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Ballast Water

Background of the issue

Ballast water is needed to provide stability and manoeuvrability during a voyage when ships are not carrying cargo, are not carrying heavy enough cargo, or require more stability due to rough seas. It is estimated that 3000-4000 million tons of untreated ballast water are discharged from ships every year in ports, as cargoes are loaded, and in coastal regions, as vessels deballast to reduce their draft and enter ports. Furthermore, it is estimated that more than 10.000 marine species each day may be transported across the oceans in the ballast water of cargo ships and introduced into a non-native environment. Ships that take up ballast water in one area or sea, and then discharge it in another, can seriously disturb or alter the ecosystem by introducing "invasive" micro-organisms which establish themselves in the local environment.

With the expansion of volume and density of international shipping the transfer of harmful aquatic species in ships' ballast water tanks has become the most significant pathway of unintentional introductions of invasive alien species into marine ecosystems. As ballast water may be fresh, brackish or saline, the coastal environment, estuaries and navigable inland waters, are most at risk. The economic, social, recreational and ecological losses/costs of such invasive species are difficult to assess, as the losses of native species and environment restoration to pre-invasion quality are more difficult to determine and quantify.

Apart from affecting ecosystems and contributing to the extinction of native species, and therefore representing a significant threat to biodiversity, invasive alien species may also cause major socio-economic damage. Reported effects on human health deriving from alien invasive species include changes to the native food web and human consumption of contaminated seafood.

International Maritime Organization (IMO)

Canada and Australia were among the first countries to experience particular problems with harmful aquatic species, and they brought their concerns to the attention of IMO's Marine Environment Protection Committee (MEPC) in the late 1980's. Shortly thereafter, the United Nations Conference on Environment and Development (UNCED), held in Rio de Janeiro in 1992, recognized the issue of invasive species as a major international concern. In 1997 the MEPC adopted Guidelines to address the problem in the form of "Guidelines for the Control and Management of Ships' Ballast Water to Minimize the Transfer of Harmful Aquatic Organisms and Pathogens" (MEPC resolution A.868(20)).

The IMO members were requested to follow these Guidelines, which called for the exchange of ballast water in the open ocean to reduce the risk the transfer of harmful species. The Resolution also requested the MEPC and the Maritime Safety Committee to keep the Guidelines under review with a view to developing internationally applicable, legally-binding provisions. Finally after many years of negotiations, the International Convention for the Control and Management of Ships' Ballast Water and Sediments was eventually adopted by an IMO Diplomatic Conference in February 2004.

EU action

The EU's involvement in ballast water management has been limited. The Commission has 'strongly recommended' the ratification of the BWM Convention and has participated in the development of interim measures to reduce the risk of non-indigenous species being introduced through the discharge of ship's ballast water in the four Regional Seas Organisations (HELCOM, the OSPAR Commission, REMPEC/Barcelona Convention and the Black Sea Commission). A useful resource concerning alien species is to be found in the web-based portal for information on biological invasions in Europe (the Daisy EU project) at Only in a few cases has it been possible to estimate the cost of the damage caused by non-indigenous species.

Currently two EU Directives and emerging European policy have an associated impact on the treatment and discharge of Ballast Water (Please see the documents from the workshop on Implementing the Ballast Water Management Convention – the EU dimension).


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