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Marine conservation

by  Gerard Hutching and Carl Walrond

Surrounded by a seemingly limitless and abundant ocean, New Zealanders for years plundered its riches with no thought for tomorrow. It was not until the 1970s that people acknowledged the fragility of the marine environment and its fish, birds and mammals. Since then, laws have brought greater protection, and the establishment of marine reserves and sanctuaries.

Māori and the sea

A limitless supply?

When the first humans arrived in New Zealand from Polynesia, probably about 1250–1300 CE, they found food in abundance around the coast. As well as moa and other land birds, the coastline offered seals, sea lions, shellfish and tītī (muttonbirds), and there were plenty of fish in the sea. Dolphins and pilot whales were harpooned when they ventured close to the shore.

Archaeological evidence indicates that within 100–150 years many coastal and marine food sources had been depleted. Seal rookeries became deserted except on remote rocky coasts, and sea lions disappeared. Coastal fisheries were locally affected. For example, the oldest archaeological sites on D’Urville Island in Cook Strait contain abundant snapper bones, but these are largely absent from later sites. The resulting food shortages led to the development of resource conservation, combining a hard-headed quest for survival with a spiritual attitude towards harvest from the sea.

Tāne and Tangaroa’s children

Māori regarded themselves as people of the land – the children of Tāne, god of the forest. The marine realm belonged to the god Tangaroa, whose offspring were the fish. Tangaroa needed to be appeased through karakia (incantations) because taking fish was seen as an attack on the children of Tangaroa.

Māori and the marine environment

In the first few centuries of Polynesian arrival it was the seal and sea lion populations which suffered most. There were also considerable fish catches in some areas. As canoes mainly fished close to the coast, the impact was on inshore finned fish, and shellfish gathered from shore. Although some species were locally reduced, it is unlikely that fishing affected breeding stocks.

The Māori relationship with the sea had many practical elements, especially rāhui (bans), which restricted the harvest of fish species at certain times, and sometimes included size limits. There were tapu (restrictions) relating to certain practices such as polluting fishing areas with human waste, and rules preventing damage to fishing grounds with nets and lines. Sacks and baskets were never dragged over shellfish beds.

At the time of James Cook’s first visit in 1769, marine life seemed abundant. The reports from his expedition attracted sealers keen to exploit the bounty of the southern seas.

The boundless ocean

The history of marine conservation is essentially a record of slowly changing attitudes. In the 1800s and most of the 1900s the sea was viewed as boundless and resilient. You could take what you wanted from it and dump what you did not want into it – and it would always recover.

The environmental movement

As the environmental movement grew during the 1960s, people began to realise that the oceans were vulnerable. Continuing into the 1970s the French television show The undersea world of Jacques Cousteau revealed life under the ocean to millions. Images taken during dives from the renowned oceanographer’s research ship Calypso helped to change views worldwide.

In New Zealand, scuba-diving technology allowed a growing group of Kiwis to explore beneath the waves. Marine scientists and divers, including Bill Ballantine, Wade Doak and Kelly Tarlton, also began to lobby for protection of the sea and its varied life forms. But until the 1970s, for most New Zealanders the sea was simply a place where they caught fish, and – although they may not have considered it – where a lot of their waste ended up. These attitudes were very slow to change. While the routine dumping of all types of rubbish at sea declined by the 2000s, many people still have no qualms about tossing rubbish from their boats. Each year tonnes of marine debris, much of it plastic, fetches up on New Zealand beaches.

Pollution from the land

While some of this debris comes from vessels, the majority originates on land. Traditionally there was little recognition that activities on land could affect the marine environment, especially the coast, and yet they are among the greatest threats. One step to reverse the trend since the 1990s has been the improvement in the quality of discharges into the sea from sewer outfalls. Māori and many other people in coastal communities throughout New Zealand had long opposed the pumping of raw sewage into the ocean.

