• symptoms of decay: clear symptoms of environmental degradation at the Poor Knights
• the snapper-urchin-kelp myth: shoddy science has led us astray on an important ecological issue.
• other symptoms of decay: international scientists have described a scenario of symptoms arising from eutrophication.
• cycles and trends: massive fish mortalities have occurred every nine years since 1983.
• declining fish stocks: although there are more snapper, most resident fish have declined steeply.
• supporting chapters:
• Introduction to marine reserves: a no-nonsense introduction to marine reserves and how they fail (15p)
• Frequently Asked Questions: your fast-track course on marine protection in NZ. (32p)
• The disappearing fish act: a record of the 1992/93 fish mass mortality (3p)
• Timeline of degradation events in New Zealand: fish mortalities and more (2p)
• Decay and degradation: examples of marine degradation in NZ, the full theory and measurements. The work of Dr Anthoni explained. (large)
• myths7: serious questions about the science of marine reserves (24p). See also the myths index. (large)
• myths11: DOC publishes the monitoring results of marine reserves, and it does not look good. (19p)
• marine science exposed: a dissection and critique of shoddy marine science done in NZ. Important for understanding the barren habitat zones. (32p)
• Hauraki Gulf marine survey: an extensive investigation of the kelpbed deaths of 1993, by Dr Anthoni. (20p)
• Storm barrens of NZ: a pictorial overview of NZ's storm barrens (urchin barrens). (12p)

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 --
Rev:20070924,20071027,

First we will show some images, all taken at the Poor Knights, of what degradation looks like. Remember that degradation is about disease and death without successive recovery, or incomplete recovery. It is about living organisms disappearing, which is not easily seen, for how can one see what is no longer there? Therefore the sick organisms are more important than their numbers suggest. A sick sea urchin will vanish in a week's time, usually without trace. If only one in a hundred urchins shows sickness, it could already signal a seriously declining situation, for in 50 weeks half the population could disappear.
 
 

Let's look at the stalked kelp first (Ecklonia radiata), for it occupies such a dominant habitat space in New Zealand. Its upper boundary is determined by the worst waves which simply remove it occasionally. In its place thrives a very productive community of short and almost invisible algae, grazed by sea urchins and molluscs, and also by fish. These barren zones occur wherever the sand bottom is deeper than 15m. At the Poor Knights some of the barren zone is occupied by the very strong strapweed (Lessonia variegata). The deep boundary of the kelp forest is determined by lack of light, due mainly to the limited underwater visibility of the water. At the Poor Knights this boundary used to be 36m deep on shores facing north towards the sun. In recent years it has been shifting upward to 27m, which amounts to a substantial change in the marine environment, all due to declining water clarity. The diagram shows how the marine habitat zones shift while both quantity and quality of life diminish. On left the situation in clear water, with healthy organisms, deep zones and high biodiversity. On right a highly degraded shore with low densities and low biodiversity.

Seaweeds are always good indicators of marine degradation because they stay in one place, are not fished and they are usually quite hardy. So they are not showing the very first signs of degradation, for which sponges are more suitable. But seaweeds produce slime, and when they don't, they are sick, which can easily be tested by any amateur.

So one sees mature plants in trouble, but isn't it natural that the old eventually die? True. Therefore the young ar much more important. As the old die, they make room for the young who compete for their place. So there are always many more young ones than old ones, and it so happens that the young ones are more sensitive to disease and bacterial attack than the old ones. When looking for degradation, always ask "where are the young ones?".
When one sees an open kelp forest, it must be covered in young plants. When seeing a Sandager's wrasse, immediately look for the young ones of which there should be at least ten times as many. Where are they? Where are the young wrasses, angelfish, butterfish, urchins, seastars, crayfish, . . . .?
 

f045327: it is only 15m deep at the bottom of Nursery Cove, and the kelp is in such poor condition that it cannot fend off (slime off) encrusting sea mats (bryozoans). These leaves do not feel slimy any more.

f046123: at the same location, a few months later, most kelp plants have disappeared, and those remaining now are dead but still standing, covered in encrustations and algae.

f042708: on the north-facing wall of Rikoriko, the kelp boundary is retreating to above 30m. This photo was taken with flash light to show the poor condition of the kelp (dark brown and tattered). These plants are not dying - they are dead already.

f042706: the same place as on left, but without flash. One can now see in the distance, a poor 15m. Clearly the kelp forest is dying because there are no young plants to take over. The lower kelp boundary has shifted from 36m to 27m!! A whopping habitat change. Next year, these symptoms will have disappeared, as the boundary has shifted.

f051211: the red fretsaw weed (Vidalia colensoi) is not slimy but is very tough, able to grow in the barren zone. It also resists grazing by urchins, and has little food value.

