Protecting our marine environment - information for students

Marine pollution can be caused by discharges of sewage, dumping of rubbish from vessels, as well as spills of oil and other harmful substances. Learn about the main maritime environment pollution issues.

What’s meant by the “maritime environment”, versus the “marine environment”?

The maritime environment and the marine environment are both about the sea. The maritime environment is about ships and boats and other man-made things such as oil drilling platforms.

The marine environment refers to the bigger picture of all the living things that live in or on the sea, eg seabirds, marine mammals, fish, snails, shellfish, sponges and seaweed.

The world’s oceans cover 70% of our planet. As New Zealand is an island nation, the health of our ocean, land and people are all linked together. We use the ocean for trade, fun, fishing and food gathering. The beauty and cleanliness of New Zealand's marine environment brings people from all over the world to visit. It is the responsibility of all of us to protect and preserve that environment.


What are the main types of marine pollution from ships?

Unfortunately not everyone is careful about keeping our seas clean and also accidents sometime happen. The main types of marine pollution are listed below.


Every year hundreds of diesel, petrol and oil spills pollute our harbours and coastline. Between July 1998 and October 2008 there were 1581 oil spills reported to Maritime New Zealand! Most of these were for only a few litres, but it all adds up.

a ship that has grounded on rocks loses some containers over the starboard side.

Major spills in New Zealand and beyond



Chemicals and other noxious liquid substances can be a hazard to the marine environment. This includes a wide range of products such as vegetable oil, raw materials from manufacturing and waste or by-products from industry.


We’re talking toilets. Sewage from ships, fishing boats and recreational boats is not just an environmental issue; it’s a public health issue!

Learn more about sewage


No plastic or garbage that is classed as harmful to the marine environment is allowed to be disposed of at sea at any time.

Learn more about garbage

Ballast water

Ballast water is carried in empty ships to provide stability. It is pumped into special tanks in the ship before the voyage begins. Tiny stowaways in the form of marine organisms are also taken on board in the ballast water. When the ballast water is pumped out of the ship into the sea, some of these organisms may become pests, threatening seas, inland waters and fisheries.

Antifouling paints

These paints are applied to the underwater parts of the hulls of commercial and recreational vessels. Antifouling paints prevent or slow down the growth of things like barnacles. They can be poisonous to other sea life, especially if they are scraped off when the boat is being cleaned and not properly disposed of.

Air pollution

The engine exhaust from ships contains greenhouse gases like carbon dioxide as well as sulphur and nitrous oxides. There may also be remainders of unburnt fuel and soot particles. These can be harmful to human health.


Are there laws to stop marine pollution?

All vessels, from the smallest recreational boat to the largest containership must comply with the environmental regulations that protect New Zealand’s seas for everybody.

New Zealand's Marine Protection Rules are made by the Ministry of Transport to stop or control discharges of waste, including oil, chemicals and garbage. Anyone who breaks these rules could have big fines to pay.

Maritime New Zealand also has a responsibility to prevent marine pollution caused by the dumping and disposal of waste from New Zealand flagged ships on the high seas (outside our Extended Continental Shelf (ECS)).

There are also other groups who have responsibility for our coastal and marine environment:

Learn more about the regulations, standards, legislation and conventions for our marine environment.

Environmental regulations


What other threats are there to the marine environment?

Water pollution comes from a lot of different places. The number one reason why our rivers, lakes and beaches get dirty is from pollutants that flow into storm drains in cities as well as urban and rural areas. In addition, farming and the resulting runoff from agricultural activities is a major pollution problem.

Let’s not forget climate change and the greenhouse effect, which affects ocean temperatures and sea levels. This will have a major impact on marine ecosystems and species.


When was the last big oil spill in New Zealand?

Early in the morning of 5 October 2011, the cargo vessel Rena struck Astrolabe Reef 12 nautical miles off Tauranga and grounded.

The 21-year-old 236 metre Liberian-flagged cargo vessel was en route from Napier to Tauranga and travelling at around 21 knots when it struck. Its bow section was wedged on the reef, and its stern section was afloat. Two of its cargo holds flooded and several breaches were identified in the hull. There were 25 crew on board Rena at time of grounding.

2011 11 2
Maritime NZ
View of the Rena from cockpit.

Rena was carrying 1,368 containers and 1,733 tonnes of heavy fuel oil (HFO) on board at the time of grounding. An oil leak was detected on the night of night 5 October and a salvor, Svitzer, was appointed by the vessels owners and insurers the next day.

The salvage team began working around the clock in extremely dangerous conditions to secure the vessel and make preparations for the complex task of pumping the HFO off.

