Degradation examples - Part 2
by Dr J Floor Anthoni (2004)

The second 50 visual examples of degradation, beginning with various aspects of plankton blooms

For comments, corrections or suggestins, please e-mail the author Dr Floor Anthoni.
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the sea at Goat Island looks often like this
f212406: the sea in the Goat Island marine reserve now often looks like this, with mud soiling the water and threatening sea life. But once the mud has been cleared away, its nutrients fertilise the sea, resulting in dense plankton blooms which also threaten for a long time afterwards. Goat Island 1999.
possums killed trees at Cape Brett
f014321: all the coastal trees have been killed by the possum, introduced from Australia. Once the roots let go, the soil slips into the sea and it won't take long before the whole coast reverts to barren rock. In 20 years from now, people won't even remember what it once looked like. This land is managed by DoC. Cape Brett 1997.
a mixed school of kahawai and trevally frothing the water
f011204: a mixed school of trevally and kahawai is frothing the water, with birds working from above. This used to be very common with schools up to one hectare in size, counting tens of thousands of individuals. Now it has become a rare sight, as schools are also much smaller. Cape Brett 1996.
trevally and blue maomao feeding
f990208: a small school of young trevally and blue maomao (4 years old) feeding on the surface, pushing their backs out of the water while swimming furiously. Such schools disappeared in 1992 and again in 2001. Poor Knights 1999.
red tide plankton bloom
f942018: left image of a panorama showing a red tide of the plankton dinoflagellate Noctiluca scintilans or sea spark. Sea spark is common around our coasts, all year long, as it is easy to see during night dives. Leigh.
red tide plankton bloom
f942019: the righthand image of a panorama. Usually in the warm months of February to April, one would see some of these red tides. But they have become more common and more intensive lately, also appearing throughout the year.
view of a red tide
f942017: red tides are the most spectacular of plankton blooms because they also give light at night. But they are not poisonous and seldom kill fish. Leigh 1994.
red tide seen from underneath
f002306: as this underwater photo shows, the sea spark dinoflagellates which can swim, concentrate at the surface in a wind-blown thin layer. These tiny plants consist of jelly. Goat Island.
very large jellyfish
f003724: during periods of red tides, jellyfish like this blue jelly Cyanea lamarcki can become really big. The photo shows one measuring one metre across. As the dark eggmass underneath fills a whole bucket, they can breed a plague. Goat Island 1995.
jellyfish scyphistoma polyps under an overhang
f033522: jellyfish scyphistoma polyps have attached to a bare rock under an overhang. Each polyp can produce up to one hundred new jellyfish, so this patch alone can spawn a whole jellyfish plague. When bare rock becomes available due to sponges dying earlier on, jellyfish can indeed proliferate profusely. It is a powerful indicator of degradation. Leigh 2003 .
sharp boundary of brown bloom
f011134: phytoplankton can grow very fast, often in patches with sharp boundaries. Here is a brown bloom rapidly growing into the still clear green water. Mimiwhangata Hr.
a deep red plankton bloom
f011118: a deep red plankton bloom that could well be poisonous. Such patches are good indicators of impending decay. Bay of Islands Dec 1996.
a thick brown plankton slick
f970421: the plankton blooms so thick that it looks like an oil spill, threatening the toheroa clams in the beach. This is a sure sign of eutrophication. Westcoast off Dargaville 1997.
health warnings are good indicators
f202317: for those who do not dive, health warnings like these are sure signs of degradation. Keep an eye out for them. Kaipara Hr.
pilchard mass mortality
f002004: a mass mortality of pilchard (Sardinops neopilchardus) happened in July 1995 over a large area, outside the Hauraki Gulf. Wind-blown to the shore, fish beached like this. Leigh.
pilchard death in Leigh Harbour
f001727: what remained of the pilchard washup the day before. These fish disappeared in two days. Remember that most dead fish sink while no more than 5-10% float. So what washes up on beaches is but a small part of the whole disaster. Leigh Harbour, Jul 1995.
parore bite marks on bare rock
f991027: these are scrape marks of parore (see right), cleaning the rocks from detritus rich in diatoms. Remarkable is that underneath the dust one does not find pink paint but only bare rock, an indication of severe degradation. Long Bay 1999.
