotted around the perimeter of the islands, the most impressive is Rikoriko, believed to be the world’s largest sea cave. With the ceiling at its highest point 35 m above the water, the sea-floor at its deepest 26 m below, a length of 130 m and a maximum width of 80 m, Rikoriko can accommodate several boats—and, during storms, sometimes has. A Japanese submarine is said to have hidden in the cave for two weeks during World War II while undergoing repairs.
Before the islands became a marine reserve, game-fishing skippers would impress their clients by driving into the cave at trolling speed with outriggers out and baits down, executing a tight turn inside and driving back out into the sunlight.
Rikoriko Cave has also served as a natural sound shell for rock-music sessions (Neil Finn and Herbs have been recorded there), and Doak once used its whitened dome as a screen for projecting slides.
Perhaps the most unusual of the Poor Knights’ caves is Airbubble Cave, which, as its name suggests, contains a pocket of air trapped against its ceiling. In fact, there are two bubbles, one of which is large enough for divers to stand up in and breathe. (Dive etiquette demands that those who breathe from the bubble should replenish it with a few puffs from their tank before departing.)
The islands’ caverns and archways are the handiwork of the sea, shaped over thousands of years of wave-pounding during the ice ages, when the sea level was up to 120 m lower than it is now. Today, diving down the undersea cliff faces of the Poor Knights to the sand 50 m below is, says Doak, “like descending a staircase to an ice-age beach 15 storeys below.”
The islands themselves are the eroded remnants of a volcano that erupted between 2 and 10 million years ago. Similar rhyolitic outbursts produced the Mokohinau Islands, Great Barrier Island and the Mercury Islands. By some estimates the original volcanic cone was 25 km in diameter. A thousand metres of rock is thought to have been eroded off its top since volcanic activity ceased.
The distinctiveness of the Poor Knights’ underwater flora and fauna arises from the fact that the islands lie near the path of the warm East Auckland Current, which originates near Lord Howe Island and follows the approximate edge of the continental shelf down the north-eastern coast of the North Island. This southward-flowing conveyor belt of tropical water affects the Poor Knights more strongly than it does any other offshore islands, delivering an assortment of warm-water organisms to their neighbourhood.
Many of the incoming creatures are temporary visitors, but some take up permanent residency. A survey published in 1982 found that a quarter of the fish species encountered at the Poor Knights were not common along the adjacent Northland coast, where the water temperature is typically a degree cooler than it is round the islands.
Among the exotic fish residents—many with suitably exotic names—are blue knife-fish, gold-ribbon grouper, striped boar-fish, Lord Howe coral-fish and common and lavender lizard fish. Cone shells, frog shells, moon shells, egg shells and triton are a few of the warm-water molluscs which turn up at the Poor Knights, along with various species of cowrie. Among the tropical crustaceans which find a southern home at the islands are Spanish lobster and the dainty red-banded coral shrimp.
Two fairly consistent spring visitors borne along on the current are the paper nautilus and the giant salp, sightings of which are eagerly sought by divers. Paper nautilus shells have sometimes been found in large numbers on the eastern side of the Knights, heaped up in rocky culs-de-sac by the prevailing easterly swell. These fragile white creations are not true shells at all, but protective brood chambers secreted by female cephalopods known as argonauts. The female argonaut lives within her “shell” (which in some species reaches 30 cm in length), brooding her embryos and spawning them at intervals into the water. The male argonaut is a piffling creature, a mere 10 per cent the size of the female.
Empty brood chambers are all that are usually found at the Poor Knights, but occasionally living females are seen. They typically don’t live for long, as many fish—especially kingfish—prey on them.
Looking like massive gelatinous socks, giant salps are pelagic relatives of sea squirts. Some are so large that divers can fit comfortably inside them. A single salp is made up of thousands of individual filter-feeding animals grouped side by side so that they all pump water into the centre of the sock, giving the colony a modest degree of propulsion.
