Photo: Members of L pod on November 30, 2024. Photo credit: Marla Smith via Orca Network.
The initiative aims to support endangered Southern Resident killer whale populations by reducing underwater noise from ships that negatively affects communication and hunting behaviors. The slowdown will begin on September 14, 2025 after the Southern Resident killer whales were confirmed in Admiralty Inlet on September 13. It will end on January 11, 2026. The 2024-2025 Voluntary Commercial Vessel Slowdown reduced underwater noise by 35% in the sound frequencies used by killer whales for communication. Southern Resident killer whales were present for the majority of the days the slowdown was in effect.
SEATTLE, Washington – September 13, 2025 – Quiet Sound, a collaborative program of Maritime Blue dedicated to reducing commercial vessel impacts on the endangered Southern Resident killer whales announces the official launch of its voluntary vessel slowdown season beginning today through early 2026.
The effort protects the remaining 74 Southern Resident killer whales. The start of the commercial vessel showdown was triggered as Southern Resident killer whales were reported in the waters off of Seattle on the morning of September 13. The slowdown remains in effect through January 11, 2026, key months for their migration.
Container vessels, vehicle carriers, and cruise ships are asked to voluntarily slow to 14.5 knots speed through water, while general cargo, tankers and bulkers are asked to slow to 11 knots in an area 22 nautical miles long through Admiralty Inlet and north Puget Sound (see map).
“Underwater noise from large vessels is one of the major factors threatening the recovery of the endangered Southern Resident killer whales.” said Rachel Aronson, Quiet Sound Program Director. “Our voluntary slowdown continues to be a safe and feasible action commercial vessels can take to immediately reduce their underwater noise.”
Highlights of the 2024-2025 voluntary vessel slowdown include:
- 66% piloted transits reduced their speed when transiting to or from Seattle and Tacoma ports. This represents the largest absolute number of transits to reduce their speed (571) of any Quiet Sound slowdown.
- 56% of the transits achieved the proposed speed targets.
- Median broadband sound levels were reduced by 12%, and noise intensity was reduced by 35% in frequencies used by killer whales to communicate.
- Southern Resident killer whales were present in the slowdown area for at least 57 days of the 98-day slowdown, more than any slowdown season to date.
“In 2023, Quiet Sound began utilizing a dynamic start, in which the slowdown went into effect after the Southern Resident killer whales were confirmed in Puget Sound,” said Todd Hass, Special Assistant to the Director at Puget Sound Partnership and member of the Quiet Sound Leadership Committee. “In the 2024-25 season, the whales were present for over half the days the slowdown was in effect. This approach helps maximize a quieter environment when the endangered orcas are utilizing their Puget Sound habitat while minimizing impacts to maritime trade.”
The success of the 2025-26 slowdown will be measured through noise reduction estimation, data from mariners and AIS, and whale reporting from Orca Network.
“At MSC we are deeply committed to solutions that protect our planet and marine ecosystems, including voluntary vessel slowdown initiatives,” said Matthew Harris, Port Operations Manager with Mediterranean Shipping Company (MSC). “We are proud to contribute to the successes achieved with Quiet Sound. Only through collective action can we address the world’s most complex conservation challenges and create both an immediate and lasting impact.”
MSC achieved a 94% participation rate in the Quiet Sound slowdown for the second year in a row. In recognition of MSC’s contribution, Quiet Sound awarded the company a Certificate of Recognition.
Quiet Sound will host a briefing on October 20 during One Ocean Week for press, elected officials, and executives of the organizations on the Quiet Sound Leadership Committee to release real time data of this year’s slowdown.
About Quiet Sound
Quiet Sound is a collaborative alliance that aims to reduce the impact of large commercial vessels on Southern Resident killer whales through voluntary measures. It is implementing noise-reduction initiatives, educational campaigns and monitoring programs in the Puget Sound, in coordination with Canadian and United States authorities. Quiet Sound is administered by Maritime Blue, a strategic alliance to accelerate a sustainable and equitable blue economy. News and updates can be found on the Quiet Sound website: https://quietsound.org/. The Quiet Sound team can be reached at info@quietsound.org.