Ecological Effects
The most common ecological effects of oyster farming in new Zealand are: minor, localised changes to the seabed immediately beneath the site through deposition of organic material and shell litter; farm structures altering the area's water flows; and extraction of plankton (small free-floating plants and animals) from the water column by filter-feeding oysters.
Planning for a new aquaculture development requires an assessment of these, and other potential environmental effects - to ensure the effects of the proposed farm or farm extension would not be significant.
The effects of a farm depend on its location and site characteristics (e.g. depth, exposure, currents and seabed habitat type), as well as on its management practices.
As part of the permitting process in New Zealand, a Pacific oyster farm applicant must provide a comprehensive and independent assessment of the potential ecological effects of the proposed farm (see Legislation section for details of the permitting process).
A general principle followed in New Zealand is that aquaculture should be sited over seabed types where there is the least adverse environmental effect.