By the time these tropical drifters reach the Poor Knights they are generally the worse for wear, well-holed by hungry fish.
For the 1960s scuba pioneers of the Poor Knights, every dive brought the possibility of finding species not just new to New Zealand but new to science. “We were like the first guys on the moon,” says Doak, “except this moon had life.”
Whangarei jeweller Bill Palmer (now living in Auckland) was particularly adept at spotting new and rare species. He discovered 13 new species of mollusc, three of which were named after him, and the rest sea urchins. On one occasion, in 1963, he found some rare orange-flecked cowrie shells at 30 m. For safekeeping he put them inside his mask for the duration of the dive.
One of the echinoderm species with a palmeri ending is the spectacular diadema urchin. Doak describes the find in his book The Cliff Dwellers:
In the twilight blue 130 feet down . . . Palmer noticed a strange dark sea urchin. Between the long spines blue lilac bands seemed to fluoresce with magical pulsations. Careful of the sharp spines he lifted it up on his steel cray hook and balancing it there, rose to the surface. To his astonishment, the sombre colour began to lighten as the surface light increased: from black, to ruddy brown and bursting through to the sunlight, a brilliant ruby red.
Diadema palmeri, whose closest living relative is in New Caledonia, is regarded as a must-see species for Knights divers. Must see, but mustn’t touch. The needle-sharp spines, which swivel in the direction of movement when a shadow passes over the animal, are poison-tipped, as Lew Ritchie discovered to his cost.
“I took some friends to see the black coral trees at Imagination Point,” he told me. “Before long they were crashing around in the branches, narked out of their one-cell brains because they hadn’t done much deep diving for a while. Narcosis [“rapture of the deep”] is something you get inured to if you dive regularly enough—you can work at 150 plus feet quite happily. I was worried that they were going to damage the coral, so I retreated along the wall, hoping they would follow. I put my hand out to steady myself in the current and put it right on a diadema. The pain was utterly exquisite. It was like an explosion. I looked at my fingers and there were black dots where the spines had broken off. By the time I got back to the boat the top two joints of my fingers were black. We had nothing on board except some sun cream, which contained a mild painkiller, so we smothered my fingers with it and bandaged them. A couple of hours later, when I took off the bandage, I thought I’d be looking at white bone, but actually the black had faded, and so had the pain.”
Deep dives—up to 60 m—were an accepted part of the trailblazing era of Poor Knights diving, though today few sport divers would risk such deep descents. “At that time it was all unknown territory, so the inducement was huge,” Doak says.
Many of the Poor Knights’ greatest treasures lay at the limits of diving range. Black coral trees were one of the most prized sightings: ebony trunks and branches covered with a ghostly white fuzz—the coral polyps—and entwined and encrusted with gorgeous brittle stars, bryozoans, sponges and anemones. The largest measured 4.6 m from its base to the tip of its longest branch—thought to be a world record. Most have now disappeared, lost to disease or snapped off through entanglement in crayfishing gear prior to the establishment of the marine reserve.
Stands of giant tube and organ-pipe sponges were another invertebrate spectacle that is now a rarity. Fortunately, photographs exist to show the splendours of that era. Underwater photography was just starting to come into its own in the 1960s, so not only could divers observe and describe the denizens of the deep, they could bring back the visual evidence.
Kelly Tarlton’s pictures regularly graced the pages of early Dive magazine articles on the Poor Knights. Tarlton, who started diving in Canterbury with Doak in the 1950s, built his first underwater camera housing out of sheet copper and Perspex. “It leaked like a sieve,” he wrote. “I had a piece of blotting paper stretched between two contacts. When it got wet, a buzzer rang and it was time to come up.” He later made a housing for a 16 mm movie camera out of the propeller dome of a DC-3 aircraft.
Diving at the Poor Knights during the 1960s and 70s wasn’t just about finding and photographing new species. For Doak, Ritchie, Tarlton, Palmer and others in that “band of fanatics”, as Doak calls them, learning how marine ecosystems functioned was as important as recording their existence. Hundreds of hours were spent observing fish behaviour, one species of special interest being Sandager’s wrasse—at that time called Sandager’s parrot-fish (Sandager being the name of the lighthouse keeper who discovered the species).