parore (Girella tricuspidata)
f017816: parore (Girella tricuspidata) is an important reef fish, because it cleans plants and rocks from invasive algae. Many have been lost from Goat Island due to a disease and degradation. Many of these fish were seen with white welts on their bodies.
blue penguin deaths
f990833: in a small area of the beach, these dead blue penguins (Eudyptula minor) were found. Whangapoua Beach, Coromandel 1999.
mass mortality of blue penguin
peng09: a mass mortality occurred at Goat Island. These birds washed up after a beach cleanup the day before. since this event, penguin numbers have been declining sharply, as also the breeding colonies of gulls and terns on Goat Island disappeared. Goat Island.
a thick wash-up of parchment tube worms
f211016: a dense bed of empty parchment tubes washed up to become a nuisance to bathers. Long Bay 2001.
closeup of dead parchment worms
f211017: closeup of the mess of empty parchment tubes. Long Bay beach and marine reserve.
a densely packed cake of parchment tubeworms
f021017: underwater, parchment worms can be very effective at converting a sandy habitat to a thick cake of cemented tubeworms. What they need is a thin layer of mud to start them off on the sand. Leigh 1999.
parchment worm exposed
f025805: a parchment worm (Chaetopterus variopedatus) was carefully peeled out of its tube and photographed under water. It is a complicated bristleworm. Leigh 2000.
smothered seaweeds and strange sponges
f035907: smothered flexible weed (Carpophyllum flexuosum) and strange dark purple finger sponges and massive sponges. Port Fitzroy, Gt Barrier I 2003.
In the most degraded of all habitats, one often sees strange sponges, as if these do not belong in New Zealand.
undaria seaweed is introduced
In colder waters, the undaria seaweed is spreading. Such propagation success may be related to degradation as space becomes available to settle on. Undaria pinatifolia is, like garden weeds, an annual plant, dying at the end of one year  and sprouting again from its offspring. Wellington 2003. Photo Rob Marshall.
a dead atrina bed
f005121: a bed of large atrina fan mussels trap mud in between them while providing an artificial substrate for filterfeeders like these short-lived soft corals (Alcyonium sp.). There is only one year class and they are all dead, a sure sign that this is the end of it. Mouth of the Mahurangi Harbour 1995.
paua in a degraded habitat
f026711: Five large paua on this picture, yet the rocks remain poorly grazed. The paua are all of same age and none is growing well as shown by their growth margins. Nowhere can juveniles or other year classes be found. This is certain degradation and spells the end of paua. Flea Bay marine reserve near Christchurch 2000.
sea cucumber cleaning golden golfball sponges
f017315: a trove of golden golfball sponges (Tethyia aurantium) is being cleaned by a single sea cucumber (Stichopus mollis)  (1998) However, in 2002 these rocks proved to be barren. The end of a habitat. Near Martins Bay, Hauraki Gulf.
a sea cucumber cleaning various sponges
f017316: two sea cucmbers are cleaning a boring sponge (Clione celata) while other sponges await their turn: the red meatball sponge (Aaptos aaptos) and yellow nipple sponge (Polymastia croceus). Years ago one could rely on sea cucumbers not being harvested, but they now fill an Asian need. Near Martins Bay, Hauraki Gulf.
sea cucumber Stichopus mollis
f017305: a sea cucumber on a very dirty patch. Martins Bay. Depositon and algal growth of this magnitude is almost always fatal.
rotting kelp holdfast
f042007: once its stipe has gone, a kelp plant dies back completely while rotting away. The last bits to go are its holdfast of spreading 'roots', which take 6 months before disappearing. After that, there still remain the white imprints on the pink paint below.
infested stalked kelp
f033509: this stalked kelp (Ecklonia radiata) has lost its self defence, allowing grey mats of bryozoa and other infestations to cover it all over. From this kind of infestation it will not recover. In the background the whole kelp forest looks similar. Leigh Jan 2003.
the kelp's lower boundary moving upward
f042706: the kelp forest's lower boundary is dying while juveniles are absent or insufficient. It means that the lower boundary is shifting upward as the water has become dirtier, a sure sign of degradation. Poor Knights 2004.
lower kelp boundary thinning
f017115: The kelp is dying back as no recruits are present. Also only the most hardy of sponges are found underneath, as the others have died. One of the most beautiful reefs, Floor's Reef in the Goat Island marine reserve has become a shadow of its former glory. Goat Island marine reserve 1998.
dying kelp forest
f033816: the old kelp is dying from lack of light and the young kelp is too sparse to replace it. At the same time coralline algae take over on the rocks. There are no sponges or filterfeeders or grazers below. This will become barren rock. Flat Island Kawau I 2003.
sand dahlia anemones have become rare
f003713: sand dahlia anemones can grow larger than a hand in various beautiful colours. They survive the wave-washed sand which also keeps them clean. But they are disappearing, as also they are becoming smaller. Near Goat Island 1995.
beautiful sand dahlias Isocradactis magna
f003710: beautiful sand dahlias (Isocradactis magna) tucked safely in between the cracks of solid rock. Hardy to sand blasting, these anemones are sensitive to degradation. Near Goat Island.
lamp shells Brachiopods
f036114: Brachiopod lamp shells on a rocky wall are a sign of health, particularly when several year classes can be distinguished as on this photo. Whangamumu Hr near Cape Brett.
dead brachiopod lamp shells
f025912: dead Brachiopod lamp shells on a vertical wall. In the Goat Island marine reserve nearly every vertical wall that is turned away from the light, used to be covered in these but they have all disappeared. Notice the very few small red lampshells. Near Leigh 2000.
a dense mat of life
f029923: underneath the kelp forest one should find a dense mat of life, particularly near currents, as shown here. On closer inspection, all animals shown here are short-lived, a sign of alarm. However, elsewhere the situation is far worse as competition for space has ended, even though more planktonic food is available. Poor Knights marine reserve.
left-over species on a vertical wall
f030216: on this vertical wall one finds sessile filterfeeders. They are all short-lived, and competition for space is rather weak, showing much empty territory. Yet there is ample food for all and also shelter. Brachiopod lamp shells used to live here. Goat Island marine reserve 2002.
mushroom compound seasquirts
f030218 orange compound mushroom seasquirts conquering space underneath an ailing kelp canopy. There is much sediment and little competition. Goat Island marine reserve.
a sandy flat with sponges
f033409: various species of sponge occupy a sandy flat under the kelp forest, where also goatfish sleep. It would be a sign of health but no sponge is older than 3 years, perhaps due to a recent disaster. Tawharanui marine reserve, 2003
garden of sponges on a rock
f036608: this rock is covered in sponges whereas the area around is not, because it juts out in the current and above the sand. Yet competition for space is not fierce. Some sponges are older than 10 years, a good sign. Left-over species. Near Leigh.
carpet fan worms
f041036: these carpet fanworms have become rare, as they disappeared from 5 of 6 places I knew. But here they thrive in a degrading harbour because dredging for scallops has diminished as few scallops are left. Whangaroa Hr 2004.
nipple sponge stifling its nipples
f022901: a diver shows how an orange nipple sponge (Polymastia granulosa) withdraws its nipples when touched. It also does this when 'unhappy', a sign of stress. These large sponges were once common everywhere down from 6m depth. They even occurred in the Channel and around Shag Rock, together with the yellow nipple sponge Polymastia croceus which prefers deeper water. Goat Island marine reserve 2002.
unhappy orange nipple sponge
f036017: this orange nipple sponge was able to grow large because it had no competition for space. But it has withdrawn its nipples as a sign of stress. This is the urchin barren zone, but urchins have left. One dead urchin below. Mimiwhangata marine park 2003.
dense carpet of life
f040629: on a pinnacle, exposed to the sea, one finds this dense mat of life as jewel anemones in all colours conquer space from a sick boring sponge. Good and bad signs. Cavalli Islands Truelove Reef.
leftover species
f036018: dense life and fierce competition with few old species (stick bryozoa, still looking sick) but these are the leftover species, found only in the most favourable places. It shows what once lived everywhere, a confirmation of degradation. Mimiwhangata marine park 2003.