Voluntary Vessel Slowdown Season to Protect Killer Whales

Quiet Sound, a collaborative program from Washington Maritime Blue dedicated to fostering a more sustainable environment for Southern Resident killer whales through reduction in underwater noise pollution, has launched its voluntary vessel slowdown season, which runs through early 2024. 

The effort protects the remaining 74 Southern Resident killer whales in the Salish Sea. 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 October 12, 2023. The slowdown period remains in effect through January 12, 2024, key months for their migration.  

Container vessels, vehicle carriers and cruise ships are asked to voluntarily slow to 14.5 kt., while tankers and bulkers are asked to slow to 11 kt. in an area 22 nautical mi. long through Admiralty Inlet and north Puget Sound (see map). 

The results of the 2022 to 2023 Voluntary Commercial Shipping Showdown trial show: 

  • 70 percent of 670 vessels passing through the slowdown area decreased their speed.
  • 53 percent of the transits achieved the proposed speed targets.
  • Median broadband sound levels were reduced by 2.8 decibels, a 45 percent reduction in sound intensity.
  • Southern Resident killer whales were present in the slowdown area for 36 days of the 80-day slowdown (45 percent).

This 2023 to 2024 Slowdown will be monitored using a system of hydrophones, data from mariners and whale reporting from Orca Network, with a participation goal of more than 80 percent this season.

Learn more here.

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