Like all wrasses, these fish start life as females, and only later do some undergo a sex change—and a profound colour change, from demure salmon to a riot of bright brush-strokes reminiscent of a Kandinsky painting.
To investigate social hierarchies among these wrasses, Doak and his companions used mirrors to assess the aggressive response of individual fishes. They also towed wooden replicas of various species across the fishes’ territories to see how good they were at pattern recognition.
In City Under the Sea, Doak records how they found the answer to a particularly puzzling question: Where do Sandager’s wrasses sleep? The divers had observed that, at dusk, the wrasses congregated near rocky reefs, and seemed gradually to disappear into the interstices of the reefs. But when the researchers made night dives and explored these crevices they could never find a single wrasse.
Then someone began delving with their hand in the coarse sand under a ledge, and withdrew it with a shock—an involuntary reaction at touching something moving. Further probing, and the sand seemed to smoke in a straight line. Something was wriggling beneath it. Suddenly a sand storm erupted and four female Sandager’s wrasses leapt out and dashed off into the dark, crashing into rocks in their blind panic.
Mystery solved: at night, Sandager’s wrasses bury themselves under several centimetres of sand.
The Poor Knights remain a popular research destination for scientists, though their remoteness adds considerably to the cost of working there. Soon after the islands had gained full marine-reserve status in 1998, University of Auckland PhD student Chris Denny commenced a study examining the effect of the reserve on fish populations. He found that between 1999 and 2001 snapper abundance increased 14-fold, a result consistent with what had been observed at Goat Island after it had been declared a marine reserve in 1975.
Four other species (blue and pink maomao, porae and orange wrasse—the first three of which were targeted by fishers prior to the no-take era) also increased in abundance during the study period, but the density of a further seven species, including red moki, goatfish and spotty, declined, perhaps as a result of their being out-competed or predated by snapper or other recovering species.
Denny notes that one must be cautious when attributing population changes in non-targeted reef-fish species to a “marine reserve effect”, because the fortunes of these species are tied to the vicissitudes of sea temperature, currents, storms and larval recruitment.
Agnes le Port, a French PhD student at Auckland University, is currently studying stingrays at the Poor Knights. I met her at the islands in January 2006 aboard the university’s research vessel, Hawere. A few minutes before our rendezvous, Hawere had haemorrhaged hydraulic fluid into its bilges, putting its dive compressor out of action and bringing the trip to an unscheduled early end. Nevertheless, we made one dive—she with a tagging pole, an assistant with a biopsy pole, me with a camera—looking for stingrays at the southern end of Aorangi. Perhaps the boat problems were prophetic: we saw no stingrays.
Weather and boats permitting, le Port dives every month at the Poor Knights and other locations, recording stingray numbers, tagging individuals and taking biopsy samples for DNA analysis. Tracking seasonal variation in the Poor Knights’ stingray population (high numbers in summer, low in winter) is one aspect of her project. She hopes to find out what factors trigger the ray aggregations (resulting in the pancake stacks seen in some of the Poor Knights’ arches) and where the animals disperse to. Are the aggregations related to mating activity, as has been assumed, or is there another cause?
Le Port is also examining populations of the same species of stingray elsewhere in New Zealand and the Southern hemisphere to see if they are parts of one contiguous breeding unit, or if there are separate regional groupings that are reproductively isolated.
Another research project that is under way at the Poor Knights is a four-year investigation by the University of Auckland and the National Institute of Water and Atmospheric Research (NIWA) into the impacts of ecotourism on the islands’ marine environment. The main question the researchers want to answer is: What level of human activity can the islands sustain before degradation starts to occur?