The salvors began removing the estimated 1,350 tonnes of oil in various tanks on Rena on 9 October, but were hampered by bad weather, equipment breakdown and hazardous and changeable conditions.

A storm overnight on 11 October resulted in the loss of an estimated 350 tonnes of oil from Rena, some of it washing up at various points along the Bay of Plenty coastline. Continuing bad weather the following night saw 86 containers lost overboard. A further 5–10 tonnes of oil was lost from the vessel overnight on 22–23 October.

Oil spill response personnel and volunteers, including large numbers of locals, worked to clean oiled beaches and recover debris from the containers. Wildlife experts from the National Oiled Wildlife Response Team treated oiled birds, including little blue penguins and pied shags, and pre-emptively caught 60 rare New Zealand dotterel to prevent them becoming oiled. (These birds were later re-released back into cleaned environments in a staged released programme.)

Over 1,300 tonnes of HFO was eventually recovered from Rena, with all of the accessible oil removed by 15 November. Containers lost overboard during bad weather were intercepted and recovered, where possible, along with dispersed container contents that washed up. Container removal operations from Rena began once all of the oil had been removed, with the first container lifted off on 16 November 2011. By 26 December, a total of 341 containers had been removed.

On 8 January 2012, Rena separated into two pieces and an estimated 200–300 of the approximately 830 remaining containers were lost overboard. The condition of the vessel had been gradually deteriorating during the time it was grounded on the reef, with more accelerated deterioration during stormy weather.

On Tuesday 10 January the stern section of Rena began to change significantly, with about 75 percent underwater by 10am. The stern section completely sank in early April, with the front of the section in around 23 metres of water and the rear in around 65 metres.

MNZ coordinated a massive Tier 3, or national level, oil spill response, recovering around 1,000 tonnes of oily waste from Bay of Plenty beaches and treating hundreds of oiled birds. This operation was formally concluded in May 2012.


What’s so bad about oil?

One of the most visible and distressing effects of an oil spill can be the suffering of oiled wildlife.

Oil damages the waterproofing on birds’ feathers so they get cold and can’t swim, float or fly. The toxic components of oil can render birds unconscious and cause serious or fatal illness. If oil from a bird’s feathers gets into the eggs when it returns to the nest, those eggs probably won’t hatch.

The rescue, care and rehabilitation of oiled wildlife require special training.

Learn more about oil including the following topics by clicking on the link below:

  • what is oil
  • properties of the oils that are commonly spilled in New Zealand
  • what spilled oil looks like
  • oil and its behaviour when spilled
  • identifying spilled oil
  • oil storage and disposal.

Learn all about oil


Who’s responsible for the maritime environment?

Maritime New Zealand is the government agency that helps makes sure New Zealand’s marine environment is safe, secure and clean.

Did you know that Maritime New Zealand owns over $12 million dollars of equipment to contain and clean up spilled oil? This equipment includes booms, pumps, oil skimmers and dispersant chemicals.

Maritime New Zealand is based in Wellington, but also has a team of experts based in Te Atatu. The team is called the Marine Pollution Response Service and is made up of experts in dealing with marine oil spills. As well as cleaning up oil spills, they run training courses to teach others who might be involved in cleaning up marine oil spills. All of the regional councils in New Zealand also have trained oil responders.

Learn more about responding to spills and pollution.

Spill response


How can I get involved?

Marine pollution and oil spills are not just a problem for big ships. If your family has a boat, or you know someone who does, you can help to protect our marine environment by reminding them to dispose of all waste correctly. Don’t just throw your waste overboard. There are special requirements for dealing with oil, oily water, plastics, food waste and sewage.

Most pollution spills by recreational boaties are because of careless refuelling or pumping oily bilge water overboard.

Learn more about the requirements for vessels, installations and ports.

Operational environmental requirements 


World Maritime Day

Every year many countries around the world (including New Zealand) celebrate World Maritime Day. Each World Maritime Day has a theme, which is set by the International Maritime Organization, to focus attention on an aspect of maritime safety and the marine environment.

World Maritime Day [IMO website]


Links to more information

The following list of websites can provide you with more information about protecting our marine environment.

Ministry for the Environment

Learn what you can do to reduce marine pollution.

Ministry for the Environment

Global Marine Oil Pollution Information Gateway

See their pages for kids about oil in the sea. It includes links to lots of other websites.

Global Marine Oil Pollution Information Gateway

International Maritime Organization

Get in-depth information about the International Maritime Organization and the marine environment.

International Maritime Organization

Related information:

School resource

An outline of the causes, consequences and prevention of marine and waterway litter.

[PDF: 438KB, 2 pages]