UNDERWATER LIFE OF THE HAURAKI GULF This poster celebrates the diversity of marine species found in the Hauraki Gulf Marine Park.

Kingfish Seriola lalandi Haku

100-200cm

5 6 7

8

9 10

1

3

4

2

Kingfish

Hapuku Polyprion oxygeneios

60-200cm

Bluenose Hyperoglyphe antarctica Matiri

60-140cm

PROTOCTISTA:Foraminifera

Globorotalia inflata

Crayfish or rock lobster Jasus edwardsii Koura

Kina Evechinus chloroticus

Common kelp Ecklonia radiata

PHYTOPLANKTON: 5. Diatom Chaetoceros decipiens 6. Dinoflagellate Gymnodinium simplex 7. Coccolithophore Emiliania huxleyi 8. Dinoflagellate Ceratium fusus 9. Diatom Pseudo-nitzschia australis

10. Diatom Guinardia delicatula

ZOOPLANKTON: 1. Copepod Calanus australis 2. Ctenophore (comb jelly) Pleurobranchia pileus 3. Salp Thalia democratica 4. Euphausiid (krill) Nyctiphanes australis

Bryde’s whale Balaenoptera edeni

11.5-14.5m

Orca Orcinus orca Maki

5.5-9.8m

Common dolphin Delphinus delphis Aihe

1.7-2.7m

Bottlenose dolphin Tursiops truncatus Terehu

1.9-3.9m

Pilot whale Globicephalus macrorhynchus Upokohue

3.8-6m

New Zealand fur seal Arctocephalus forsteri Kekeno

male: 2.5m | female: 1.5m

Flying fish Cheilopogon pinnatibarbatus

25-45cm

Blue shark Prionace glauca Mango-pounamu

up to ≈ 4.3m

Skipjack tuna Katsuwonus pelamis Aku

45-100cm

Kahawai Arripis trutta

40-60cm

Trevally Pseudocaranx georgianus Araara

30-60cm

Manta ray Manta birostris

Eagle ray Myliobatis tenuicaudatus Whai repo

60cm-1.5m (across wings)

Sunfish Mola mola80-150cm

Snapper Pagrus auratus Tamure

30-80cm

John Dory Zeus faber Kuparu

30-40cm

Sandager’s wrasse Coris sandeyeri

20-45cm

Australasian gannet Morus serrator Takapu

89cm

Fluttering shearwaterPuffinus gavia Pataka

33cm

Hammerhead shark Sphyrna zygaena Mango-opare

up to ≈ 3.5m

Blue maomao Scorpis violaceus Maomao

20-40cm

WILDLIFE OF THE HAURAKI GULF MARINE PARK

(female)

(male)

Pilchard Sardinops neopilchardus Mohimohi

10-25cm

Red moki Cheilodactylus spectabilis Nanua

40-60cm

MARINE BOUNTY

Project director: Tim Higham, Manager, Hauraki Gulf ForumProject co-ordinator: Chris Gaskin, Kiwi Wildlife/Natural Lines ConsultancyDesign: Kylie Hibbert, The New Zealand HeraldWildlife artist: Vivian WardText: Karen TricklebankContributors: Simon Franicevic, Roger Grace, Tim Lovegrove, Tom Trnski,

Hugh Grenfell (Geomarine Research), Janet Bradford-Grieve (NIWA), The School of Biological Sciences The University of Auckland (Kendall Clements, Rochelle Constantine, Mazdak Radjainia, Iain MacDonald), staff of Auckland Council and Department of Conservation Related websites: www.haurakigulfnz.com; www.haurakigulfforum.org.nz; www.haurakigulfmarinepark.co.nz

CREDITSPRODUCED BY IN ASSOCIATION WITH SPONSORED BY

The Hauraki Gulf Marine Park was established in 2000 under the Hauraki Gulf Marine Park Act. As our first national park of the sea, made up of 1.2 million hectares of water and more than 30 major island groups, it protects scenery, ecosystems and natural features that are nationally significant for their beauty, uniqueness and scientific value.

Photo © Tony and Jenny Enderby

Bryde’s whales reach up to 14.5 metres in length and 40 tonnes in weight. They are unique among baleen (filter-feeding) whales as they do not appear to migrate to feeding grounds in the Southern Ocean each summer and are thought to remain in waters warmer than 15-20˚C. The resident population in the Hauraki Gulf is estimated to number between 100-200. Calves are often seen, suggesting the species is breeding here.

Long Bay – Okura

HAURAKIGULF

Te Whanganui – A – Hei(Cathedral Cove)

Tawharanui

Cape Rodney – Okakari Point

Motu Manawa – Pollen Island

Safe havens

Photo © Tony and Jenny Enderby

Blue maomao

Boundary of Hauraki Gulf Marine Park

Photo © Tony and Jenny Enderby

Sponge habitat

Photo © Rochelle Constantine

Close to home: Bryde’s whale

Marine reserves in the Gulf

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SUPPORTED BY

The sea boiled with kahawai and trevally over several acres, screaming terns and gannets diving from above.

Surface trevally rushed forward noisily, gorging themselves on tiny krill. Into the surging sea surrounded by swarms of

silver bubbles, we powered down below the unsettled surface.Down past dark glistening bodies of frantic kahawai.

