In this section:

Review of the Undaria commercial harvest policy

Submission date: 30 July 2009
Submitted to: Ministry of Agriculture and Forestry Biosecurity

The New Zealand Conservation Authority (the Authority) has repeatedly over the last decade expressed its alarm and frustration at the disinterest at departmental and Government level in preventing the damage to indigenous biodiversity caused by Undaria pinnitifida.

In the context of the current consideration of options to commercialise this seaweed now that it is naturalised in New Zealand, the Authority wishes to once again highlight the characteristics of this seaweed which led to its declaration as an unwanted organism:

  • Short longevity (6-9 months), rapid growth rates (1 cm/day), early maturation (c.a. 40-50 days) high fecundity (millions of spores/plant) and without the strict seasonality as expressed in its natural range.
  • An ability to complete its life history over a wide range of temperatures and in different habitats, ranging from highly modified enclosed harbours to semi-exposed open coast
  • A preference for artificial substrata and rapid growth rates through selective breeding for cultivation
  • Undaria does not have any close phylogenetic relatives in the indigenous marine flora and therefore may out compete native species. The life history of Undaria gives it an ecological advantages over native species which have much more seasonally contained reproduction. Undaria has shown its capacity to live in the full range of environments in New Zealand. No native species have this ability to live in the full spectrum of ecological niches.
  • Undaria is an annual species whereas most native seaweeds are perennial

The risks and possible environmental and cultural impacts of Undaria which will occur whether cultivated or not are considered to be -

  • Competition between Undaria and native understory algal and invertebrate species for space, nutrients and light may represent a major threat to indigenous benthic communities. As the density of the Undaria canopy increases it is highly possible that these species will be excluded, resulting in altered community assemblages.
  • Infestation by Undaria of disturbed areas may lead to extra food availability for grazing invertebrates leading to an increase in population. Grazers may then increase the disturbed area for Undaria to colonise. This may result in further exclusions of larger indigenous species like Macrocystis pyrifera (bladder kelp) if dense stands of Undaria persist. The complex relationship between native grazers and introduced species can upset the natural balance that pertains between naturally occurring species.
  • Undaria infestations have a strong influence on cultural values by the exclusion of native species in the coastal area. Adverse effects on the seabed will ultimately damage the mauri (represents the force that binds the spiritual and the physical) of coastal areas
  • Permanent and irreversible diminished natural character and potential loss of biodiversity values from Undaria impact on nationally and internationally significant areas (including marine reserves and mätaitai) within the marine environment
  • Negative reaction from other marine farmers who may have their farms invaded by Undaria and face control costs to protect their crop
  • Increased risk of Undaria invasion to currently pristine areas
  • Potential for Undaria to affect the paua and kina fisheries
  • Increased financial costs for future protection of the indigenous biodiversity values in the marine environment, which will fall on an already under-funded Department of Conservation, or rate-payer funded regional councils

Undaria behaves differently outside its native environment and any assumptions that are based on such behaviour are likely to prove to be erroneous.

The Authority therefore takes issue with the statement in the Discussion Document that “Undaria is likely to have moderate adverse impacts on the values that marine biosecurity aims to protect”. It is the Authority’s view that the impacts on conservation values are likely to be serious in the long term.

As stated in the Discussion Document, there is a risk that allowing greater commercial utilisation could increase the rate of spread of Undaria and increase its abundance in the areas where it is harvested.

The Authority has particular concern that if commercial harvesting is provided for any of the Undaria species that are already in New Zealand, there will be subsequent pressure to import new varieties with superior consumption qualities, which may prove to be even more aggressive than the strains already present.  The favoured Japanese food variety is not currently in New Zealand but each Government’s desire to promote exports may be used as a reason to bypass sound biosecurity processes and underplay or undervalue the impact on indigenous biodiversity values.

If any commercial farming of Undaria is allowed, the Authority requests that a precautionary approach be taken and that it be confined to one existing infested area where there is already permitted marine farming (the Marlborough Sounds) to allow further evaluation of effects on indigenous ecosystems.

If any commercial farming of Undaria is allowed, it should be integrated with control programmes, and the farmers should be required to pay for monitoring the effects on indigenous biodiversity, and contribute to its protection including restoration through a resource utilisation royalty.

In conjunction with any change to the current management of Undaria, there need to be processes put in place which control the movement of all vessels and marine equipment operating in Undaria-infested waters. Lack of such measures to date have resulted in massive spread of this pest to pristine environments including the Snares and Great Barrier Islands. It is very important that every effort is made to prevent its spread to other high-value pristine areas such as the Chatham Islands, which have endemic algal fauna, other subantarctic islands, and Fiordland.

The Authority is opposed to the lifting of unwanted organism status. If, nevertheless, this is to occur, it should be only after a National Pest Management Strategy is in place so that control action is not left to the discretion of individual regions.

Finally, the Authority cautions against the commercial use of invasive species. Such use creates vested interests that later may create opposition to future efforts to control or eradicate the pest, should technical advances prove that practicable.  New Zealand has a long history of such phenomena, and should be wary of providing financial incentives for invasive species.

In conclusion, the Authority considers that the potential impacts of commercial farming of Undaria have been down played.  The Authority supports Option One and strongly opposes Option Three.

back to top

 

Find out more

Contacts

New Zealand Conservation Authority
PO Box 10420
Wellington 6143
Telephone: +64 4 471 3289
Fax: +64 4 381 3057
Email: nzca@doc.govt.nz