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Our marine environment 2019

Collecting shell fish at low tide, Duders Beach, Firth of Thames. Credit: Sandii McDonald, Photo New Zealand


We would like to thank the following people and organisations for their invaluable contribution to Our marine environment 2019 and Environmental indicators Te taiao Aotearoa: Marine.

Data providers

We thank the following for providing data for this report: 

  • NIWA
  • Department of Conservation
  • Stats NZ
  • Regional Councils.

Senior Science Advisers

We thank the following people and organisations for reviewing this report:

  • Cliff Law, NIWA
  • Hilke Giles, Pisces Consulting
  • Kura Paul-Burke, NIWA.

Technical advisory group 

We are very grateful for the assistance of the technical advisory group, who provided advice on potential measures and feedback on draft versions of this report.

  • Barb Hayden, NIWA
  • Chris Cornelisen, Cawthron Institute
  • Debbie Freeman, Department of Conservation
  • Anna Madarasz-Smith, Regional Councils Coastal SIG
  • Matt Pinkerton, NIWA
  • Mary Livingston, Ministry for Primary Industries 
  • Vaughan Stagpoole, GNS Science.

We also acknowledge Stephen Hunt and Louis Tremblay who provided information for case studies.

This report was compiled by the Ministry for the Environment and Stats NZ’s marine Environmental Reporting team.

Photo credits

Cover photo:

Above and below the water at the Mokohinau Islands, Hauraki Gulf. 
Credit: Lorna Doogan, Experiencing Marine Reserves

Section photos:

Our marine environment at a glance: 
Fishing in Whangaruru, Northland. 
Credit: TS Images, Photo New Zealand

What the marine environment means to New Zealanders:
Collecting shell fish at low tide, Duders Beach, 
Firth of Thames
Credit: Sandii McDonald, Photo New Zealand

Issue 1: Our native marine species and habitats are under threat
Rich biodiversity at the Mokohinau Islands, Hauraki Gulf. 
Credit: Lorna Doogan, Experiencing Marine Reserves

Issue 2: Our activities on land are polluting our marine environment 
Stormwater pipe, Paremata Harbour. 
Credit: Rob Suisted, Naturespic

Issue 3: Our activities at sea are affecting the marine environment
Fishing vessel in the Tasman Sea. 
Credit: “Mickrick”, istock photos

Issue 4: Climate change is affecting marine ecosystems, taonga species, and us
Credit: T Whittaker

All our activities put cumulative stress on the marine environment:
Paremata Mana Plimmerton Porirua Harbour and  Kapiti Island
Credit: Colin Monteath, Alamy Australia

Towards a better understanding of our environment:
Collecting samples for ocean acidification studies along  the Munida Transect, off the coast of Otago.
Credit: Dave Allen, NIWA

Environmental reporting series and References
Northland east coast scene south of Cape Brett 
Credit: TS Images, Photo New Zealand.

Message to our readers 

Aotearoa New Zealand is an island nation, so te moana – our marine environment – is central to our identity, the activities we enjoy and our prosperity. It provides for us in so many other ways too, for example, regulating the climate and absorbing pollutants. We have one of the largest areas of ocean in the world, so how we look after it makes a difference.

This report marks the beginning of the second cycle of environmental reporting, building on previous reports including Our Marine Environment 2016 and Environment Aotearoa 2019. It shines a light on the pressures and changes in the marine environment so we are equipped to make decisions to better safeguard it into the future. 

Our marine environment 2019 examines the most pressing issues in our oceans, seas, harbours, and coastlines. Four priority marine issues have been selected for this report: biodiversity loss, activities on land, activities at sea, and climate change. Evidence supports that these are the areas most in need of attention and action for our oceans and coasts.

What this report shows is that our marine environment continues to experience pressure from the combined effects of our activities – both on land and in our oceans. In some areas, we are seeing improvements, for example, some marine species are back from near extinction and seabed trawling and dredging have decreased in the last 20 years. But in others, the data shows some of the effects are worsening, and faster than first thought. This is especially true of the impacts of climate change and pollution on our marine environment.

Some of the impacts of individual activities are obvious – the number of marine species caught as bycatch, for example – but it is the cumulative effect of many pressures that could present the biggest issues, and there is so much we still don’t know. We know less about our coasts and oceans than any other environmental domain.

However, we are building a more complete picture all the time. For the first time, we have broadened our body of evidence to include citizen science and are increasing our use of mātauranga Māori. And improved satellite monitoring, especially in near-coast areas, allows us to better understand the impacts of climate change in our oceans. 

