An official website of the United States government.

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Ballast Water

Ballast water is one of the major pathways for the introduction of nonindigenous marine species. Ballast water is fresh or saltwater held in the ballast tanks and cargo holds of ships. It is used to provide stability and maneuverability during a voyage when ships are not carrying cargo, not carrying heavy enough cargo, or when more stability is required due to rough seas. Ballast water may also be used to add weight so that a ship sinks low enough in the water to pass under bridges and other structures.

Usually, ballast water is pumped into ballast tanks when a ship has delivered cargo to a port and is departing with less cargo or no cargo. Ballast water is then transported and released at the next port-of-call where the ship picks up more cargo. If a ship is receiving or delivering cargo to a number of ports, it may release or take on a portion of ballast water at each port. In such cases, the shipís ballast water contains a mix of waters from multiple ports.

The release of ballast water may introduce non-native organisms into the port of discharge. These introduced species, or bioinvaders, are also referred to as exotic species, alien species, and nonindigenous species. (Source: Massachusetts Institute of Technology Sea Grant - Ballast Water)

Ballast water release

Discharge of ballast water from cargo ship

Spotlights

  • IMO-Norad Project to Demonstrate Solutions for Greenhouse Gases and Biosafety

    • Dec 14, 2021
    • International Maritime Organization.

    • A newly signed project is set to provide pilot projects in developing countries in order to demonstrate technical solutions for biofouling management, address the transfer of invasive aquatic species and help reduce greenhouse gas emissions from ships. Biofouling is the accumulation of aquatic organisms on wetted or immersed surfaces such as ships and other offshore structures.

      The project complements the existing Global Environment Facility (GEF)/United Nations Development Programme (UNDP)/IMO GloFouling Partnerships Project, which aims to support its lead partnering and partnering countries to implement IMO's Biofouling Guidelines (PDF | 134 KB).

  • Canadian Minister of Transport Announces New Regulations to Help Prevent Spread of Aquatic Invasive Species in Canada

    • Jun 23, 2021
    • Transport Canada.

    • Canada's coasts and waterways are vital to our environment, livelihoods, and economy, and must be protected. Ballast water, which helps keep vessels stable in the water, can accidentally introduce and spread aquatic invasive species, like the zebra mussel, if released in the water untreated. To further protect Canadian waters, the Government of Canada is taking action to limit the introduction and spread of aquatic invasive species in ballast water. Today, the Canadian Minister of Transport announced the coming into force of the new Ballast Water Regulations to strengthen existing rules for vessels on international voyages and the introduction of new rules for vessels which remain in Canada and on the Great Lakes. These regulations, which replace the Ballast Water Control and Management Regulations, apply to vessels in Canadian waters and to Canadian vessels anywhere in the world. Vessels are now required to:

      • plan their ballast water management and reduce the number of organisms in their ballast water, typically by installing a ballast water management system; and
      • carry a valid certificate, keep records, and be regularly surveyed and inspected. Smaller vessels may follow an equivalent approach tailored to their operations and size.

      For more information, see Managing Ballast Water and Backgrounder: Ballast Water Regulations.

  • Addressing Invasive Species in Ships' Ballast Water - Treaty Amendments Enter into Force

    • Oct 14, 2019
    • International Maritime Organization.

    • Amendments to an international treaty aimed at preventing the spread of potentially invasive species in ships' ballast water entered into force on 13 October 2019. The International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004 (the BWM Convention) was adopted by the International Maritime Organization (IMO), a specialized agency of the United Nations, to address this problem. The BWM Convention entered into force in 2017. The amendments formalise an implementation schedule to ensure ships manage their ballast water to meet a specified standard ("D-2 standard") aimed at ensuring that viable organisms are not released into new sea areas, and make mandatory the Code for Approval of Ballast Water Management Systems, which sets out how ballast water management systems used to achieve the D-2 standard have to be assessed and approved. This will help ensure that aquatic organisms and pathogens are removed or rendered harmless before the ballast water is released into a new location – and avoid the spread of invasive species as well as potentially harmful pathogens.

Selected Resources

The section below contains highly relevant resources for this subject, organized by source.

Partnership
  • Aquatic Invasive Species Network - Pacific Ballast Water Group

    • Pacific States Marine Fisheries Commission.

  • GloBallast Partnerships Programme

    • GloBallast Partnerships Programme.

    • Building Partnerships to Assist Developing Countries to Reduce the Transfer of Harmful Aquatic Organisms in Ships’ Ballast Water, simply referred to as GloBallast Partnerships (GBP), was initiated in late 2007 and is intended to build on the progress made in the original project. This was initially planned as a five-year project, from October 2007 to October 2012, but was extended until June 2017.

  • GloFouling Partnerships

    • International Maritime Organization; United Nations Development Programme; Global Environment Facility.

    • GloFouling Partnerships is part of the wider efforts by the International Maritime Organization (IMO), in collaboration with the United Nations Development Programme (UNDP) and the Global Environment Facility (GEF), to protect marine ecosystems from the negative effects of invasive species. This work began in 2001 under the GloBallast Programme.

Federal Government
International Government
State and Local Government
Academic
Professional