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  Environment » Natural Resources » Coast » Coastal pressures » Marine farming

Marine farming

Mussel farm Marine and freshwater farming (or aquaculture) is the fastest growing agri-business in the world and supplies almost half of the 100 million tonnes of seafood eaten globally. As production from wild fisheries has been static since the mid-1990s, aquaculture has been supplying the growing demand for seafood. New Zealand is a small player, producing a little over 100,000 tonnes of farmed seafood, and is well placed to capitalise on the growing demand by targeting high-end niche seafood markets.

The Waikato is a significant player in the national aquaculture industry, producing about 20 per cent of the green-lipped mussels and 10 per cent of the oysters farmed. The region is poised to become even more important with significant growth of shellfish farming still to occur within the Wilson Bay marine farming zone and the introduction of fish farming.

While marine farming has substantial economic benefits for the region, if poorly managed it could adversely affect the environment and conflict with other uses of the coastal marine area. Waikato Regional Council is the main regulator of marine farming and requires the industry to be good corporate citizens and stewards of the public space they occupy.

Release of the Coromandel Marine Farming Zone for fish farming

Waikato Regional Council is releasing 240 hectares of the Coromandel Marine Farming Zone for the purpose of fish farming, or other types of fed aquaculture. See this page for more detail.

Marine farming in Waikato

Aquaculture began in the Waikato with inter-tidal oyster farms in the late 1960s and mussel farms in the early 1980s. In 1999 the Wilson Bay zone was created, bringing the total area allocated to marine farming to 1500 hectares.

Most marine farms are located around the Coromandel Peninsula, with the main concentrations at Coromandel and Manaia Harbours, and offshore from Wilson Bay in the 1210 hectare zone. These areas offer sheltered waters, accessibility, favourable climate, good water quality and good nutrient levels.

View our marine farm map to see where the farms are located in the region. To download a pdf version use the link below:

Marine farm map

Benefits of marine farmingOyster farms

Employment, income and associated social benefits

In the Waikato region, the industry employs 400 staff (equating to 270 full-time equivalents), split nearly evenly between on-farm operations and processing, and pays $9.6 million in wages. Indirect employment in support industries is estimated at another 100 full-time equivalents. This means that about one in 50 of the working-age residents of the Thames-Coromandel district are employed directly by the aquaculture industry.

A 2007 economic impact assessment of the region’s marine farming industry found that 21,000 tonnes of mussels and 500 tonnes of oysters were being produced annually from 1000 hectares of consented farms. This generated total sales of $35 million, adding $27 million to the region’s GDP. Since then another 416 hectares has been consented for mussel farming in Area B of the Wilson Bay zone.

As many of the mussels grown in the Waikato are processed in Auckland and Tauranga, the economic benefits to New Zealand may be as much as twice that for the region.

Recreational fishing opportunities

Mussel farms provide excellent fishing spots, popular with recreational fishers. Fish such as snapper are attracted to the baby mussels. Fishers are allowed to enter and pass through the farm sites so long as they behave responsibly and avoid damaging the farm equipment and stock.

Reduced pressure on wild populations

Marine farming can reduce the harvest pressure on wild populations, although this is offset by the use of wild fish stocks for fishmeal to feed farmed fish.

Costs of marine farming

Shellfish farming’s potential effects include:

  • exclusion of some other uses and users from the site
  • reduction in natural character and loss of landscape and amenity values
  • depletion of phytoplankton
  • possible vector for the spread of introduced pests
  • build-up of shell debris and organic wastes on the seafloor
  • interference with seabirds and marine mammals.

Fish farming, and other types of aquaculture that involve feeding stock, is more intensive and has additional potential effects, such as:

  • increased build-up of organic wastes on the seafloor
  • release of dissolved nutrients into the water
  • interbreeding of escaped fish with wild populations
  • transfer of pests and diseases to and from the wild populations
  • sustainability of feed supplies.

A number of reports on the impacts of fish farming have been prepared and are available on this page.

Current science projects

Waikato Regional Council is currently conducting a number of science projects to help us better understand the environmental effects of marine farms in the Waikato region and to support the development of management and monitoring strategies. These projects are particulalry focussed on the anticipated introduction of fish farming to the region but are also relevant to mussel and oyster farming.

The science projects focus on developing practical approaches to facilitate the sustainable growth and diversification of marine farming in the Waikato region within a framework focused on minimising environmental risk. To find out more about our current science projects see this page.

Managing marine farming’s effects

Many of marine farming’s potential effects can be avoided or reduced by careful management, which has improved with experience. While some effects cannot be avoided altogether, the severity of the impact can be reduced to a level that is sustainable if the farms are well managed and placed in appropriate locations.

Waikato Regional Council imposes stringent conditions on the operation of any marine farm consented by the council, including environmental monitoring requirements. The council is developing environmental performance criteria for marine farms. These will identify thresholds or trigger points in the monitoring data that will require the farm operator to adapt their management to reduce their impact on the environment. 

Waikato Regional Council policy on marine farming

The council’s policy on marine farming is stated in the Regional Coastal Plan. The plan acknowledges marine farming’s importance in helping provide for the economic and social wellbeing of people and communities. The council’s objective is that marine farming develop in an efficient and sustainable manner which avoids adverse effects as far as practicable. The policies in the plan emphasise the following key principles:

  • A precautionary approach is used and adverse effects are remedied or mitigated if they cannot be completely avoided.
  • Safe recreation and navigation should not be compromised.
  • Space allocated to marine farming should be used efficiently.

For a discussion of recent and expected future developments in marine farming see this page.

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