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State of the Environment Environment New Zealand 2007 - Summary Online version Section three: State of the environment
Section three: State of the environment
Oceans
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.
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.
By international standards, New Zealand enjoys abundant marine resources and healthy marine environments offshore, where much of the environment is not easily accessible. 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 occur in the marine environment, and 44 per cent of these species are not found anywhere else in the world.
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:
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commercial fishing and trawling, which have the largest impact on the New Zealand marine environment, both inshore and offshore
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increasing land development, which has increased discharges of land-based pollution, stormwater, nutrients, and sediments to the sea
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marine spills, which can put pressure on our marine environment in some areas
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climate change, which is expected to have a significant impact on our oceans and coasts.
Fishing and the environment
In 2006, around 525,000 tonnes of fish were caught by the commercial fishing industry in New Zealand waters. Of that catch, 65 per cent2 by weight were from fish stocks for which enough information was available to assess the status (sustainability) of the stock (99 fish stocks).
The remaining 35 per cent comprised 519 stocks, the status of which could not be assessed because of insufficient information. For many of these fish stocks, there is no way to assess their status, because long-term data is needed for a meaningful assessment. Many of these stocks record catches of less than 10 tonnes each year, so they are not considered at risk of overfishing.
The 1996 Fisheries Act requires fish stocks to be managed so their numbers stay at or above a target level, which is generally set to allow a maximum sustainable yield. Table 3.2 shows that, of the 99 assessed fish stocks, 85 per cent (84 fish stocks) have been sustainably fished (are ‘near or above’ target levels, ‘probably near or above’ target levels, and ‘possibly near or above’ target levels), and 15 per cent have been overfished (are below target levels).
The 15 per cent of assessed fish stocks that are below target levels have rebuilding strategies in place. They include, for example, orange roughy in the Puysegur area (which has been closed to fishing since 1997).
Table 3.2: Status of assessed fish stocks under the quota management system relative to target levels, 2006
| Stock status | Number of assessed stocks | Percentage of assessed stocks (%) |
|---|---|---|
|
Near or above target biomass levels |
51 |
52 |
|
Probably near or above target biomass levels |
23 |
23 |
|
Possibly near or above target biomass levels |
10 |
10 |
|
Total fish stocks near or above target biomass levels |
84 |
85 |
|
Below target biomass levels |
15 |
15 |
Data source: Adapted from Ministry of Fisheries, 2007a.
Trawling on or near the sea floor is the most widespread fishing activity in the New Zealand marine area that physically affects the seabed. However, the environmental effects of trawling activity on the seabed have not been the subject of extensive research and are therefore not well understood.
Between 1990 and 2005, around 970,000 seabed trawls were conducted by large commercial vessels. During this period, the area swept by trawls averaged 55,000–62,000 square kilometres per year. From a peak of around 67,000 square kilometres in 1998 by 173 vessels, the trawling effort by these large vessels has reduced to around 50,000 square kilometres by 94 vessels in 2005, probably because of reductions in the allowable catch for some species. Maps in Environment New Zealand 2007 show where seabed trawling has taken place. In addition, smaller vessels undertook an estimated 3.5 million dredges and trawls between 1990 and 2005.
Since 2005, the Ministry of Fisheries has been implementing the Strategy for Managing the Environmental Effects of Fishing, which regulates the effects of fisheries to help achieve sustainable use of fish stocks, as well as ecological sustainability.
Seabed fishing
Fishing effort on or near the seabed is known to affect the seabed environment. In Foveaux Strait, oyster dredging since 1863 has caused continuous reef modification and disturbance. This dredging has reduced oyster density. Dredging is known to remove epifauna (animals living on top of the seabed sediment) and damage reef systems. Analysis of oyster fisheries on three continents suggests that this pattern of impact is common in areas trawled.
We still have large gaps in our understanding of the wider ecosystem effects of seabed fishing. Historically, most fisheries management and research has focused on individual species and stocks. While this remains important, efforts have increased in recent years to gain a better understanding of the long-term and ecosystem impacts of trawling and other seabed fisheries activities.
Fishing is the most widespread human activity in the marine environment.
Source: Nature's Pic Images.
Threatened marine species
Of the almost 16,000 known marine species in New Zealand, 444 are listed as threatened. Well-known species of particular concern include both subspecies of Hector’s dolphin, New Zealand sea lion, southern right whale, Fiordland crested penguin, and New Zealand fairy tern.
Table 3.3 shows that a high proportion – 62.3 per cent – of our ocean-going seabirds are listed as threatened. Two species – the Campbell mollymawk and black petrel – have shown some signs of recovery in recent years, but seven species have become increasingly threatened over the past three years.
Table 3.3: Number of marine species and subspecies in the New Zealand Threat Classification System, 2005
Local action to protect the marine environment
Central and local government are primarily responsible for decision-making, planning, and monitoring in the coastal marine area. However, local initiatives have become increasingly important for managing the coastal and marine environment. Council and community initiatives include beach clean-ups, dune restoration programmes, wetlands and habitat restoration, and stormwater management.
In particular, initiatives for the better integration of management in the coastal marine area have been undertaken in recent years. These initiatives focus on the coastal margin and include marine management initiatives such as the Fiordland Marine Guardians and Kaikōura Coastal Marine Guardians (Te Korowai o Te Tai o Marokura).