Since 1996 the fishing industry has been required by legislation to consider the ecological effects of fishing, and has come under pressure from conservationists to stop destructive fishing techniques such as bottom trawling. If the 20th century was a conservation battle on land, the ocean is a major focus for conservationists in the 21st century.

Marine mammals

Whales and seals

Europeans and Māori plundered the ocean around New Zealand, hunting seals and whales in massive numbers. By the 1830s extinction was looming for seals, and it was becoming uneconomic to send out gangs of sealers from Australia, Britain and other countries.

Concern about plummeting seal numbers resulted in a law in 1875, which banned sealing between 1 October and 1 June. After 1894 even this open season was closed except in 1914 and 1915, when hunting was allowed with a licence.

Open seasons were again allowed in 1924 and 1926 on Campbell Island, and in 1946 in Otago, Southland and Fiordland. Protection in these cases was lifted as fishers argued that seals were taking too many fish. During the last open season in 1946, 6,187 seals were killed from June to September.

Seals and sea lions are protected under the Marine Mammals Protection Act 1978. In 2003 a 12-mile marine reserve was established around the Auckland Islands to safeguard the sea lion from squid nets.

Accidental slaughter

Even though they are totally protected by law, seals and sea lions die in large numbers each year when they are caught in commercial fishing nets. Between 1988 and 2003, 7,759 seals died in hoki fisheries, and at least 2,000 New Zealand sea lions have been killed in the Auckland Islands squid fishery since 1980.

The Fishing Industry Association has produced a code of conduct to minimise seal deaths. Even so, they still occur. In 1991 the government set an upper annual limit of 65 sea lion deaths resulting from squid fishing; if this was exceeded then the fishery would be closed. In the early 2000s conservation groups were lobbying for zero sea lion deaths.


Despite its history of whale exploitation, New Zealand has led the way in modern whale protection. In 1946 it was a founding member of the International Whaling Commission, established to manage the world's whale resources. The last harpooning by a New Zealand vessel in New Zealand waters occurred off the Kaikōura coast in 1964. Having been a whaling nation for over 100 years, by the late 1970s the country was taking a strong stance against the industry.

In 1982 the commission voted for a moratorium on commercial whaling, and in 1994 established the Southern Ocean Whale Sanctuary. This covers over 11 million square miles of ocean, including all of New Zealand's Exclusive Economic Zone south of 40° south. Japan does not recognise this sanctuary and continues to hunt for minke whales in the Southern Ocean.

All whales within New Zealand’s 200-nautical-mile Exclusive Economic Zone are totally protected under the Marine Mammals Protection Act 1978. Under this act areas could be declared marine mammal sanctuaries. 

Whale watching, 1960s style

In the early 1960s New Zealand’s navy and air force carried out population surveys of sperm whales, and spotted them so that whalers could harpoon them. For the same purpose, the government also employed whale lookouts – pilots and navigators of the National Airways Authority, lighthouse keepers, coastal and trans-Tasman ships, and weather-station personnel on Campbell Island and the Kermadecs.


All dolphins are also totally protected in New Zealand waters by the 1978 act. Most species are maintaining their numbers, but others need further protection. In 2010–11 it was estimated that there were 48–69 Māui's dolphins over one year of age. In 2003 set-netting was banned between Kaipara Harbour and Mōkau to protect this subspecies. In 2008 the West Coast North Island Marine Mammal Sanctuary was established, and the area closed to set-netting was also extended. In 2012 an area in Taranaki from Pariokariwa Point to Hāwera was closed to commercial and recreational set-netting up to 2 nautical miles off the coast; commercial set-netting was allowed between 2 and 7 miles offshore only if an observer was on board. In 2013 the area between Pariokariwa Point  and the Waiwhakakaitio River was closed to all set-netting up to 7 nautical miles offshore.

