Government Seeks Public Comment to Develop Ballast Water Policy

15 August 1996

The issue of how to reduce the risk of introducing unwanted marine organisms in ships’ ballast water is the subject of a public discussion paper released by the Ministry of Agriculture.

A symposium organised by the Royal Society of New Zealand in June last year, entitled "Ballast Water - A Marine Cocktail on the Move", decided that ballast water is a quarantine issue and as such was the responsibility of the Minister of Agriculture and MAF.

A discussion paper has been prepared by a consultative group comprising representatives of:

Ministry of Agriculture (MAF)
Ministry of Fisheries (MFish)
Ministry for the Environment (MfE)
Department of Conservation (DOC)
Maritime Safety Authority (MSA)
Ministry of Research Science & Technology (MORST)
Ministry of Health (MOH)
National Institute of Water & Atmospheric Research Ltd (NIWA)
NZ Shipping Federation
Port companies
NZ Fishing Industry Board (NZFIB)
Regional councils

The purpose of the discussion paper is to:

  • inform interested parties about the risks of introducing exotic marine organisms to New Zealand waters by way of the discharge of ballast water or hull fouling on ships;
  • provide information about steps currently being taken to minimise those risks;
  • invite public submissions on control measures to deal with these risks in the future.

Submissions from the public close on Friday 8 November. Following analysis of submissions, MAF, with the assistance of the consultative group, will make policy recommendations (a ”Strategy") on how to effectively manage the risk from ballast water.


What is the problem?

When vessels are plying the seas empty or lightly laden, they require ballast water for stability, steerage, safety and fuel efficiency. Ballast water also limits hull stresses that can cause critical failures of ships’ hull structures. It is therefore an important component of ship strength.

Ballast water is normally taken on in one port, carried to another, and then discharged as cargo is loaded into the vessel. On vessels visiting New Zealand, the quantity of ballast water that is discharged may be as much as 50,000 tonnes for a bulk carrier, or none at all, in the case of some container vessels. During deballasting, organisms from the uptake port may be introduced into the port of discharge and subsequently become established.

Although modern antifouling paints are extremely effective, hull fouling occurs on all vessels over time especially in areas where the paint is damaged or difficult to apply. Vessels arrive in New Zealand with exotic organisms adhering to their hulls and other external structures. There is potential for these organisms to be dislodged or to release reproductive material into the New Zealand waters. Because hull fouling reduces the fuel economy of vessels, hulls are sometimes scraped [de-fouled"] while in port thus increasing the risk.

Furthermore, ships’ voyage and turn around times are becoming faster. Therefore organisms contained in ballast water or adhering to ships’ hulls may be arriving in better condition than previously. The number of ship visits and the volume of ballast water discharged is also increasing. It is therefore possible that the risk of introducing unwanted organisms via ballast water or hull fouling is likewise increasing.

Good evidence exists that new marine species have already been introduced to New Zealand via ballast water or the hulls of vessels. A number of exotic species of seaweed, molluscs and crustacea are suspected to have arrived in ballast water.

Shipping is vitally important to an island nation such as New Zealand with more than 90% of imports and exports (by value or volume) travelling by sea. New Zealand’s dependence on shipping must be taken into account in considering proposals for risk management reduction.

What Are the Likely Consequences of New Marine Introductions?

Predicting the impact of new marine species, if these become established, is extremely difficult. The origins of and the range of species that may be in ballast water or on ships’ hulls is enormous. While the consequences of some introductions may be benign or even beneficial, it is logical to take a precautionary approach in order to minimise the risk of introducing any new marine organisms.

Three areas have been identified where harmful impacts could be expected:

  1. Aquaculture and Fisheries

  2. Aquaculture, commercial and recreational fishing species could be threatened by the introduction of predators, competitors, parasites or disease. Toxic dinoflagellates have an impact on shellfish industries because of the periodic closures and the expensive monitoring programmes needed. Management of an introduced species in an aquaculture situation would, even if possible, add to the costs of the producer, may threaten the viability of the operation and therefore the livelihood of employees. It is unlikely that any introduced disease or predator which affected feral fisheries could be controlled.
  1. Environment

  2. The introduction of invasive species could cause the decline of native marine flora and fauna and permanently reduce species biodiversity in coastal ecosystems. New species could also alter the way New Zealanders use the sea and coastline for recreation. For instance, stinging jelly fish, invasive kelp, sharp shellfish would detract from the amenity value the sea provides for swimming, diving, surfing etc. Introduced species have already altered some previously sandy beaches to unpleasant muddy areas.
  1. Human health

  2. Cholera-causing Vibrio has been isolated from the ballast water of vessels in the United States. This highlights that diseases affecting human health may be present in ballast water. It is probable that other means of introduction of human diseases eg. via aircraft passengers are potentially more significant. However, the relative risk of the introduction of human diseases via ballast has not been quantified. The transfer of toxic dinoflagellate species via ballast water is well-known. These organisms produce toxins which enter the food chain via shellfish and fish. When ingested by humans and other animals, severe illness and even death can result.

Examples of Introductions to New Zealand

  1. Asian brown kelp was first discovered in New Zealand in Wellington Harbour in 1987. It has since been found in the ports of Picton, Lyttleton, Timaru, Oamaru, Otago and Napier where it is frequently seen on moorings, wharf pilings and the hulls of vessels. It has now spread to open coastal areas beyond the ports including the Marlborough Sounds. It has also been recently introduced to the woodchip port of Triabunna in Tasmania, where it is very aggressive. It appears likely that ballast water discharge was the means of introduction.
  2. The Asian date mussel was first noticed in Waitemata Harbour in 1978 where it formed dense mats bound together by fine byssus threads. From there, the organism spread rapidly and now there are extensive beds of it in many shallow subtidal areas from Parengarenga to the East Cape. The mussel mats smother other organisms beneath them and trap fine sediments to form thick mud drifts. The mats continually die off and new patches are established each year. Asian date mussel invasions have turned some recreational areas around Auckland from sand to soft mud.
  3. Arriving in New Zealand in 1964, the Pacific oyster has been a mixed blessing. It quickly out-competed the slower growing New Zealand rock oyster which was the basis of the North Island commercial oyster industry. The industry recognised the economic advantages of switching to the fast growing Pacific oyster and are now able to produce two crops in the time it took to grow one crop of rock oyster. However, invasions of the Pacific oyster into many northern harbours over the last two decades have transformed previously rocky shores and pebbly beaches into unpleasantly muddy and shelly areas spiked with thousands of sharp oyster shells. Large banks of oysters and their shells have accumulated, ponding soft mud behind and resisting all attempts at control.

What Has Been Done So Far to Address the Risk?

  1. New Zealand Ballast Water Guidelines
    Voluntary controls were placed on the discharge of ballast water in New Zealand in March 1992 by the then Ministry of Agriculture and Fisheries. The controls seek to ensure that vessels refrain from discharging ballast water while in New Zealand waters.
    Vessels are requested to exchange ballast water in the open ocean (away from coastal influences) en route to New Zealand and to discharge only the exchanged water from the open ocean whilst in port. Organisms from coastal environments are unlikely to survive in the open ocean and vice versa. These controls are ”voluntary" in the sense that there is no penalty for failure to comply, and compliance with the controls is secondary to any concern that masters may have about vessel safety. However, where a specific biosecurity risk has been identified, controls can be enforced.
    Compliance with the controls is monitored by officers of the MAF Quarantine Service as part of their routine vessel clearance duties. Documentation concerning ballast is checked and has been found to be satisfactory for 97% of vessels checked. However, there is no detailed auditing of the documentation, sampling or analysis of ballast water, or interviewing of the master or crew to check compliance. Therefore, the true rate of compliance is unknown.
    Legislation under the Biosecurity Act 1993 allows for enforcement of ballast water policy but there is no evidence to suggest that an enforced policy would produce any better compliance with the practical application of the controls. It may encourage more accurate reporting.
    The current guidelines relate to ballast water only. Provisions already exist under the Resource Management Act for control of ship and boat maintenance facilities. These provisions relate to the collection and disposal of the residues from vessel maintenance.
  1. International Agreements
    Because more than 90% of New Zealand's exports and imports are carried on foreign flagged vessels, the ultimate practical solution will rely in part on international agreement and internationally acceptable treatment and design solutions.
    New Zealand is contributing to the development of an international agreement covering ballast water discharge at the Marine Environment Protection Committee (MEPC) of the International Maritime Organisation (IMO).
  1. Research
    MAF has funded a two-year research project by the Cawthron Institute. The project will provide detailed information about the ballast tank configurations of ships. A system for categorising vessels according to ballast water management will be devised and simple sampling plan and sampling kit will be developed.
    A research proposal has also been developed by the National Institute of water and Atmospheric Research [NIWA]. The proposed research will provide the background information necessary to assess the risk associated with ballast water in New Zealand and will analyse and compare the risk associated with the introduction of marine organisms in ballast water compared with hull fouling.



Last Updated: 08 September 2010

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