Down through plankton-feeding demoiselle and bright blue maomao. Down past crowds of pink maomao, their

colour faded whitish blue in the deepening light. Down the bottomless vertical wall. Sentinel kingfish cruised the void. Ghostly white hydroid fans punctuated the dark rock face.Suddenly, staring with large saucer-eyes, was a huge groper like a small cow. With two audible thwacks of his powerful tail, he dissolved into the inky depths. Nitrogen narcosis was

kicking in. Time to get out of there.¹

Auckland’s own whale

Right on the city’s doorstep, a group of little known Bryde’s whales makes the Hauraki Gulf their home. A member of the pod divides the waters of the Hauraki Gulf as it surfaces for air. Feeding on enormous quantities of plankton and small baitfish such as pilchards and anchovies, these large baleen whales are a sign of the abundance of life in the gulf. Sometimes the whales’ huge flukes – extending out of the water as they lunge forward on their sides in open-mouthed feeding manoeuvres – can be mistaken for the enormous dorsal fins of orcas.

The schools of silvery fish moving together in a dance of swirling shapes quickly become the prey of larger creatures in a

feeding frenzy known in fishing circles as a ‘boil-up’ or ‘meatball’. The ocean seethes with life as a multi-pronged attack is launched: the fish are trapped near the surface by large predators such as kingfish and common dolphins herding them from below, while avian predators such as gannets and shearwaters dive down from above and pursue them underwater.

Power supply

Surprisingly, the powerhouse driving this melee is made up of millions of microscopic phytoplankton – single-celled algae. Using the sun’s rays to produce energy, phytoplankton provide food for animal plankton, known as zooplankton. Some of these minute animals will spend their whole lives floating in the plankton. Others are the juvenile forms of more familiar marine animals such as crabs, shellfish, fish and sea urchins destined to escape to a new lifestyle if not eaten first.

As daylight lengthens, the warming waters combine with an influx of nutrients from deeper waters and trigger a sudden increase, or ‘bloom’, in phytoplankton numbers. Blooms bring about changes to the water’s clarity, giving it a ‘greenish’ appearance. Their timing is part of an annual cycle, feeding the tiny larvae of many marine organisms over spring and summer.

Wall of mouths

Millions of reef-encrusting animals feed on the plankton soup that swirls around them. Colourful sponges and colonial sea

squirts are among the creatures that live permanently attached to rock surfaces, competing for space as tiny particles of planktonic food drift past them in the currents. The flow of plankton is simultaneously devoured by hungry fish such as blue maomao, trevally and demoiselles. At dusk the nightshift plankton feeders such as bigeyes take over while the day feeders go to sleep.

Larger algae or seaweeds are a food source for herbivorous or grazing fish such as butterfish, marblefish and silver drummer, which have specialised ways of digesting the chemicals that the seaweeds contain. Spotties and other wrasses meanwhile feed on the tiny snails and crustaceans that graze on the algal ‘fuzz’ that grows on the surface of seaweeds. Kina (sea urchins) use their five-toothed jaws to graze algal mats directly from the surface of rocks. Groups of kina can form a formidable army, which can literally mow down areas of the common kelp, Ecklonia radiata, leaving a bare rock surface (‘kina barrens’) much like clear-felled forests on land.

Top of the chain

Snapper consume a wide variety of foods found on rocky reefs, switching prey as they grow. Armed with sharp teeth the larger snapper are able to tackle heavily armoured shellfish and can even crack open prickly kina. The large-lipped, but toothless red moki suck in seemingly indigestible coralline algae, extracting the tiny animals that live among them and expelling indigestible particles through their gills. Crayfish emerge from their lairs at night roaming widely to hunt shellfish, crabs, starfish and kina. Among the top predators in the Hauraki Gulf are dolphins such as bottlenose and common dolphins, which move through the

waters feeding on kahawai, sprats and other large fish. Meanwhile, powerful orca come in close to shore to feed on stingrays.

Taking care

Humans are also top predators, using commercial and recreational means to target their most favoured species from Gulf waters. As a result, the numbers of many popular edible species like snapper, kahawai and kingfish have declined to a fraction of what they once were. Some, like hapuku or groper, were once the top predator of inshore reefs, but are now considered a deeper water species. Entire habitats, such as the mussel beds that once stretched from Waiheke Island to the Firth of Thames, have disappeared. Other human activities that have a major impact on the marine environment include sand dredging by the construction industry, dumping of harbour dredgings, urban development, farming and forestry. Run-off from the shore, especially during heavy rains, regularly sends plumes of brown sediment into the Gulf ’s estuaries and open waters, smothering delicate filter-feeding animals and blocking out sunlight that is so crucial to the health of seaweeds. Chemical pollutants from myriad sources can bind to sediments and enter the ocean through our waterways, often with unknown consequences to marine life and to ourselves.

The sea is an important part of our lives. It provides us with kai moana, inspiration, ancestral connections and valued recreational and economic opportunities. Managing our extraction of its precious resources, and reducing the contaminants we release into it, is critical to the well being of the life it supports.

¹ Roger Grace’s dive log, 1969.

Diver and snapper. It is estimated fishing has depleted snapper populations by more than 80% in the Hauraki Gulf. Densities of harvestable size snapper are around 14 times higher in marine reserves than surrounding fished areas.

Within the Gulf there are currently five small marine reserves which protect less than 0.3 per cent of the Gulf’s marine area. As well as being small, these areas are not representative of the Gulf’s range of habitats and species with, for example, only an estimated 37 per cent of intertidal species present within the Gulf currently protected. They also do not form an effective network.

Cape Rodney-Okakari Point became New Zealand’s first marine reserve in 1975. Within ten years snapper and crayfish populations re-established, previously decimated by overfishing, setting off a series of changes in the ecosystem of the reserve. Nowhere else on the coast teems with such a profusion of fish life that can easily be seen by visitors. The marine reserve has returned to what we imagine it would have been like prior to the arrival of humans.