The challenges our oceans face are complex and there are many ways we could tackle them. In some areas, positive change is already occurring. lwi, the science community, industry, coastal managers, and communities have already begun to take steps to improve the health of the marine environment. New technology offers the potential to better monitor the marine environment cost effectively and improve our understanding of, and ability to manage, cumulative pressures.

While we have expanded the range of data used in this report, it is an ongoing journey to build knowledge on what matters most for environmental outcomes in Aotearoa. We hope it provides a basis for an open and informed conversation about what we have, what we are at risk of losing, and where we can make changes.

Vicky RobertsonLiz MacPherson

Vicky Robertson                                          Liz MacPherson

Secretary for the Environment                Government Statistician

Our marine environment at a glance

Te moana, the coast and oceans of Aotearoa New Zealand, are central to our identity and intertwined with our history – we are a maritime nation. For Māori, te moana is a source of whakapapa.

We have one of the largest areas of ocean in the world. Our marine landscapes and habitats are diverse, supporting complex ecosystems and many unique species.

Our oceans support us. The marine economy added $7 billion to our economy in 2017 and employed more than 30,000 people. Healthy marine ecosystems provide essential benefits like taking up carbon dioxide, removing pollutants and providing kaimoana. In te ao Māori (the Māori world and worldview) the mauri, or life force, of a healthy moana enhances the mauri of those who interact with it. 

This report summarises four priority issues for the marine environment and these issues mirror those we are also grappling with on land. 

Our native marine species and habitats are under threat

An estimated 30 percent of Aotearoa New Zealand’s biodiversity is in the sea but many species are in trouble: very few marine species are assessed, but of these 22 percent of marine mammals, 90 percent of seabirds and 80 percent of shorebirds are threatened with, or at risk of, extinction. The number of identified, non-native species established here is rising and now totals 214. Many non-native species can spread rapidly and some affect native species and habitats. 

Estuaries and living habitats, like seagrass meadows and kelp forests, provide marine life with the food and shelter they need to thrive. Many biogenic habitats are decreasing or under threat. A decline in the number of kuku (green-lipped mussel), from over 100 million in 2007 to less than 500,000 in 2016, was observed in Ōhiwa Harbour. Declining marine health makes our coasts and oceans less resilient to disturbances, including climate change.

Our activities on land are polluting our marine environment

Our activities on land, especially agriculture and forestry, and growing cities, increase the amount of sediment, nutrients, chemicals, and plastics that enter our coasts and oceans. 

Inter-tidal sedimentation rates have generally increased and become highly variable since European settlement. In estuaries and harbours across the Waikato region, historical sediment accumulation rates were less than 0.5 millimetres per year. After European settlement, rates became unstable, reaching almost 200 times historical rates. Thick deposits of sediment can smother animals and degrade habitats.

Coastal water quality is variable but generally improving nationally although very site dependent. Some pollutants, like pharmaceuticals and cleaning products, end up in the marine environment and the impacts of this are not well understood. Plastic is found throughout the ocean including inside shellfish, fish, and birds. Seabirds and other animals that eat plastic can get sick or die. Citizen science data collected at 44 sites showed more than 60 percent of beach litter was plastic. Pollution affects our ability to harvest kaimoana, swim, and fish in our favourite local places.

Our activities at sea are affecting the marine environment

Our activities on coasts and in oceans like fishing, aquaculture, shipping, and coastal development, provide value to our economy and support growth. 

Since 2009, the total commercial catch has remained stable at less than 450,000 tonnes per year. In 2018, 84 percent of routinely assessed stocks were considered to be fished within safe limits, an improvement from 81 percent in 2009. Of the 16 percent that were considered overfished, 9 stocks were collapsed. 

Fishing has long-term and wide-ranging effects on species and habitats. The accidental capture (bycatch) of seabirds and marine mammals is decreasing but remains a significant pressure on some populations. Seabird deaths in the 2016/17 fishing year were estimated at 4,186. Seabed trawling and dredging have decreased in the last 20 years. About 24 percent of the fishable area has been trawled since 1990. Shallow areas are trawled more extensively than deeper areas, with varying impacts depending on fishing intensity, gear type, and vulnerability of habitat. 

As an island nation, 99.5 percent of our imports and exports move by sea, and shipping traffic and vessel size has increased. Boat traffic is associated with the spread of non-native species and pollution and requires further construction of wharves and coastal infrastructure.

Most of our activities in the marine environment tend to increase in intensity towards the coast and, on top of the pressure from coastal development, this results in coastal environments being most impacted. Coastal waters tend to hold the greatest diversity of species.