In November 2005, NIWA staff mapped the reefs and sediments around the islands using a multi-beam echo sounder. Mark Morrison, one of the project organisers from NIWA, said this was the first step in a process that would result in a high-resolution map of the islands’ marine habitats.
“The multi-beam data gives us a 3-D model of the physical environment—all the canyons, pinnacles, rock stacks, arches. The only thing it can’t do is give us the interior of the caves, because the acoustic beams don’t go round corners. From the back scatter we get an idea of whether the substratum we’re looking at is rock or sand or a bed of calcareous rhodoliths, or some other type of material.
“The next stage, which will happen in 2006, is to use a towed underwater video camera to gather information about the plant and animal assemblages. We will then drape the biological communities over the physical terrain, and end up with a map of the whole habitat.”
Once the ecological resources of the islands have been determined, the researchers will try to measure the effects of tourism, especially at high-use sites, looking at everything from direct physical impacts (damage to, or dislodgement of, species by divers and anchors) to less obvious effects such as behavioural changes in fish, marine mammals and sea-birds.
The ultimate aim is to design a set of management protocols that can be used nationally and internationally to minimise the impacts of tourism on the marine environment. “It’s about maintaining a healthy tourism industry while at the same time protecting the values on which that industry is based,” says Morrison.
The local dive industry is involved with the project, providing information on tourist usage of the islands and commenting on social factors such as diver expectations and reactions. Says Dive Tutukaka’s Jeroen Jongejans, “We want to be seen as a sustainable industry that takes nothing from the environment.”
For his part, Jongejans would like to see marine conservation become even more deeply entrenched in Northland. He has recently promoted the idea of a marine national park from Cape Brett to Whangarei Heads. “Ten per cent would be marine reserves and the rest would be for recreational fishing, but with half-bag limits. Commercial fishing would be banned.”
Jongejans doesn’t expect the idea to come to fruition without a long battle—no marine-conservation initiative has ever enjoyed plain sailing in New Zealand. But he is adamant that ecotourism is the future for Northland.
“The no-take reserve at the Poor Knights is a win-win situation both for ecology and the economy,” he told me. “Research shows that one third of dive-visitor expenditure goes into the dive trip and two thirds goes into accommodation, transportation, food and entertainment. If the dive industry at Tutukaka is worth about three million dollars, then the benefit to the local economy is close to 10 million. This is a pretty good argument for why we need more marine reserves around the country.”
Jongejans hopes the Poor Knights will eventually become a World Heritage Site, though he has no illusions that that process will be a straightforward one. “When I put it to regional council some years ago they wouldn’t support it because there are Maori ownership and management issues relating to the islands that remain unresolved.”
Meanwhile, tourist numbers at the Poor Knights are up 50 per cent since 2000, and anecdotal evidence suggests that charismatic species such as hapuka, kingfish, trevally and packhorse crayfish are on the rebound.
“We’re also starting to see the top predators again,” says Jongejans. “In winter, when the water clarity is at its maximum, I can jump in at Cream Gardens and see 30 to 40 bronze whalers. The whole feel of the islands is much better now.”
In January 2006 while writing this story, I dived at the Sugarloaf, the towering, sea-scarred fist of rock that marks the southernmost link in the Poor Knights chain. The sea was calm; what swell there was sucked at the skirts of red and brown seaweed fringing the shore. Gannets, as tiny as toy aeroplanes, wheeled in endless circuits around the top of the island, white flecks against a cirrus-streaked sky.
I slid into the water and into a school of‚ perhaps 200 kingfish. Counting was futile; they moved too fast in their three-dimensional liquid space. I hadn’t seen that many kingfish since my student days in marine biology 30 years before, when I had dived among these regal animals at the Three Kings.
A promise of abundance to come, as Poor Knights populations adjust to the absence of fishing pressure? I hope so. My grandfather, a swordfisherman, used to speak of unbroken schools of trevally and kahawai stretching from the Cavalli Islands to Cape Brett. We may never see the like of those schools again, but the Poor Knights marine reserve, small as it is, should prove a worthy time capsule.