Intl. agreement on ballast water constraints
18 February 2004 Media Statement
International agreement on ballast water constraints
Associate Biosecurity Minister Marian Hobbs has welcomed an international move to prevent the potentially devastating effects of exotic marine pests such as invasive species of mussels, crabs, jellyfish and toxic algae being spread from ships’ ballast water.
New Zealand is particularly susceptible to marine invasions and has actively pushed for international action to address the management of ballast water.
The convention, which has yet to be ratified and passed into New Zealand law, was adopted at an international conference hosted by the International Maritime Organisation (IMO), the United Nations agency responsible for safety and security of shipping and the protection of the environment from shipping impacts. It has been under discussion for 12 years.
Ships will be required to 'cleanse' their ballast by exchanging it for mid-ocean water on the way to another country. This is a difficult operation and it is hoped that in about five years new treatments, such as filtration and UV treatment to kill the organisms, will have been developed to replace this method.
After 2009, most new ships will be required to meet the convention's discharge standard for treated ballast water. Existing ships will have about five additional years to comply with this standard, as it is more difficult to retrofit treatment systems.
The IMO Secretary-General, Efthimios Mitropoulos, told conference delegates that the introduction of harmful aquatic organisms and pathogens to new environments has been identified as one of the four greatest threats to the world’s oceans.
"Given the international nature of shipping, the only way to address the problem effectively is through the adoption and implementation of a global legally binding instrument," he said.
Marian Hobbs said New Zealand already requires visiting ships to exchange ballast water before discharging in New Zealand ports.
"The new convention will strengthen the ability of New Zealand government agencies to enforce this obligation and introduces a requirement for more effective treatments in the future," she added.
Shipping is the biggest pathway for spreading aquatic pest organisms from their native region, where they may be living in balance with the environment, to new regions where they may become highly invasive and harmful.
Transporting ballast water is essential to the safe operation of ships but it also poses a significant environmental threat. One ship may empty up to 100,000 tonnes of water from an overseas port when taking up cargo and this contains millions of organisms, often in their larval forms, some of which will survive in a new 'home'.
Some of these may become invasive, severely disrupting the native ecology and seriously impacting on the economy and human health of the region of their new 'home'. It is estimated that three to 10 billion tonnes of ballast water are transferred globally each year.