Climate change is affecting marine ecosystems, taonga species, and us

Global concentrations of atmospheric greenhouse gas are increasing because of activities like burning fossil fuels for heat, transport, and electricity generation. This is causing unprecedented change in our oceans. 

The rate of sea-level rise has increased: the average rate in the past 60 years (2.44 millimetres per year) was more than double the rate of the previous 60 years (1.22 millimetres per year). Recent data suggests an even faster rate of sea-level rise. Extreme wave events may be becoming more frequent. Roads, bridges, coastal communities, and habitats are at risk from flooding and sea-level rise.

Our seas are warming. Satellite data recorded an average increase of 0.2° Celsius per decade since 1981. Years with an average temperature above the long-term average are more frequent. An unprecedented marine heatwave occurred in the Tasman Sea and near the Chatham Islands from November 2017 to February 2018 during our hottest summer on record.

Warmer seas affect the growth of even the smallest things in the ocean like plankton which can impact the whole food web. Some temperature-related changes in individual species and fish communities have been observed and tohu (environmental indicators that identify trends in the natural world) have changed. 

Long-term measurements off the Otago coast show an increase of 7.1 percent in ocean acidity in the past 20 years. Oceans will continue to become more acidic as more carbon dioxide is absorbed. Shellfish, including oysters, pāua and mussels, are vulnerable to increasing ocean acidity and this poses a risk for the shellfish-farming industry.

Issues are not isolated, but build on each other and cause more harm

The pressures associated with biodiversity loss, activities on land, our activities at sea, and climate change have many effects on coasts and oceans. These can interact and lead to cumulative effects. This is one of the most urgent problems we face in our oceans. Given the complexity of the marine environment and lack of long-term data, the nature of cumulative effects is difficult to predict.

This report looks at the individual and cumulative pressures on kuku (green-lipped mussel). This is illustrative only and helps to build a picture of what the messages in this report mean within the context of a single species. The ability to report on the impacts of changes in the marine environment on species and habitats is often limited by a lack of baseline data, understanding of tipping points, and connections between domains.

Working together across mātauranga Māori and other science disciplines is improving our holistic place-based knowledge that is crucial in understanding cumulative effects. For Māori the whenua and moana are inextricably linked and there is a complement or balance for everything on land in the oceans.

The complexity of our marine environment

Our marine environment is vast, diverse, and complex. It is impacted by our activities both on land and at sea. Here are some examples of the impacts from our activities. 

Infographic showing the complexity of our marine environment, full description below

Our marine environment is vast, diverse, and complex. It is impacted by our activities both on land and at sea. Here are some examples of the impacts from our activities.

Our exclusive economic zone is one of the largest in the world.

Issues interact and have cumulative effects on our marine environment.

Issue 1: Our native marine species and habitats are under threat.

Marine species threatened with or at risk of extinction:

  • Shorebirds (2016) - 80%
  • Seabirds (2016) - 90%
  • Marine mammals (2019) - 22%

An increasing number of non-native species detected, 2010–2017

  • 43% established populations

Issue 2: Our activities on land are polluting our marine environment

Beach litter in New Zealand

  • 61% plastic litter
  • 39% other

Up to 200x - Increase of average annual sedimentation rates and variability in Waikato since Europeans arrived.

Issue 3: Our activities at sea are affecting the marine environment

  • >99% - The amount of New Zealand imports and exports transported by sea.
  • 335,812 km2 - The total trawled area in deepwater fisheries(1990–2016).

Issue 4: Climate change is affecting marine ecosystems, taonga species, and us

  • +2.44 mm Average rate of sea-level rise per year between 1961 and 2018. 
  • +0.2 °C Average temperature increase per decade in New Zealand’s coastal waters.

Map data from NIWA (NODL 1.0), LINZ (CC BY 4.0), Ollivier & Co (CC BY 3.0)

Follow the kuku story through the issues identified in the report

Hide description

What the marine environment means to New Zealanders

Te moana is deeply embedded in our culture, identity, and history.* As an island nation, many of our ancestors arrived by waka and by boat. We are drawn to the coasts and approximately 65 percent of New Zealanders live within 5 kilometres of the sea. Much of our major infrastructure is close to the coast (OECD, 2019).

The Māori relationship with te moana is based on whakapapa and a long history of people who were astronomers, scientists, ocean navigators, fishers, and regulators. Before colonisation, the Māori economy was based on fishing and a comprehensive trading system. Advanced fishing methods were used – some nets used at Maketu in the Bay of Plenty were up to 1,900 metres long. In addition, the people of Muriwhenua in the Far North identified and named hundreds of fishing grounds within 25 miles offshore, including seasonal descriptions and the species present (Waitangi Tribunal, 1988). 

