From now through January, Quiet Sound asks large commercial vessels to reduce their speeds when transiting Admiralty Inlet and north Puget Sound. Past slowdown season results show that by slowing down, ships can reduce underwater noise by up to 50%, making it easier for endangered orcas to hunt and communicate.
SEATTLE, Washington (September 3, 2026) – Quiet Sound, a collaborative program of Maritime Blue dedicated to reducing commercial vessel impacts on the endangered Southern Resident killer whales, announces the start of its voluntary vessel slowdown beginning September 4 through early 2027.
The slowdown provides the remaining Southern Resident killer whales with quieter waters for communicating and hunting. The population, which increased from 74 to 76 whales in the last year, visits the Puget Sound in fall and winter months to feed on salmon. The start of the commercial vessel slowdown was triggered as Southern Resident killer whales were confirmed in Admiralty Inlet on the morning of September 3.
In an area 22 nautical miles long through Admiralty Inlet and north Puget Sound (see map), container vessels, vehicle carriers, and cruise ships are asked to voluntarily slow to 14.5 knots speed through water, while general cargo, tankers, and bulk carriers are asked to slow to 11 knots. By slowing down, large vessels can immediately and significantly reduce their underwater noise.
The success of the 2026-27 slowdown will be measured through noise reduction modeling, participation data from the Puget Sound Pilots, transit data from the Marine Exchange, and analyzed by SMRU Consulting and orca presence reporting from Orca Network.
“Leveraging the three years of data our program has collected, Quiet Sound was able to contextualize the impact our slowdowns are having on the underwater soundscape,” said Rachel Aronson, Quiet Sound Program Director. “The 2025-26 slowdown reduced underwater noise by 40% compared to 2019, before we began implementing voluntary slowdowns in Puget Sound.”
Highlights of the 2025-2026 voluntary vessel slowdown include:
- Over 670 piloted transits reduced their speed when transiting to or from Puget Sound ports, resulting in a 64% participation rate.
- A majority (56%) of transits met speed targets.
- Median broadband sound levels were reduced by 20% compared to months without a slowdown, and noise intensity was reduced by 15-22% in frequencies used by killer whales to echolocate and communicate, respectively.
- Southern Resident killer whales were present in the slowdown area for at least 34 days.
The 2025-26 slowdown report can be found on Quiet Sound’s website.
“The Northwest Seaport Alliance is proud to support Quiet Sound’s voluntary slowdown as a practical, collaborative way to reduce underwater noise and help protect Southern Resident killer whales,” said Commissioner Calkins, Co-Chair of the Northwest Seaport Alliance and Port of Seattle Commission President.
“This effort reflects the maritime community’s commitment to environmental stewardship while maintaining the safe and efficient movement of cargo through our gateway,” said Commissioner Marzano, Co-Chair of the Northwest Seaport Alliance and Port of Tacoma Commission President.
“Respecting and protecting the oceans and marine life is central to our mission and shapes how we operate every day,” said John Haeflinger, Senior Vice President, Maritime Policy and Analysis, Carnival Corporation. “Programs like Quiet Sound complement the measures already built into our operations and give us another meaningful way to reduce underwater noise, help protect Southern Resident killer whales and responsibly navigate the remarkable waters we are privileged to visit.”
Carnival Corporation was awarded a Sustainable Century Award from the Port of Seattle this year for their industry-leading participation in the Quiet Sound slowdown.
Quiet Sound will host a briefing on Monday, October 19 from 9:00-10:30am during One Ocean Week for press, elected officials, and executives of the organizations on the Quiet Sound Leadership Committee to share real-time data of this year’s slowdown and other initiatives.
###
Media Contacts:
- Rachel Aronson, Maritime Blue | rachel@maritimeblue.org
- Northwest Seaport Alliance | info@seaportalliance.com
- Janna Rowell, Carnival Corporation | jrowell@carnival.com
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.
About the Northwest Seaport Alliance
The Northwest Seaport Alliance is a marine cargo operating partnership of the Port of Seattle and Port of Tacoma. We are a leading container gateway in the United States. Under a port development authority, the NWSA manages the container, breakbulk, auto, and some bulk terminals in Seattle and Tacoma.
About Carnival Corporation
Carnival Corporation is the largest global cruise company and among the largest leisure travel companies, with a portfolio of world-class cruise lines – AIDA Cruises, Carnival Cruise Line, Costa Cruises, Cunard, Holland America Line, P&O Cruises, Princess Cruises, and Seabourn. Carnival Corporation Ltd. trades under the ticker symbol CCL on the NYSE and is a member of the S&P 500.