Marine Biodiversity

Biodiversity is all the different types of life – including plants, animals, fungi, and micro-organisms as well as the habitats they live in. Marine biodiversity is the variety of life found in coastal and sea environments.

Why is our marine biodiversity important?

In New Zealand, we spend a lot of time at the beach: swimming, fishing, sailing, surfing, snorkelling, and exploring rock pools.

The sea, and all that lives in it, is very important to Māori, and this is recognised in the Treaty of Waitangi.

As well as this, our $1.3-billion-a-year commercial fishing industry relies on our marine biodiversity – without the variety of life in our seas they would have nothing to sell!

New Zealand’s marine biodiversity is also important internationally. Forty-four percent of the plant and animal species living in our marine environment are not found anywhere else in the world.

Threats to marine biodiversity

Scientists around the world agree that human activity can seriously threaten marine biodiversity. The most serious threats are: 

• fishing 
• pollution, from rubbish such as plastics and chemicals being dropped in the sea 
• land sedimentation – soil and nutrient run-off from the land can have huge effects on our coastal ecosystems 
• changes to physical habitat – for example, damage caused by some fishing methods, such as bottom trawling, which can damage sea-bed habitats 
• boats and people coming from overseas and introducing exotic species to our waters, such as seaweeds like undaria 
• climate change, which may cause ocean temperatures and sea levels to rise.

These threats can: 

• reduce the numbers of fish and shellfish 
• make some species extinct 
• change the way that the ecosystems work so that fish have to change too in order to survive.

Protecting our marine biodiversity

Scientists are doing a lot of research to help us better understand what biodiversity we have, where it is, and what is threatening it.

We also have a range of laws and strategies that aim to protect our marine biodiversity:

The New Zealand Biodiversity Strategy

This is a set of goals that has been set by the government to protect our biodiversity and maintain and restore our remaining natural habitats and ecosystems, such as forests, wetlands, and coastal environments.

Marine Protected Areas

The government is setting up a network of Marine Protected Areas (MPAs) to protect some of our different marine habitats and ecosystems. MPAs might include: 

• marine reserves, which are areas of sea and foreshore where no fishing is allowed 
• restrictions on some fishing methods, especially those that might damage sensitive habitats or ecosystems 
• mātaitai reserves, which are fishery reserves managed by appointed tangata whenua.

Marine Mammals Protection Act

The Marine Mammals Protection Act 1978 protects all marine mammals, such as dolphins, whales, seals, and sea lions, in New Zealand waters. The Department of Conservation manages the Act. Sanctuaries can be set up within New Zealand's territorial sea (up to 12 nautical miles out from the coast of New Zealand) to create a permanent refuge where no one can do anything that might harm particular marine mammal species. A marine mammal sanctuary is different from a marine reserve because it doesn’t necessarily stop all fishing activities – however certain fishing methods might be banned.