As treaty partners, Māori have a role as kaitiaki of te moana and mātaitai (fish or food obtained from the sea). Kaitiaki are guardians who carry out the act of tiaki and look after, protect, and conserve the resource or taonga; kaitiaki can be a human, animal, or a spiritual being. This role and the close relationships that Māori have with the moana are acknowledged by the Crown and reflected in Treaty settlements and post-settlement agreements.

* In this report ‘moana’ describes a holistic view of our coasts and oceans, although it can have wider and narrower definitions.

Our marine environment is vast, diverse, and unique

New Zealand’s exclusive economic zone (EEZ) extends from 12 to 200 nautical miles from the coast. It is one of the biggest in the world and 15 times larger than our land area. The coastline is estimated at 15,000 kilometres – one of the longest in the OECD – while our population is one of the smallest (LINZ, 2019; OECD, 2019).

As a long, narrow and isolated island nation, our marine environment has a high level of local variation. Ocean currents and diverse undersea landscapes also allow different communities to flourish. Local uniqueness and an extensive Pacific history is reflected in mātauranga Māori (the body of knowledge passed down from Māori ancestors, which includes worldviews, perspectives, and practices). Mātauranga Māori provides knowledge about changes in the environment across generations, and is strongly associated with a place. This pursuit and application of knowledge is continually adapted and incorporated into people’s lives (Ataria et al, 2018; Hikuroa, 2017).

More than 17,000 species have been recorded in our EEZ and the marine environment accounts for up to 30 percent of Aotearoa New Zealand’s biodiversity (Gordon et al, 2010). There is still much to learn about our marine biodiversity and its ecosystems. More than 4,000 currently known species have not yet been studied in detail and new species are discovered regularly. The number of known fish species increases by about 20 species per year and about half of these are new to science (Gordon et al, 2010). 

Our marine environment supports our mauri and wellbeing

When the mauri (life force and essential quality and vitality of living things) of the moana is healthy it enhances the mauri of humans who are in contact with it. In te ao Māori (the Māori world and worldview) people are spiritually connected with the oceans, waitai (water from the sea), and with species and elements of the moana. Waitai also spiritually cleanses and heals wairua (the spirit or soul of a person).

Conversely, an unhealthy mauri has a destructive effect on our mauri. An unhealthy marine environment affects our physical, mental, and spiritual health. It also impacts Māori ability to manaaki tangata (provide hospitality and generosity to others), including providing food for people and guests. This can affect the mana of both giver and receiver of manaaki.

Healthy marine ecosystems provide other essential benefits (or ecosystem services) that are not easy to measure. Some benefits include climate regulation, as oceans take up carbon dioxide, and seagrasses or mussel beds providing shelter for young fish (Geange et al, 2019).

Our marine environment supports our economy and provides jobs, especially in shipping, fishing and aquaculture, and offshore minerals. In 2017, New Zealand’s marine environment was estimated to add at least $7 billion to our economy (Stats NZ, 2019a). This estimate does not cover some sectors of the marine economy like research or education.

Current estimates of the value of the marine economy do not take into account the non-market value of the marine environment, or count the cost of environmental degradation caused by our activities. 

Purpose of Our marine environment 2019

Reporting under the Environmental Reporting Act 2015

Under the Environmental Reporting Act 2015 (the Act), the Secretary for the Environment and the Government Statistician must produce regular reports on the state of our environment.

Under the Act, a report on a domain (marine, freshwater, land, air, and atmosphere and climate) must be produced every six months and a whole-of-environment (or synthesis) report every three years. Each domain report has now been published once (see Environmental reporting series for the full list). The most recent synthesis report, Environment Aotearoa 2019, was published in April 2019. The previous marine report was Our marine environment 2016.

Our marine environment 2019 begins the second cycle of domain reporting. It updates Environment Aotearoa 2019 and Our marine environment 2016 by presenting new data and insights.

As required by the Act, state, pressure, and impact are used to report on the environment. The logic of the framework is that pressures cause changes to the state of the environment and these changes have impacts. The report describes impacts on ecological integrity, public health, economy, te ao Māori, culture, and recreation to the extent that is possible with the available data.

Suggesting or evaluating any responses to environmental impacts is out of scope under the Act. Therefore, this report does not cover the work that organisations and communities are doing to mitigate the issues. It does provide an update on the most recent data about the state of the marine environment. The evidence in this report is a basis for an open and informed conversation about what we have, what we are at risk of losing, and where we can make changes.

