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Chapter 11: Oceans

At a glance

New Zealand’s marine area

New Zealand administers the sixth largest marine environment in the world. At more than 4.4 million square kilometres, our marine environment is about 14 times larger than our land area. We use our marine area for many purposes, including transportation, fisheries, recreation, and tourism, and value it for its cultural and spiritual significance.

Our economy and the marine environment

Many of New Zealand’s economic activities depend on our marine environment. More than 99 per cent of our exports are transported by sea. Our marine industries are worth an estimated $3.3 billion (about 3 per cent of gross domestic product), including $1.34 billion in fisheries exports.

Marine biodiversity

Our marine environment contains a diverse range of ecosystems, including subtropical and subantarctic waters, inter-tidal estuaries, and seabed trenches.

As much as 80 per cent of New Zealand’s plant and animal species occurs in the marine environment and 44 per cent of these are not found anywhere else in the world. Little is known about many of New Zealand’s marine species.

Impact of human activities

By international standards, New Zealand enjoys abundant marine resources and healthy marine environments offshore where much of the environment is not easily accessible. About 30 per cent of our marine environment, however, is thought to experience some degree of disturbance from human activities.

As our population and technological capability grow, so do the pressures we put on our marine environment. These pressures include:

  • commercial fishing and trawling, which have the greatest impact on our oceans, both inshore and offshore

  • increasing land development, which has increased discharges of land-based pollution, stormwater, nutrients, and sediments to the ocean

  • marine spills which can put pressure on our marine environment in some areas

  • climate change, which is expected to have a significant impact on our oceans and coasts.

Commercial fishing and trawling

In 2006, the commercial fishing industry caught about 525,000 tonnes of fish in New Zealand waters. Sixty-five per cent of this catch was from fish species that have been scientifically assessed. Of these species, 85 per cent have been sustainably fished. Fifteen per cent have been overfished and rebuilding strategies are in place.

Large commercial vessels conducted about 970,000 seabed trawls between 1990 and 2005. During this period, the area swept by trawls averaged around 55,000 square kilometres each year. Since 1998, the area trawled by large commercial vessels has reduced to about 50,000 square kilometres in 2005, probably due to reductions in the allowable catch for some high-value species. Between 1990 and 2005, an estimated 3.5 million dredges and trawls were undertaken by smaller vessels.

The environmental effects of trawling activity on our seabed are not well monitored.

Water quality at coastal swimming spots

Water quality at our coastal swimming spots is primarily affected by human activity on land. Over the 2006/2007 summer, 80 per cent of the 380 monitored beaches had safe levels of bacteria almost all the time. Only 1 per cent of sites breached bacterial guidelines regularly. Water quality at our beaches appears to have improved in recent years.

Threatened marine species

Of the almost 16,000 known marine species in New Zealand, 444 are listed as threatened. Well-known species of concern include the Hector’s dolphin (both subspecies), New Zealand sea lion, southern right whale, Fiordland crested penguin, and New Zealand fairy tern.

By international standards, a high proportion (62 per cent) of our ocean-going seabirds are listed as threatened. Two species, the Campbell mollymawk and the black petrel, have shown signs of recovery in recent years. However, over the past three years, seven species have had their threatened species status upgraded.

Protecting our marine ecosystems, habitats, and species

A range of measures protect our marine ecosystems, habitats, and species, including marine reserves. Thirty-one marine reserves cover 7 per cent of our territorial sea – a high proportion by Organisation for Economic Co-operation and Development standards. Nearly half of these reserves have been established since 2000, and the area designated as marine reserve has nearly doubled in that same period. However, 99 per cent of our protected area is found in two offshore marine reserves, and some key habitats remain unprotected. Marine reserves are expected to play a significant role in protecting our marine biodiversity.

Fisheries closures are in place for sensitive habitats such as seamounts, and it has been agreed that 30 per cent of the Exclusive Economic Zone will be closed to seabed trawling. Customary restrictions and closures also play an integral part in fisheries management.

Present and future management

In recent years, management of New Zealand’s marine environments has focused on:

  • better understanding the wider ecosystem effects of human activities on our marine environment

  • establishing a national network of marine protected areas.

Recent years have also seen the emergence of innovative local initiatives for coastal management such as in the Fiordland Marine Area.

In future, increasing attention is likely to be given to the impact of introduced species and climate change on our marine ecosystems, fisheries, and marine species.

Land-based pressures on the inshore marine environment and pressures on fisheries stocks are likely to continue to need careful management into the future. Balancing the competing needs of users of our marine area is likely to become more urgent in the future as our population increases and technology advances. Demand will increase for accurate information to help set priorities for the future use and protection of our marine area.