Managing biofouling

Transport Canada is working to protect Canadian waters by limiting the introduction and spread of aquatic invasive species through marine shipping. One of the main ways that invasive species arrive in Canadian waters is from vessel biofouling.

“Biofouling” happens when microorganisms, plants, algae, and animals build-up on structures that are exposed to an aquatic environment, like a vessel's hull. Vessel's biofouling can bring foreign species to Canadian waters, or move them between ecosystems within Canada. These species can become invasive and harmful in their new environments.

This build-up can also increase vessel's drag, which means it needs to use more power to move. This leads to more fuel consumption, higher operating costs, higher greenhouse gas emissions, and increased underwater noise. Since biofouling begins to build up within the first few hours of a vessel being in water, all vessels can transport aquatic invasive species. 

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How Canada manages biofouling

Canada helped develop and supported the adoption of the International Maritime Organization's 2011 Guidelines for the Control and Management of Ships' Biofouling to Minimize the Transfer of Aquatic Invasive Species. These guidelines created a globally consistent approach to biofouling management.

The guidelines recommend vessel operators choose an appropriate anti-fouling system, control biofouling growth in niche areas, keep biofouling management record books, and perform regular maintenance, cleaning, and inspections. The guidelines also recommend designing vessels to reduce biofouling, and educating or training crews on how to manage biofouling. Transport Canada supports the voluntary uptake of these guidelines by vessels in Canadian waters.

Canada is a strategic partner in the GloFouling Partnerships Project, a collaborative initiative between the Global Environment Facility, the United Nations Development Programme, and the International Maritime Organization. The GloFouling Partnership supports the global implementation of the International Maritime Organization's Biofouling Guidelines and helps reduce the risks of spreading aquatic invasive species through interventions at the global, regional, national, and local levels.

In addition, the Government of Canada has adopted the International Convention on the Control of Harmful Anti-fouling Systems on Ships. This convention regulates the use of toxic compounds in systems designed to prevent biofouling from accumulating. It also ensures that all ships over 400 gross tonnage use an anti-fouling system that complies with the convention.

In-water cleaning of vessels

Cleaning a vessel in-water to remove biofouling can be an important part of managing biofouling. It is important to remember that cleaning a vessel in-water could also release organisms and contaminants into the environment. There are new technologies that can help manage these risks by capturing the organisms and contaminants that break-off during cleaning.

In the summer of 2021, the government held an online engagement on developing Voluntary Guidance for Relevant Authorities on In-Water Cleaning of Vessels. During this engagement, industry stakeholders, Indigenous communities, and the public provided their input. Although all vessels should use best practices to manage biofouling, this guidance only applies to in-water cleaning for vessels that are more than 24 metres long.

The guidance recommends that in-water cleaning is done proactively when only “microfouling” (a build-up of slime on a vessel's hull made up of tiny organisms) is present, instead of reactively once a vessel has a build-up of “macrofouling” (an easy-to-see build-up of large organisms like barnacles and seaweed or algae). Vessels with macrofouling have a higher risk of transporting invasive species.

The guidance recognizes there are situations where a vessel may need macrofouling cleaned from its hull. As such, the guidance proposes best practices for cleaning using two methods: clean with capture and clean without capture.

A vessel should be cleaned without capture technology only if the build-up is microfouling, or the owner/operator can confirm that the macrofouling happened locally. However, when cleaning non-local macrofouling, the guidance recommends strict criteria for in-water clean and capture technology to lower risks of introducing aquatic invasive species. This includes capturing the biofouling organisms and treating them to ensure live aquatic invasive species aren't released into the water.

The guidance recommends that relevant authorities decide whether service providers should be allowed to operate in their waters and review requests for vessel cleanings on a case-by-case basis. There's also information on how to verify that cleaning technology meets the recommended criteria.

Anti-fouling systems

A conference to adopt the International Maritime Organization's International Convention on the Control of Harmful Anti-fouling Systems on Ships was held in October 2001. The convention prohibits organotin compounds (tributyl tin or “TBT”) from being used in anti-fouling systems on ships. As of January 1, 2008, organotin compounds on ships must either be removed or sealed.

The convention also sets procedures for implementing controls for any other harmful systems that are identified in the future. In recent years this has included substances like cybutryne.

The sale and use of products like organotin paints is regulated by Health Canada. The Pest Management Regulatory Agency maintains a list of currently registered anti-fouling paints that can be imported, sold, or used in Canada.

The convention also supports other Canadian initiatives. Under the Canada Shipping Act, 2001, the Vessel Pollution and Dangerous Chemicals Regulations apply to all ships in Canadian waters and to all Canadian ships everywhere. These regulations require ships of 400 gross tonnage or more to have an anti-fouling certificate on board. Those that are under 400 tons gross tonnage, but 24 meters or more in length have to have a self-declaration of compliance on board.