A focus on what matters

When reviewing Environment Aotearoa 2015, the Parliamentary Commissioner for the Environment suggested structuring future synthesis reports according to issues, where an issue is defined as:
…a change in the state of the environment that is (at least partly) caused by human activities (pressures) and has consequences (impacts).

Taking a whole system approach, Environment Aotearoa 2019 identified nine priority environmental issues facing New Zealand (table 1).

Four criteria were established to identify and help describe the sense of significance and urgency of the issue:

Spatial extent and scale - how much of New Zealand is affected by the issue?

Departure from natural conditions - is the issue increasing in scale and/or distribution or accelerating?

Irreversibility and lasting effects of change - how hard is it to fix?

Scale of effect on culture, recreation, health, and economy - how much does it affect the things we value?

This report provides more in-depth information about how the issues in Environment Aotearoa 2019 relate to the marine environment. It focuses on four priority issues identified using the criteria described above.

Table 1 has more detail about each issue.

This is not an exhaustive list of all the issues our marine environment faces. Some issues have an impact on the marine environment but are not featured as they do not rank as highly against the criteria as other issues.

For each issue, this report addresses four questions:

  • Why does this issue matter?
  • What is the current state of this issue and what has changed?
  • What has contributed to this issue?
  • What are the consequences of this issue?

The final section describes how the effects associated with the four issues overlap and interact in local environments, resulting in cumulative effects. This can sometimes offset impacts but more often results in new or increased impacts. To demonstrate this we have woven the story of kuku (or kūtai), the New Zealand green-lipped mussel, through each issue. Kuku are an important traditional food source for Māori and considered a significant taonga (treasured object, resource, idea, or technique). 

Our marine environment 2019 also describes significant gaps in our knowledge that, if filled, would improve our ability to respond to the issues identified in this report.

Table 1: How issues covered in this report relate to the themes and issues identified in Environment Aotearoa 2019

Themes from EA2019

Issue from:

Environment Aotearoa 2019 (EA2019) identified nine priority environmental issues across all domains.

Relates to issue in:

Our marine environment 2019 (this report) discusses four priority environmental issues in the marine domain.

New data and insights since EA2019
Our ecosystems and biodiversity 1. Our native plants, animals and ecosystems are under threat 1. Our native marine species and habitats are under threat New data on:
  • first review of the state of key biogenic habitats using nationally-available data
  • conservation status of marine mammals
  • non-native species 

How we use

our land

2. Changes to the vegetation on our land are degrading the soil and water

3. Urban growth is reducing versatile land and native biodiversity

2. Our activities on land are polluting our marine environment

New data on:
  • beach litter
  • broadened body of evidence for water quality and sediment
Pollution from our activities

4. Our waterways are polluted in farming areas

5. Our environment is polluted in urban areas

How we use our freshwater and marine resources

6. Taking water ecosystems changes flows which affects our freshwater

7. The way we fish is affecting the health of our ocean environment

3. Our activities at sea are affecting the marine environment New data on:
  • fish stocks
  • bycatch
  • marine economy
Our changing climate

8. New Zealand has high greenhouse gas emissions per person

9. Climate change is already affecting Aotearoa New Zealand

4. Climate change is affecting marine ecosystems, taonga species, and us New data on:
  • sea-level rise
  • ocean and coastal sea-surface temperature
  • ocean acidification
  • ocean and coastal extreme waves
  • primary productivity
    All our activities put cumulative stress on the marine environment.  

Information for this report comes from many sources

Data, upon which this report is based, came from many sources including Crown research institutes, central government, and regional councils. Further supporting information was provided using a ‘body of evidence’ approach. This is defined as peer reviewed, published literature, and data from reputable sources. This also includes mātauranga Māori and observational tools used to identify changes in an ecosystem.

These signs and signals of the natural world, ngā tohu o te taiao or tohu, are often referred to as environmental indicators. Māori environmental practitioners use them to identify trends or changes in the state or health of marine environments, for example stingrays as an indicator of seabed health (Faulkner & Faulkner, 2017). Data related to the sustainability of fisheries was sourced from recently published literature like the 2018 Aquatic Environment and Biodiversity Annual Review (Ministry for Primary Industries, 2019).

All the data used in this report, including references to scientific literature, was corroborated and checked for consistency. The report was reviewed by a panel of independent scientists. The indicators related to the marine environment and the date they were last updated is available in the Environmental reporting series.

Supporting information is available

This report is supported by other products that are published by the Ministry for the Environment and Stats NZ: