Ecological Effects

The most common ecological effects of Greenshell™ mussel farming in New Zealand are localised changes to the seabed and water column through the deposition of organic and inorganic material (including shell) from the farm, and the extraction of plankton by mussels.

Planning for a new aquaculture development requires an assessment of these, and other potential environmental effects - to ensure they 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 Greenshell™ mussel farm applicant must provide a comprehensive and independent assessment of the potential ecological effects of the proposed mussel farm (see Legislation section for details of the permitting process). These assessments have added considerably to the depth of knowledge in New Zealand on the ecological effects of mussel farming.

This and other information will be summarised in a technical review of the ecological effects of mussel farming in New Zealand. The review has been commissioned by the Ministry of Fisheries and should be available in late 2008.

*The content of these Ecological Effects of Mussel Farming pages has been independently reviewed by Dr Ken Grange of New Zealand's National Institute of Water and Atmospheric Research Ltd. (NIWA).

References for Ecological Effects of Mussel Farming

Battershill, C., Miller, K. & Cole, R. 1998. The understorey of marine invasions. Seafood New Zealand 6(2): 31-33.
Bohnsack, J. A. 1989. Are high densities of fishes at artificial reefs the result of habitat limitation or behavioural preference? Bull. Marine Science, 44: 631-645.
Cawthron Institute. Fisheries resource impact assessments for marine farm applications in Marlborough Sounds. Cawthron Client Reports Prepared for Applicants. 2004- 2006.
Cole, R.G. 2002. Impacts of marine farming on wild fish populations. Draft research report for Ministry of Fisheries Research Project ENV2000/08 Objective one.
De Jong, R.J. 1994. The effects of mussel farming on the benthic environment. Master of Science thesis. University of Auckland.
Forrest B, Keeley N, Gillespie P, Hopkins G, Knight B, Govier D. 2007. Review of the ecological effects of marine finfish aquaculture: final report. Prepared for Ministry of Fisheries. Cawthron Report No. 1285. 71p.
Forrest, B. 1995. Overview of ecological effects from shellfish farms in the Marlborough Sounds: background information for marine farm applicant. Cawthron Report No. 282 prepared for Sanford South Island Limited, April 1995.
Grange, K.R. 2002. The effects of mussel farms on benthic habitats and fisheries resources within and outside marine farms, Pelorus Sound. Prepared for the Mussel Industry Council. Unpublished NIWA Client Report NEL2002-003, 24p.
Industry Code of Practice summaries & Exotic Disease Response Plan
Kaspar, H. F., Gillespie, P. A., Boyer, I. C. & MacKenzie, A. L. 1985. Effects of mussel aquaculture on the nitrogen cycle and benthic communities in Kenepuru Sound, Marlborough Sounds, New Zealand. Marine Biology 85: 127-136.
Lalas C 2001. Evidence presented for Kuku Mara Partnership, Forsyth Bay. Environment
Court Hearing. Blenheim. Statements of Evidence – Volume 1. October 2001.
Lloyd, B. D. 2003. Potential effects of mussel farming on New Zealand’s marine mammals and seabirds: a discussion paper. Department of Conservation, Wellington.
MacKenzie, A. L. 1998. Blowing the budget? Nutrient resources and the Marlborough mussel crop. Seafood New Zealand, March 1998, pp 41-44.
Markowitz, T.M. 2004. Social organisation of the New Zealand dusky dolphin. PhD. Thesis. Texas A&M University. College Station, Texas.
Markowitz, T.M., Wursig, B. 2004. Distribution, abundance, and group structure of dusky dolphins inhabiting Admiralty Bay New Zealand during Winter 2004, with comparisons to previous years. A report to the Marlborough District Council and the New Zealand Department of Conservation. 29 p.
National Institute of Water and Atmospheric Research Ltd (NIWA). Fisheries resource impact assessments for marine farm applications in Marlborough Sounds. NIWA Client Reports Prepared for Applicants. 2004- 2008.
Ogilvie, S. C. 2000. Phytoplankton Depletion in Cultures of the Mussel Perna canaliculus. Ph.D Thesis, University of Canterbury, Christchurch.
Plew, D., Stevens, C., Spigel, R., Hartstein, N. 2005. Hydrographic implications of large offshore mussel farms. IEEE Journal of Oceanic Engineering 30: 95-108.