Ships are getting on board with a program to make Puget Sound quieter for the region’s endangered orca population.

Sixty-one percent of vessels participated in a voluntary slowdown in the first four weeks, according to numbers released by Quiet Sound, the program of Washington Maritime Blue.

Program Director Rachel Aronson said sound is an essential sense for orcas, but propeller noise interferes with that.

“The propellor spins, it creates little air bubbles that explode and collapse,” said Aronson. “That process is called ‘cavitation,’ and it turns out that cavitation makes a lot of noise at exactly the sound frequencies that the whales need to hunt and communicate.”

The Quiet Sound program started in 2021 with funding from Washington state, federal partners and ports. In phase one, it helped develop a real-time whale alert system.

The voluntary slowdown began at the end of October. It’s estimated only 73 Southern Resident killer whales remain.

The Quiet Sound program has partnered with the shipping industry on this effort.

Vice President of the Pacific Merchant Shipping Association Mike Moore said the industry has experience with a similar Canadian slowdown program, and is excited to do its part to help the endangered whales.

“Three knots has been equated to about 50% reduction in noise,” said Moore. “So, just a little bit of change can have a big impact.”

Patrick Gallagher is the executive director of the Marine Exchange of Puget Sound, which provides ship location data for the Quiet Sound program.

Gallagher said the program has been transparent about its efforts since its inception, and the shipping industry appreciates this. He said people are thinking about what kind of environmental legacy they want to leave.

“We want to think about what type of ancestors we’d want to be,” said Gallagher. “And we’re trying to prove that industry can basically run alongside doing what’s right for wildlife.”

In the next phase of the project, the program is creating an underwater noise map of Puget Sound.

— By Eric Tegethoff, Public News Service (WA)