f046134: this red fretsaw weed is not sick but dead, even though its woody skeleton may persist for a long time. Remember that the sea does not have strong wood-decomposing fungi, such as found in soil.

f046121: a male Sandager's wrasse with a serious case of white rot (probably a fungus). In an aquarium, this fish has only one more week to live.

f046132: a female Sandager's wrasse with the beginnings of white rot, but she may still survive.

f049026: leatherjackets are often seen with a black skin disease, particularly at outer islands like the Poor Knights. It is not certain whether this is a recent symptom. But a fact is that their numbers have declined steeply.

f046133: a grey nipple sponge (Polymastia sp.) with a serious case of rot, which they usually can't conquer. A sponge like this will vanish within ten days. Note how it has contracted to a hard mass, a sure sign of sickness.

f042719: a yellow nipple sponge (Polymastia croceus) in a serious state of decay. When such sponges are not happy, they contract into a hard mass. Happy nipple sponges are fluffy.

f048510: a rough antler sponge (Iophon proximum) showing black rot, is one of many in Butterfish Bay.

f035407: yellow zoanthid anemones invading a grey sponge who has lost its ability to defend against this. Zoanthid anemones used to be rare, but are now very common, a sign of degradation. Degradation can look beautiful.

f045325: the grey ancorina sponge (Ancorina alata) is one of the hardiest sponges in NZ, yet it can become overpowered by marine phytoplankton, suffocating it, as shown here.

f043409: a beadlet coral (Primnoides sp.) being invaded by encrusting sponges and other invading organisms. This can be an entirely normal event, but seeing many affected like this, raises alarm.

f043418: normally when a large sponge dies, it leaves an empty spot in the tapestry of life, and these spots can be recognised. However, in a very short time, opportunistic fast growing species like these yellow bryozoan mats, cover such empty spots.

f043419: yellow bryozoan mats overgrowing vacant territory, caused by a shift in habitat boundaries. (Middle Arch).

f043435: we see more invasive species like these fast growing grey seasquirt mats. Of course there will always be winners and losers in the competition for space.

f051135: although not being threatened for over twenty years, crayfish have not returned. Where are the young crayfish that one should see on every dive?

Note that the above examples document but a tiny fraction of what any diver can find in a few dives.

The snapper-urchin-kelp myth Much ado has been made about sea urchins inside marine reserves, and the myth goes like this: sea urchins eat kelp, reason why there are barren zones in the sea. But in marine reserves the snapper grow so large that they can eat sea urchins. With fewer sea urchins, the kelp returns. Urchins bad, kelp good. Unfortunately this is one of the worst misadventures of marine science, and has been debunked extensively by us, based on their own work and our investigations. But a myth persists for a long time, still enthusiastically spread by marine reserves advocates of which the Department of Conservation is most guilty. Now children at school are learning this. The drawing shows what this myth has led to: without complete marine protection, snappers are caught, which allows sea urchins to multiply unchecked. These prickly grazers attack kelp and in doing so, clear the kelp forest. The underwater productivity decreases, and many kelp-eating fish disappear. Inside marine reserves, however, the big snapper clean out the urchins, the kelp returns, and with it kelp eating fish. Crayfish also become bigger. These big fish produce more spawn, which is exported by ocean currents.

The problem with this attractive narrative is that it is entirely false. It is true that the urchin barrens in the Goat Island marine reserve (and Tawharanui marine reserve) have been overrun by kelp, but this happened also outside marine reserves. In fact, now in 2007, it has happened in most of the entire east coast of the North Island. What scientists fail to mention is that in 1993 the whole kelp forest disappeared, between 1995-1998 the sea urchins, and in 1998 the crayfish. It shows overwhelmingly that a marine reserve is not capable of protecting marine biodiversity, let alone save the sea. Reader, notice in this respect that we at Seafriends fight to save the sea, not to put marine reserves in that won't work!

There is obviously something happening that we don't understand, and this has been Dr Anthoni's focus for the past twenty years. It has resulted in epoch-making discoveries of the most basic ecological laws of our planet. Follow the links above to learn more.
 

f042803: an urchin folding its spines is almost a sure sign of ill health. In fact, the animal inside can already be dead and stinking, while the spines and tubefeet outside appear normal!

f045234: sea urchins have grouped together as they are grazing their patch, fully exposed to potential predators. In the distance, the green sea lettuce is taking over. We should ask ourselves, where the kelp-eating fish are that keep sea lettuce trimmed to a fine mat.

f045221: seaweed is food and if it is not eaten, it will go to rot. Here the green sea lettuce is rotting away because grazing fish and urchins are no longer there to trim it back.

f045224: shards of rotting sea lettuce leaves, looking like soaked toilet paper. Where rot sets in, like the one rotten apple in the fruit bowl, others become infected. More seaweed means more rot and more deaths.