The Fiordland Marine Guardians began as a local fisheries committee in Fiordland. It grew to include other commercial and recreational fishers, tourist and eco tour operators, dive clubs, and conservationists.
The Fiordland Marine Guardians developed a community-initiated resource management plan to protect and sustain the unique marine environment in Fiordland. This plan included agreement that:
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recreational fishers would limit their daily bag to three cod per person
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commercial fishers would only fish in the open sea and outer fiords
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Ngāi Tahu would not fish under customary right.
This agreement was cemented through the Fiordland (Te Moana o Atawhenua) Marine Management Act 2005. The Act brought into being the Fiordland Marine Area, which extends from Awarua Point to Sand Hill Point, covering about 928,000 hectares. Within the marine area, the Act established eight new marine reserves of 9,520 hectares, in addition to the two pre-existing marine reserves.
Protecting marine areas
Marine ecosystems, habitats, and species can be given protection through various instruments created by different laws. Thirty-one marine reserves now cover 7 per cent of our territorial sea – a high proportion by Organisation for Economic Co-operation and Development standards.
Nearly half of these have been established since 2000, and the area designated as marine reserve has almost doubled in this time. However, 99 per cent of the protected area is found in two offshore island marine reserves and some key habitats remain unprotected.
The objective of the Marine Protected Areas Policy and Implementation Plan is to expand the network of Marine Protected Areas to fully represent the range of New Zealand’s coastal and marine ecosystems and habitats.
Under the Fisheries Act 1996, 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 (see Box ‘Customary fisheries restrictions and closures’).
Milford Sound Marine Reserve – one of a number of marine reserves in New Zealand.
Source: Courtesy of the Department of Conservation.
Customary fisheries restrictions and closures
Provision for customary fisheries method restrictions and closures is made under the Fisheries Act 1996. This includes the use of rāhui, mātaitai reserves, and taiāpure
Rāhui is a traditional marine management tool, which creates a temporary closure of an area. Tangata whenua can ask for ‘mātaitai reserves’ (special management areas) and ‘taiāpure’ (locally managed fishing areas) to cover some of their traditional fishing grounds, or areas that have cultural and spiritual significance.
Within mātaitai reserves, tangata kaitiaki (customary-take guardians) set rules for customary and recreational fishing. Generally, commercial fishing is banned within mātaitai reserves. However, tangata kaitiaki may recommend that some types of commercial fishing be allowed.
Taiāpure are local fisheries in coastal waters that recognise the special significance of the area to local iwi or hapū, either as a source of seafood, or for spiritual or cultural reasons. Taiāpure give Māori greater say in the management of their traditionally important areas.
A major difference between mātaitai reserves and taiāpure is that commercial fishing is often allowed in taiāpure.
At the beach
Water quality at coastal beaches is mostly affected by human activity on land. Coastal beaches generally have lower background levels of bacteria and/or shorter lasting contamination events than river and lake swimming spots, because pollutants are rapidly diluted and dispersed by currents and the large volumes of water at the coast.
Over the 2006–2007 summer, 80 per cent of the 380 monitored beaches had safe water quality almost all of the time. Only 1 per cent of sites breached bacterial guidelines regularly. Water quality at our beaches appears to have improved in recent years, although the record is too short to discern definite trends.
Oil spills
Oil spills have the potential to affect marine biodiversity and habitats. Because of the concentration of shipping traffic, most oil spills occur in ports and harbours. The spill rate for ports is around three times as high as that for all other coastal areas.
By law, ships must report oil spills, but most marine oil spills are from unknown sources and the actual volume of oil spilled is not quantified. Records show a decrease in the amount of reported spills since 1999, and this may be due to improving practices in the fishing and shipping industries.
It is possible that some spills continue to go undetected or unreported, but in spite of a significant increase in shipping and tourism activities in recent years, there have been no large-scale marine spills in New Zealand since 2002.
The 2006 New Zealand Marine Oil Spill Response Strategy aims to minimise the impact of oil pollution on the marine environment within New Zealand’s area of responsibility.
Integrating oceans management
Land-based pressures on the inshore marine environment, as well as pressures on fisheries stocks, can be expected to persist and, therefore, continue to pose a challenge to the health of the marine environment. The increasing number of introduced species brought to New Zealand through marine-based trade and travel, and climate change may exacerbate existing pressures. Further information About our marine environment is needed if we are to help set priorities for future use and protection of our oceans.
In recent years, management of New Zealand’s marine area has started to shift from managing single parts of the environment to managing the effect of human activities on whole ecosystems. One example of this is work towards implementing a national network of marine protected areas and improved management of the impacts of fishing on wider marine ecosystems.
Improving the regulation of environmental impacts in the Exclusive Economic Zone is an emerging priority area. Recent years have also seen the emergence of innovative local initiatives for coastal management, such as that developed in the Fiordland Marine Area.
2 This figure excludes arrow squid, the annual catch limit for which is over 100,000 tonnes. This is because a meaningful stock assessment cannot be made because of its unusual life cycle. Current levels of fishing are, however, considered to be sustainable.