Hector's dolphins, which are found around the South Island, have a larger population, estimated at around 7,000 in 2013. The first marine mammal sanctuary of 114,000 hectares was established off Banks Peninsula in 1988 to protect this species. In 2008 it was extended from the mouth of the Waipara River to the mouth of the Rakaia River and 12 nautical miles off the coast, an area of around 413,000 hectares. Catlins Coast, Clifford and Cloudy Bay and Te Waewae Bay marine mammal sanctuaries were set up in 2008 to protect Hector's dolphins. There are also various set-netting restrictions in place around the South Island. 

Other protected species

Under the Wildlife Act 1953 and the Marine Mammals Protection Act 1978, certain other marine species are protected irrespective of where they are found. All marine reptiles (including turtles and sea snakes), black coral and red coral are fully protected. In these cases protection is not only for the living creature, but any part of it.

Seabirds and shorebirds

First legal measures

From 1861 a series of animal protection acts were passed, with the main aim of seasonally protecting imported game birds such as pheasants. Initially few seabirds were protected. In fact the Animals Protection Act 1880 identified pied stilts, black stilts and the dotterel as ‘native game’, which could be hunted.

The 1880 act was changed many times. In 1921–22 it became the Animals Protection and Game Act, and the list of ‘animals absolutely protected’ was extended to include almost every native bird apart from a few considered to be pests (such as the shag), or game (such as the godwit). Almost all seabirds were protected, and it became an offence to kill them. Attitudes toward native wildlife were changing: the aim moved from maintaining species for hunting purposes to outright protection. Seabirds considered to be game were among the last native birds to be protected – under the Wildlife Act 1953.

Godwit hunting

British settlers brought with them the tradition of hunting animals for sport. Many native birds were classified as game and could be legally hunted. One Kaipara settler wrote of a day out on the estuary:

‘We came in full sight and range of a large flock of godwit. Up they rose to seek safety in flight, but the music of our guns rang out, feathers flew in all directions, and the dogs had their work cut out for some time’. 1

Degrees of protection

In the 2000s all seabirds except seven species were fully protected. The black-backed gull has no protection as it is deemed a nuisance by farmers. The subantarctic skua and black shag have a partially protected status: they can only be killed if they are damaging occupied land or property on occupied land. The subantarctic skua is not fully protected as Chatham Island farmers consider it a pest. Similarly acclimatisation societies (now Fish & Game New Zealand) had for decades considered shags a threat to juvenile trout, but the evidence does not support this view. Four other seabird species – the pied shag, little shag, sooty shearwater (tītī or muttonbird) and grey-faced petrel – may be hunted or killed subject to notification of the minister of conservation. The sooty shearwater and grey-faced petrel are traditionally harvested as chicks by Māori, which is why these species are also not fully protected.

Fishing and seabirds

Since the 1980s large numbers of seabirds such as albatrosses and petrels have died in longline and trawl fishing grounds, especially in the Southern Ocean where so many of these outsized birds live. Albatrosses and petrels follow fishing boats to scavenge the bait attached to hooks on longlines. If the bait sinks deep enough beneath them the birds might be safe, but some birds like the sooty shearwater can dive as deep as 67 metres. Albatrosses do not dive so deep; the light mantled sooty albatross dives to a comparatively shallow 12 metres.

Fewer pigs, more birds

One of the first official moves to save marine birds was made in 1936. At that time, wild pigs on Aorangi, one of the Poor Knights Islands, had reduced the number of Buller's shearwaters to just 100 breeding pairs. In contrast there were an estimated 500,000 birds on nearby Tawhitirahi Island. The government paid deer cullers to eradicate the pigs, and by 1981 Aorangi’s shearwater population had soared to 200,000 pairs.

Estimates by conservation organisations such as the Royal Forest and Bird Protection Society put the number of seabirds dying in New Zealand’s fishing grounds as high as 10,000 a year, a figure disputed by the fishing industry. Scientists estimated that in 2002–3 the number of deaths was 1,789. However, not all fisheries were included in the estimate, so this figure is a minimum.

New Zealand fishing companies and other interested parties have formed a group, Southern Seabird Solutions, to solve the problem of albatross and petrel deaths. They have experimented with a number of measures, among them the Brady Bird Baffler, a device attached to a fishing boat which confuses birds, keeping them off dangerous nets.

