April 13, 2023 | Circular No. 11514

Dear Member,

As part of the 2023 measures for the North Atlantic right whale (details in CL 11513), there will be a voluntary slowdown in the Cabot Strait again this spring and fall (April 19 to June 27 and September 27 to November 15, 2023) coinciding with the period when North Atlantic right whales use the strait to migrate into and out of the Gulf of St. Lawrence. We encourge our members to participate in this voluntary slowdown.

Ship agents are an important conduit for information about this voluntary measure to vessels, and we request that members distribute THIS multi-language postcard explaining the slowdown to vessels.


The Cabot Strait slowdown remains voluntary in 2023 after a successful trial during the past three years (2020- 2022), during which vessels significantly reduced their speed, providing important protection for these iconic whales.

Transport Canada monitors vessel speeds through Cabot Strait during the slowdown periods and reports official participation rates. Per those reports, each year of the trial slowdown, particpation increased, but at approximately 50-56% official participation per season over the last two years, there was room for improvement. At the Federation’s request, TC has now provided not only official participation rates, but also rates that include the effort of those vessels that ‘intended’ to participate in the slowdown but exceeded 10 knots for some portion of their transit. While those vessels did not adhere to the speed reduction in the strict sense that would be applicable in a mandatory slowdown, they significanty reduced risk to the whales, which is the goal of the slowdown. Participation “effort” in 2022 was 82% in the spring, and 64% in the fall.

We thank members for your efforts that have made this voluntary slowdown successful, and encourage you to continue and increase participation in the Cabot Strait voluntary slowdown again this year. Please contact the undersigned with questions or comments.


Miako Ushio

Manager, Environmental and Regulatory Affairs