Here is how international scientists describe the symptoms of worsening eutrophication, in order of severity:
 

Notice that one symptom is the appearance of gelatinous zooplankton (jellyfish). The Poor Knights have always been awash in jellies of all kind, particularly while conditions were still excellent, in the 1960s. And now we do not see those salps and jellies as much as they used to. What is going on?
As a photographer I am keen to document the many types of jellyfish frequenting our seas, but in the past decade they have largely disappeared. Our own measurements with the Dark Decay Assay show that the Poor Knights are in two kinds of water, one with reasonable health and the other with high bacterial attack and ill health, and that the quality of the water improves with depth. In other words, degradation is particularly strong in the shallows. It seems as if the food chain is not working, food heaping up in the form of invisible tiny gelatinous plankton that concentrates near the surface, where it rots away with high concentrations of bacteria. But degradation is more sneaky than that.
 

f045231: a graveyard of purple jellyfish normally found in cooler waters.

f012425: the X-wing gooseberry looks like a normal sea gooseberry when it furls its wings, see below.

f038718: a large salp (Pyrostremma spinosum) stranded in the kelp forest. It is shaped like a rigid long sock consisting of 1cm long animals pumping water from the outside in, while sieving it for food.

f028008: rosettes of pelagic seasquirts, all joined together. As the seasquirts pump water through their bodies, the chain is propelled. Previously common, now rare.

f038635: an X-wing sea gooseberry with its wings furled (rolled up). These comb-jellies are very complex with their wings and spiralling whips.

We discovered  that the planktonic bacteria are of decisive influence on the health of all marine organisms, some species more than others. Increase the amount of food by raising the nutrients, and instead of it benefiting the food chain from zoo plankton to fish, it benefits the decomposing bacteria who then kill the zoo plankton and food chain. The big change happens at about 15m visibility, and this is precisely the barrier that the Poor Knights have been breaking in recent years. For instance, in all of our measurements in 2006, visibility was never better than 18m, and often less than 6m.

Another overwhelming but not quite obvious indicator of the loss of fish and them not reaching old age, are the demoiselles. Their numbers are way down compared to the sixties and seventies, but so is their age. Old demoiselles of over 5 years, are deep blue with bright white tails, whereas the younger ones tend to be greenish-blue or bluish with pale spots. Another indicator is that few of them breed, and many of the rocks once covered in breeding male demoiselles, now lie barren or are overgrown with weeds. In the good days there were so many males that each did not have more territory than a spread hand. Now their territories are 4-6 times larger. The same counts for the black angelfish.
 

f019816: a mature 5-7 year old male demoiselle (Chromis dispilus)  is almost deep blue (chromis=blue) with a white tail, but not quite like it used to be. These can no longer be found on the Poor Knights.

f032712: the male demoiselles now found at the Poor Knights, although mature, are no older than 4 years, and their colour has not deepened to blue, and neither have their tails become white.

Indicators of loss of life are not necessarily expressed in numbers and sizes. A very sneaky indicator is that the female green wrasses have disappeared but not the males. This is because all females eventually become male and if there is no offspring, one ends up with males only and the end of reproduction. At the moment most wrasses are in some way affected, although their females have not altogether disappeared.
 

f012604: a female green wrasse is green-brownish with longitudinal stripes above and a large scale pattern underneath. She does not have white fins. This one is already on her way to become male.

f020611: the male green wrasse (Notolabrus inscriptus) honours its name with a scale pattern as if inscribed. It is blue-green with white fins. It is a sturdy and big wrasse living in exposed shallows, while patrolling a large territory.

When something happens in cycles, scientists automatically conclude that it must be natural, but there is no proof for this. Nature has its cycles, but such cycles can synchronise unnatural events such as harmful plankton blooms. Harmful plankton blooms (HABs) are now reasonably well understood, in the sense that mysteriously, some naturally rare species become abundant, and when they are poisonous, can cause mass die-offs. Dinoflagellates (horrible flagellates) are some of the most harmful ones. But the guild of ordinary planktonic decomposing bacteria, has completely been overlooked, and their numbers are steadily increasing as the land erodes faster and faster, while more and more fertiliser is used, and the human population with its livestock, is expanding.

It still remains a mystery why the Poor Knights, located at the edge of the continental shelf, and well away from the degrading influences of Auckland and Whangarei, is so threatened. It makes even less sense considering the fact that Northland is so small with so few people and livestock, while also the big rivers all flow to the west coast. Add to that the East Auckland Current, an offshoot of the East Australian Current, and the mystery is complete.

But our measurements show that the filthy water from the Waikato and Auckland's sewage, plus the Kaipara, all flow northward, around North Cape and back, lining the East Auckland Current on the land side, and flowing undiminishedly to the Poor Knights. So, in the end, it is likely that Auckland and the Waikato are threatening the Poor Knights! A marine reserve cannot stop this. We have to be smarter.

