Publications: Research reports and publications

Harmful aquatic organisms - Recommendations for the Auckland unitary plan

9 October, 2012
Cawthron Report 2232. Prepared for Auckland Council.


Policy 12 of the New Zealand Coastal Policy Statement 2010 (NZCPS) requires regional councils to manage risks to marine biosecurity from harmful aquatic organisms (HAOs). Auckland Council contracted the Cawthron Institute (Cawthron) to provide guidance on how to meet this requirement with regard to marine species.

Almost 200 non-indigenous marine species (NIS) have been recorded in New Zealand, most being unintentionally transported here via shipping-related mechanisms such as biofouling on the hulls of ships or carried as microscopic life-stages in ballast water.

Following introduction from overseas, most NIS that establish in the New Zealand marine environment continue to spread domestically, both by natural dispersal mechanisms and by anthropogenic vectors such as vessels and transfers of aquaculture equipment or seed-stock. The uncontrolled spread of HAOs has the potential to affect important values at regional scales or greater. As many species can be difficult to control in the marine environment, any new species that are introduced from overseas or from other regions within New Zealand are likely to become a permanent part of the marine biota.

While the Biosecurity Act 1993 (BSA) sets out the statutory functions and powers of central and local government with respect to managing HAOs, the Resource Management Act 1991 (RMA) can also be used to manage vectors and pathways. Until such time as BSA amendments for pathway management are enacted by Parliament and their means of implementation become clearer, the RMA provides the most effective legislative basis for managing pathways for HAOs.

We consider that the Auckland Unitary Plan could contain a single overarching objective for marine biosecurity that promotes positive outcomes for the Auckland region. The objective could be: "To reduce as far as reasonably practicable the risk of introduction and spread of harmful aquatic organisms, in order to minimise adverse effects on values of the Auckland coastal marine area."

The emphasis on reducing spread recognises that established marine HAOs are difficult to eradicate and that on-going control requires the long-term commitment of significant resources. The poor track record of attempts to manage established species have generally led to an emphasis on managing vectors of spread to reduce the risk of initial incursion. This report therefore recommends that Auckland Council adopt an approach based primarily on managing vectors and pathways; however some additional measures are discussed to a limited extent to address risks to areas of special value.

The term 'Harmful Aquatic Organisms' (HAOs) is used in the NZCPS and so is retained here, although in this report it isused to refer to only marine species.