    • P. W. Barlow, Kaipara, or, experiences of a settler in north New Zealand. Christchurch: Kiwi, 1998, p. 137 (originally published 1888). › Back



New Zealand’s first fisheries legislation was applied to oyster fisheries in 1866. Protection for finned fish, such as closed seasons and limits on the mesh size of nets, was established with the Fish Protection Act 1877. These measures were eventually combined under the Fisheries Act 1908.

The aim was to manage fish and shellfish stocks for future catches, rather than to conserve species for their intrinsic value. If something made good eating but stocks were dwindling, legislation could help ensure it would be eaten in the future as well. When stocks recovered, regulations were relaxed. This was essentially the ethos of fisheries management until 1986.

The 1986 quota system

In 1986 annual quotas, or limits, were set for catches of different species. The intention was to manage fish stocks at levels that ensured there would be future harvests. Since 1986 more fish and shellfish species have been included in the quota system. For example, quotas were set for two pāua species in 1986, for the rock lobster in 1990 and for kina in 2002. The quota system still underpins New Zealand fisheries management and is highly regarded internationally.

Fisheries Act 1996

The Fisheries Act 1996 required the protection not only of fisheries, but also of dependent species, aquatic biodiversity and habitats. The act also introduced charges, such as the conservation services levy, with which the fishing industry must fund research into the impacts of fishing on protected marine wildlife.

In the early 2000s no fish species (except the spotted black groper) were protected; they could be taken as long as commercial or recreational fishers complied with fisheries regulations (such as size and daily bag limits). Commercial fishing enterprises were also required to hold a quota allowance. In general, the only places where fish cannot be taken are marine protected areas.


Some fish and shellfish in certain areas are also protected by Ministry of Fisheries bans, which allow stocks to recover from overfishing. As an example, the Wellington pāua fishery has been closed to commercial harvesting since 1974.

Safeguarding seamounts

Seamounts are undersea mountains, usually of volcanic origin. In New Zealand’s Exclusive Economic Zone there are at least 500 seamounts. Under the Fisheries Act 1996 the Ministry of Fisheries can prevent fishing in high-risk areas, where the effects of fishing are largely unknown. In 2001 it did just this, closing 19 seamounts to trawling. The shallowest of these peaks (220 metres) is known as Rumble III, an active volcano north-east of the North Island. The deepest peaks are the unnamed Seamount #140, north-west of Cape Rēinga, and Seamount #328, south-east of the Chatham Islands; both are 1,750 metres down. These were the first protected deep-water areas in New Zealand’s fishing grounds.

Environmental groups accuse the fishing industry of destroying the sea floor by bottom trawling. In this form of fishing, heavy nets with rubber wheels are dragged along the sea floor, damaging the marine life and the seabed in their path. Scientists estimate that it might take decades or even centuries for some of the cold-water corals and sponges to recover.

Reducing by-catch

Species that are accidentally killed in nets are called by-catch. Sea lions are found in squid nets, diving seabirds are taken on longline hooks, and less commonly, dolphins are caught in coastal set nets. Numerous other species also die from entanglement in nets.

Technological improvements are helping to reduce by-catch. Exclusion devices on trawl nets help to release seals, sea lions and turtles. Echo sounders can locate schools of hoki, a commercially trawled species, in mid-water so that trawlers do not have to drag the ocean floor. Net monitors tell skippers when their nets are full, so that they can haul them in before unwanted species are caught.

Fishermen must pay penalties if they catch too many individuals of a species for which they have no quota.


By international standards New Zealand’s coastal waters are relatively clean, although in areas close to larger centres they are more polluted. Little is known about the state of waters beyond the coastal zone. In 1976, local authorities were asked to subjectively rate estuaries in their areas. Of 162 estuaries rated, 38% were regarded as clean, 41% as slightly polluted, 16% as moderately polluted, and 4% as grossly polluted.