Snapper counts inside the Poor Knights marine reserve (solid circles), the Mokohinau Islands (solid triangles) and Cape Brett (open squares). On left with the Baited Underwater (BUV) Video and on right through Visual Underwater Census (VUC). The right-hand graph was obtained by us from DOC and does not appear in the report DSIS142. The red average curves were drawn by us.

This study gives a good insight in how poorly scientists conduct their experiments. For instance, it was done as a before-and-after experiment where changes are explained as having been caused by the in-between (full protection). Immediately snapper numbers rose from 1 to 9 in the BUV, heralding an outstanding success of marine protection. Then somebody cautioned that they better include similar areas by way of control, and one year later, at the third data point, Mokohinau Islands and Cape Brett were taken in consideration. The study was continued for four full years, showing that snapper had increased by similar numbers in all three places. But DOC was foolish enough to claim that snapper had increased 16-fold, comparing the highest point after, with the lowest point before closure. It would have been more prudent to draw the red average curves, because the high point before closure was missing.

But there is something fishy with all this, because snapper only were counted with the BUV, whereas all other species were counted by visual census. Furthermore we have deep misgivings about the BUV because it does not satisfy the primary requirement of a measuring technique: not to influence the quantity measured. To the contrary, the BUV feeds snapper with pilchards, and then counts the maximum number of snapper in any one frame. It is a method designed to maximise its outcome. So we requested the visual census data, because from the report we knew that this had been done too. It is shown on right. As you can see, its result is as inconclusive but showing more fluctuation. Apparently snapper arrive in summer from somewhere outside the reserve, while only few stay in winter. The same for Mokohinau and Cape Brett. Thus most snapper are migratory and therefore not protected by the reserve. However, divers notice that there are more big snapper around, as can be expected. But what is the story with the other species?

After the BUV survey continued into 2009 [2], the following became evident:

• The big snapper that arrived in 1998-2000, came from outside the Poor Knights.
• The large snapper dominate, particularly in summer, but they vanish again in winter.
• Small snapper belong to the coast where they are hatched, and only after reaching a certain size can they migrate offshore.
• Snapper numbers appear to have stabilised.
• It cannot be shown that the marine reserve was the cause of the increase in big snapper, although those who stay, can grow bigger.
• It is not known whether the big snapper remain inside the marine reserve during winter. If they don't, they won't be protected.
• Marine habitats did not change due to the presence of big snapper. Sea urchins did not increase or decrease in numbers, neither did seaweeds. [3]

From the DSIS142 report we took the counts for those fish that belong to the Poor Knights thus not the overstayers that come during some years and disappear otherwise. Their results are summarised in the diagram on right. What does it tell us? Fish have been counted by swimming along a transect line and covering 125m2 each time, about the size of a tennis court. Look at the red pigfish (orange curve) and you see that in 1998 about one pigfish could be found in an area the size of a tennis court. Four years later it took two tennis courts to find one. As you can see, the story is quite similar for the other species, but quite disastrous for butterfish, banded wrasse and leatherjacket who declined 10-15 fold. The decline cannot be explained from a lack of food as for all, plenty of food is available.

One sad thing about all this work is that somebody decided not to census the pelagic fish like blue maomao, trevally, demoiselle, koheru and jackmackerel. We queried DOC about this, and the answer was that fish schools are too variable and difficult to count (Oops!). Then again, they did count sweep, which is a schooling fish. What is so sad about this decision is that the scientists entirely missed the mass mortality event of 2000-2001. But what did emerge is that sweep, a coastal fish that does not belong to the Poor Knights, made a spectacular debut, from zero to 3, becoming more numerous than any of the others shown in the graph. Indirectly this implies that the water quality of the poor Knights has degraded to a level less suitable for blue maomao but more suitable for sweep.

The big message for the public is that even our best marine reserve does not protect marine life in the presence of degradation, and that the situation with all our other coastal marine reserves is far worse. Yet this government is pushing for more marine reserves, for the sole reason that it signed a biodiversity consensus convention. Read the supporting chapters to understand what is happening.

[1] Denny, C, Willis, T J and Babcock, R C (2002): Effects of Poor Knights Islands marine reserve on demersal fish populations. 57p. Report to the Department of Conservation. DSIS142. www.doc.govt.nz/upload/documents/science-and-technical/dsis142.pdf
[2] Paul Roux De Buisson (2009):  Poor Knights Islands Marine Reserve and Mimiwhangata Marine Park fish monitoring 2009  (PDF) DoC report
[3] Shears, Nick T (2007): Shallow subtidal reef communities at the Poor Knights Islands Marine Reserve after eight years of no-take protection.  (PDF) DoC report.