Discharge, noise, light and concerns for marine life from anchored vessels

Transport Canada regulates all vessels in Canadian waters including those at anchor. Vessels that do not comply are penalized and can be barred from Canadian waters.

Due in part to the growth in Canada’s trade activities, some regions, particularly Southern British Columbia, have experienced an increase in use of anchorages for vessels in the last decade.

Through the Anchorages Initiative, under the Oceans Protection Plan, Transport Canada officials are examining ways to reduce anchorage use and transits by commercial vessels, while also advancing active traffic management solutions to mitigate socio-environmental impacts and improve traffic management.

To address concerns on the West Coast in the near term, the Government of Canada introduced an Interim Protocol for the Use of Southern British Columbia Anchorages. Results and lessons learned from the interim protocol will help inform the national Anchorages Initiative.

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Discharge from anchored vessels

Most water discharges that you can see are part of normal operations.

Cooling water

Cooling water is recirculated sea water and using it is part of routine vessel operations. For example:

  • cooling down heavy winches used when testing mooring lines
  • draining pressurized sea water lines on deck so they don’t freeze or rupture

Canada Shipping Act, 2001

Sewage system and bilge system water

Sewage system discharge (black water) and bilge system water must be fully treated before being allowed to go overboard.

Vessel Pollution and Dangerous Chemicals Regulations s.132 (7) (a) include rules on where discharge can and cannot take place.


Ships are required to report all pollution or threats of pollution to a Marine Safety Inspector or a Marine Communications and Traffic Services officer. (Vessel Pollution and Dangerous Chemicals Regulations)


Noise from vessels at anchor comes from running:

  • engines
  • generators
  • power tools

When people are on board, vessel noise comes from:

  • ventilation
  • heating

Ships at anchor make less underwater noise than ships in transit, since the main engine and propeller aren’t running.

The Oceans Protection Plan’s Anchorages Initiative is assessing how anchoring affects the environment.


For safety and security reasons, vessels must display:

  • anchor lights
  • deck lights (for vessels longer than 100 m)

Vessels at anchor and “dragging”

A vessel at anchor must have room to swing clear of dangers in the water and of adjacent vessels at anchor. When it changes position or direction, it doesn’t always mean the anchor is dragging. There must be an adequate depth of water under the vessel at all times.

This area of movement is known as the “swing circle” of the anchorage. It is based on the length of the anchor chain, the length of the ship, and other factors. Movement outside of this circle is a sign that the anchor is dragging and action to stop it must happen right away.

The duty officer must track the vessel's anchor at all times, using the ship’s navigation software and radars.

Concerns for marine life

Invasive species introduced through foreign ballast water

Before coming into Canada, vessels may manage their ballast water by exchanging it with new ballast water. The exchange must be carried out from an area:

  • at least 200 nautical miles away (outside Canadian waters), and
  • where the water depth is at least 2,000 m

Canada is working towards updating its ballast water management regulations to meet new standards set out in the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, which came into force in September 2017.

Ballast Water Control and Management Regulations SOR/2011-237

Impact of noise on marine mammals

Under the Oceans Protection Plan, the government is actively working to protect at-risk whales, including the endangered Southern Resident Killer Whale on BC’s south coast.

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