Sewage and industrial waste

In the western world the move toward sewage treatment only gained real momentum in the 1980s and 1990s. In New Zealand, as elsewhere, raw sewage was pumped into the ocean – the only human safeguard was to extend the outfall pipes some distance offshore. Signs in these areas warned people not to swim or collect shellfish.

In the mid-1990s a survey found that at least 1.3 billion litres of sewage and water-borne industrial waste were discharged into the sea around New Zealand every day. It also found that large quantities of industrial waste were discharged through sewage outfalls. And it pinpointed that some 80% of marine pollution came from land-based sources, around three-quarters of this being discharged through outfalls. Industrial wastes from wool-scouring plants and freezing works are flushed into the sea – usually via rivers. Urban storm-water run-off (including heavy metals) is another source of pollution. Urban storm-water systems also wash plastic and other debris to the coast.

Since the 1950s, when New Zealand had almost no sewage treatment systems, the country has made slow progress. The last major centres to stop dumping raw sewage into the sea were Wellington and Hutt Valley (in 1998 and 2001 respectively). This change was largely due to the introduction of the Resource Management Act 1991, which placed much tighter restrictions on discharges into the sea. It also gained momentum with the establishment of the Department of Conservation under the Conservation Act 1987. The department became responsible for conserving the coastal marine environment, and demanded higher levels of treatment for all discharges into the sea.

Plastic litter

Plastic and other litter is a potential hazard to marine animals. For example turtles, when searching for their staple food of jellyfish, occasionally ingest plastic bags by mistake and suffocate. Plastic items are considered to cause more deaths of marine animals than oil spills, heavy metals or other toxic materials. A year-long study of Auckland’s storm-water discharges found that each day 28,000 pieces of litter, much of it plastic, ended up in the Waitematā Harbour.

Pollution from farming

Agricultural run-off (mainly sediment, fertilisers and nutrients) is a major pollutant of some rivers, and to a lesser extent of estuaries and coastal waters. Sandy estuaries have been building up sediment at the rate of 3–6 millimetres a year, and muddy ones at 2–5 millimetres a year. This amounts to a total increase in the sediment layer over the past 100 years of between 20 and 60 centimetres.

Accelerated erosion affects life in the ocean by covering it in sediment. In some areas of the South Island, reef sponges, kelp forests, weed beds and fish nursery grounds have been lost because of increased sediment. Seagrasses in harbours and estuaries have also disappeared because of declining water clarity, linked to sedimentation.

Conscious of the pollution caused by dairy farms (cow numbers rose 34% between 1994 and 2002), environmentalists signed an accord with the dairy industry in 2003 to try and improve water quality by fencing and planting around rivers.

Oil spills

Most oil spills in New Zealand waters are minor, but they happen reasonably frequently. In 1996 there were 84 reports of marine spills, but it is likely that not all were reported. Only two involved more than one tonne of oil. In 2005 vessels more than 45 metres long were banned from sailing between the Poor Knights Islands and the Northland mainland. This was a pre-emptive move: the area was considered vulnerable to spills, as tankers regularly visit the nearby Marsden Point oil refinery.

Protected areas

Land reserves such as national parks have been accepted in New Zealand for well over 100 years. But it was not until the 1970s that people began to realise the importance of reserving some parts of the sea – areas from which no harvest is allowed.

Marine reserves

After many years of lobbying by scientists and divers, New Zealand’s first marine reserve was created in 1975. Formerly known as the Leigh Marine Reserve because of its proximity to the township of Leigh, its official title is the Cape Rodney–Okakari Point Marine Reserve. Today the area is a drawcard for Aucklanders, who live just 90 kilometres to the south, and around 250,000 people visit each year.

Such was the opposition to marine reserves, mainly from recreational fishermen, that only two were created between 1975 and 1990. Some commercial fishermen favour marine reserves, as they are aware that stocks have declined.

