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Marine biosecurity – the risks

The risks posed to New Zealand’s economy and environment through the introduction and spread of exotic marine pest species are considerable, with potentially far-reaching consequences. Amenity values, recreational fishing, commercial fishing (including aquaculture) and coastal installations could all be affected to varying degrees.

Requirements for arriving vessels

Seafarers should be aware that new species can be transported to New Zealand waters attached to their vessels’ hull as fouling growth. This applies to commercial vessels and even relatively small recreational vessels.

Pests may arrive in ballast water if a vessel has not carried out a thorough mid-ocean exchange of the water to be discharged in New Zealand. The Ministry for Primary Industries (MPI) requirement is for at least 95 percent exchange or flow-through of three times the volume of a tank, at a position at least 200 nautical miles from shore and in water at least 200 metres deep.

The requirements for ballast water can be found at:

Good hull maintenance is encouraged for pleasure craft arriving in New Zealand, and inspectors may choose to inspect hulls for fouling. Boats with significant fouling may be required to haul out and clean at an approved facility.

Comprehensive information for all ships and vessels entering New Zealand is available at:

Managing the risk in New Zealand

Nuisance species that have already become established might be spread by commercial coastal vessels or by recreational boats shifting from one location to another (even when travelling by road on a trailer, as some pest species can survive periods out of water).

It is vital that all sectors ensure every preventative action is taken to minimise the chances of spreading unwanted organisms. The documents below have vital information about minimising biosecurity risks.

The statutory authority for biosecurity, including marine biosecurity, lies with MPI.

To report sightings of any suspect organisms, please phone 0800 809 966 (toll-free).

Any questions about marine biosecurity issues can be directed by email to or

Guidelines for minimising risks from your vessel

At present, only voluntary advisory requirements are in place for hull fouling. Commercial vessels should follow a hull maintenance regime such as five-yearly dry docking and inspection and/or cleaning in between dockings.

No cleaning should be carried out in New Zealand waters unless it occurs at a cleaning facility where all water and waste is collected and treated or disposed of on land (for example, at a dry dock or contained haul-out facilities).

If vessels are moored in one New Zealand port or marina for some time and then moved to another domestic port or marina, a diver’s inspection to remove light fouling organisms from the hull and fittings is recommended before departing the first port.

In all cases, the best advice is to clean at your port of origin as close as possible to your departure date.

For more information, read:

Requirements for oil and gas exploration and production

Structures, platforms, drill rigs and specialised vessels that are floated into New Zealand have a high risk of importing marine pests because they are often heavily fouled. In addition, they have often been stationary in the coastal waters of other countries for long periods, where they will have had ample opportunity to pick up exotic species of marine organisms. These species, including mussels, crabs, seaweeds, worms and sea squirts, could become a nuisance or even threaten local industries such as aquaculture by introducing competitive species that will grow on submerged structures such as marine farms.

You are encouraged to make contact with MPI as early as possible, preferably during your planning phase. MPI will work with you to plan how to minimise any biosecurity risk from your project.

Before bringing floating structures, rigs, specialised vessels to New Zealand, please contact Liz Jones, Senior Marine Adviser, Border Standards, MPI, New Zealand. Phone (04) 894 0481 or email

Alternatively, contact the MPI inspectors at the nearest port to your intended place of arrival:

Even if the project does not include any drilling inside New Zealand’s territorial waters, contingency plans may be needed in case the rig needs to be brought into sheltered waters for any reason.

MPI is working with the oil industry to develop guidelines for managing biofouling, preparing biosecurity management plans for specific proposed projects and so on.