Cabot Strait - Oceana Canada


Tracking ship speeds to protect whales


In recent years, North Atlantic right whales have been seen in the Gulf of St. Lawrence in pursuit of their food source, which has been moving further north due to climate change. Right whales enter the Gulf through the Cabot Strait, an area with busy shipping traffic, located between Nova Scotia and Newfoundland.

It is almost impossible for a fast-moving ship to avoid colliding with slow-moving right whales. A vessel strike can result in painful cuts from propellers or death, further devastating this critically endangered population. Researchers have found that pregnant females and mothers with calves may be more susceptible to vessel strikes, as they spend more time resting and nursing at the surface.

Transport Canada identified the Cabot Strait as an important area for right whales and in early 2020 announced a trial voluntary slowdown in the area to 10 knots for ships longer than 13 metres. Slowing vessels down to 10 knots or less can reduce the lethality of a collision by 86 per cent. 

During the 2020 and 2021 trial slowdown in the Cabot Strait Oceana Canada tracked the speed of ships. 68 per cent of vessels travelled at speeds over 10 knots, 43 per cent exceeded 12 knots. Speeds at which a whale is not likely to survive a collision if struck by a ship.

Find out more in this report >>

Tell the government to take immediate action to protect North Atlantic right whales from extinction. Speak up now, before these iconic whales are gone forever >>


Oceana’s Ship Speed Watch allows users to monitor ship speeds in voluntary and mandatory speed restricted zones that were established to protect marine mammals like North Atlantic right whales along the East Coast of Canada and the United States in near-real time. When mandatory and enforced, speed restriction zones can help prevent collisions with ships, one of two leading causes of North Atlantic right whale injury and death. Ship Speed Watch was created using Automatic Identification System (AIS) data from Global Fishing Watch, an independent non-profit founded by Oceana in partnership with Google and SkyTruth, which uses cutting-edge technology to interpret data from various ship tracking resources. AIS was initially designed as a safety mechanism for ships to avoid collisions at sea. Using ship identifying information reported by operators, AIS can be used to monitor and track ship movements over time since it transmits a ship’s identity, speed, and GPS location.

Please be patient as the Ship Speed Watch tool loads. Once the map appears, it will be positioned off the coast of the U.S. To view Canadian waters and the Cabot Strait, pull the map down. The map can be viewed best on a larger screen. If on a mobile device, ensure your screen is horizontal. If you have questions about this tool, please contact

Click here to learn how to use this map >>

To read the methodology of how this map was developed, click here

*Ship Speed Watch uses vessel information in the Global Fishing Watch database. This information is transmitted from a vessel’s Automatic Identification System (AIS) device, which is collected via satellites and terrestrial receivers. Faulty AIS devices, user error, intentional manipulation, crowded areas, poor satellite reception, and transmission flaws are factors that contribute to noise and errors in AIS data, and sometimes those inaccuracies can be reflected in the speed and location of a vessel. Vessel operators can accidentally or purposefully enter false information into their ship’s AIS thus concealing their identity or location. In crowded areas, such as ports, the massive number of radio transmissions can crowd the bandwidth of satellite and terrestrial receivers, leading to inaccuracies as well. For these reasons, Ship Speed Watch information must be relied upon solely at your own risk.