A voluntary slowdown trial for large ships in Admiralty Inlet and north Puget Sound to lessen the impact of underwater noise on endangered killer whales has proven to be successful so far.
The trial, which was originally planned from Oct. 24 to Dec. 22, has been extended to Jan. 12 in order to collect more data. It is led by Quiet Sound, a part of Maritime Blue, an organization that is dedicated to making the maritime industry more sustainable and equitable.
The slowdown is an attempt to better the lives of southern resident killer whales, a distinct population of orcas that spend several months of the year in Puget Sound. These whales are a critically endangered species. There are currently only 73 of them; it is estimated that a stable population would be about 150 to 200 whales.
Vessel noise affects orcas because the animals use echolocation to find the fish they eat. The noise from boat propellers is in the same frequency orcas use to hunt and communicate. The slowdown applies to commercial vessels such as ferries, cargo and carrier ships, vehicle carriers, bulkers, tankers and tug boats.
Quiet Sound held a press event on Dec. 9 at the Seattle Aquarium to share results of the trial thus far. Gov. Jay Inslee and Tacoma and Seattle port commissioners were in attendance. Quiet Sound was created as part of Inslee’s orca recovery task force, a response to the declining number of killer whales.
Quiet Sound Program Director Rachel Aronson shared that 61% of ships in Puget Sound are slowing down by 30 to 50%. The slowdown has protected the whales 75% of the days they were in Puget Sound. Whales were in the slowdown area for 52% of the trial.
“It is going just as we had hoped,” Quiet Sound Project Manager Caitlin O’Morchoe said. “Maybe a little bit better than our worst fears that the whales were not going to show up or no one was going to participate.”
She said it was possible that no whales would be in the slowdown area if they had expanded their foraging area to eat more prey. The southern residents eat fish like Chinook salmon, another endangered species.
Quiet Sound was modeled after the Canadian ECHO program, which has been doing slowdowns for several years for whales off the coast of British Columbia. The ECHO program had a similar participation rate in its first year. Now, six years later, the participation rate is up to 93%.
Quiet Sound installed an underwater microphone earlier this week to collect noise data. Data will be recorded for the rest of the trial and then afterward to compare the amount of noise.
It’s too soon to say if the slowdown is having any effects on whale behavior.
“The real effects are going to be generations to come,” O’Morchoe said.
The long term goal of southern resident killer whale conservation efforts is to return the population to a number that is self-sustaining, but that could take years and would result from a combination of many factors.