We want to make a reservation

New Zealand’s legislation for marine reserves is unique – any incorporated society can propose a marine reserve. Conservation groups such as the Royal Forest and Bird Protection Society have proposed several. In Fiordland the Federation of Commercial Fishermen nominated the northern half of Milford Sound as a marine reserve, and this was approved in 1993.

From 1990 momentum developed and reserves increased significantly. By the 2000s environmental groups and some marine scientists were lobbying for a target of 10% of New Zealand’s Exclusive Economic Zone to be held as reserves. A survey in early 2005 found that 90% of New Zealanders wanted more marine protection.

In 2015 New Zealand had 44 marine reserves covering 9.5% of its coastal waters (within 12 nautical miles of the coast). These are ‘no take’ areas, administered by the Department of Conservation. No living things can be removed, except for approved scientific purposes. People are free to swim, snorkel, dive and boat in the area.

Marine parks

There are two marine parks: Mimiwhangata (on the east coast of Northland) and Hauraki. Tawharanui, once a marine park, became a marine reserve in 2011. Each park has different regulations: Mimiwhangata principally protects reef fish, but not animals such as spiny lobster and green-lipped mussels. Fishing and shellfish gathering is allowed throughout the Hauraki Marine Park, except in the five areas (less thatn 0.3% of the park's total area) set aside as marine reserves.

Marine protected areas

In 2014 there were three marine protected areas: the Sugar Loaf Islands near New Plymouth, the Fiordland (Te Moana o Atawhenua) marine management area and the Kaikōura (Te Tai ō Marokura) marine management area. All three have marine reserves within their boundaries; a variety of fishing regulations apply to the other waters. The Kaikōura area also contains a whale sanctuary, a fur seal sanctuary, two taiapure areas and three mātaitai reserves.

Māori fisheries management

Māori notions of marine conservation are different to the preservationist, no-take approach. In recognition of this, and of Māori customary fishing rights, the Ministry of Fisheries and iwi (tribes) from around the country have worked to create reserves known as mātaitai and taiapure where fishing has traditional significance.

Taiapure are fishing areas intended to be managed by local tribes. They must be important for local Māori, and lie within traditional fishing grounds. Administrative committees recommend regulations to manage the harvest, including commercial fishing. By 2012, eight taiapure had been established.

Mātaitai are areas where local tribes manage all aspects of non-commercial fishing by making by-laws, which apply to everyone. Generally, commercial fishing is not allowed within mātaitai. By 2012, 25 mātaitai had been created, covering 32,200 hectares.

The individuals responsible for managing tribal fisheries are known as tangata kaitiaki (in the North Island or Chatham Islands) or tangata tiaki (in the South Island or Stewart Island). They act as guardians of customary fishing in their area.

Marine mammal sanctuaries

In 1988 New Zealand’s first marine mammal sanctuary was established around Banks Peninsula, as high numbers of Hector’s dolphins were being caught in set nets. This area was extended in 2008. Fishing restrictions and restrictions on seismic surveys are intended to minimise disturbance to marine mammals. A second sanctuary, established in 1993, surrounds the Auckland Islands to a distance of 12 nautical miles offshore. This protects the main breeding areas of the New Zealand sea lion and the southern right whale. It was also made a marine reserve in 2003, to protect the rich marine life. In 2008 four more marine mammal sanctuaries were established. Catlins Coast, Clifford and Cloudy Bay and Te Waewae Bay sanctuaries protect Hector's dolphins. The largest, the West Coast North Island sanctuary, was created as part of a plan to protect Hector's and Māui's dolphins. It stretches from Maunganui Bluff in Northland to Ōakura Beach in Taranaki, and covers around 1,200,086 hectares.

Hononga, rauemi nō waho

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How to cite this page: Gerard Hutching and Carl Walrond, 'Marine conservation', Te Ara - the Encyclopedia of New Zealand, (accessed 16 June 2024)

He kōrero nā Gerard Hutching and Carl Walrond, i tāngia i te 12 o Hune 2006, updated 1 o Hepetema 2015