Harbor porpoise calls tracked near Fort Worden with 'C-Pod' device
Pacific Biodiversity Institute
A Puget Sound harbor porpoise breaches.
Pacific Biodiversity Institute
The C-Pod underwater listening device before it is deployed in the Salish Sea off Port Townsend to record the sounds of harbor porpoises.
By Joe Smillie
Peninsula Daily News
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The Port Townsend Marine Science Center is working with the Winthrop-based Pacific Biodiversity Institute to track a seemingly-recovering population of harbor porpoises.
The marine life organizations placed a high-tech sonar monitor called a C-Pod under the water off the Fort Worden shoreline last month, a de facto microphone tuned in to hear the porpoises' calls.
“There hasn't been as much research in them or interest in them because they are a bit shy. They're not as social or active as orcas,” said Jean Walat, the marine science center's program director.
The biodiversity institute seeks to assess the population of harbor porpoises.
Aileen Jeffries, who is managing the project for the Pacific Biodiversity Institute, said the porpoises were seen regularly up into the 1950s, but were then reported by many area newspapers as extinct in the 1990s.
“We hope they're coming back. That's what we're trying to determine,” Jeffries said.
The Puget Sound Partnership, the agency leading cleanup efforts of the Washington waterway, considers the harbor porpoise a sentinel species — a recovery of the population could be related to a cleaner Puget Sound.
“Because our resident harbor porpoises don't migrate beyond the Salish Sea, they can provide valuable information on the health of our local waters,” said Chrissy McLean, program coordinator for the marine science center.
“They're an important piece in the food web in Puget Sound,” Walat said.
“They soak up a lot of toxics and eat up fish. So if they're doing well, the Sound is doing pretty well.”
Though the National Oceanic and Atmospheric Administration is supposed to take stock of the porpoise population every three to five years, Jeffries said a lack of funding has kept the agency from doing so for the past 10 years.
Pacific Biodiversity Institute has been using acoustic monitors and volunteer spotters to track porpoises in Burrows Pass near Anacortes since 2011.
In addition to the Port Townsned monitor, the institute also placed a C-Pod in Rosario Strait off Cypress Island.
The monitors are aimed at defining the porpoises' territory, which is believed to reach as far south as Nisqually.
The C-Pod acts much like a game camera, Jeffries said, clicking on when it picks up the sound of a porpoise.
It then records the sound and stores it until crews retrieve it every few months.
The porpoise communicates with a sonar frequency in the range of 120 to 140 kilohertz, well above the 100 khz orcas use to communicate.
“So the porpoise adaptation is a predator-prey sort of thing. So they're echolocating where orcas can't hear,” Jeffries said.
“If I was a porpoise, I'd do the same thing.”
Port Townsend Marine Science Center has hydrophones set up at its marine exhibit that allows visitors to push a button to listen to orcas and other mammals communicating underwater.
The science center also is looking to put together a volunteer network for people to watch for porpoises from the Fort Worden bluffs and record spottings.
“We feel pretty sure we're going to be doing that in June,” Walat said.
“We just need to make sure we can come up with the funding to put together a coordinated network.”
For more on the project, see the Pacific Biodiversity Institute's website at pacificbio.org.
For more on the Port Townsend Marine Science Center, see ptmsc.org.
Sequim-Dungeness Valley Editor Joe Smillie can be reached at 360-681-2390, ext. 5052, or at firstname.lastname@example.org.
Last modified: February 09. 2014 6:22PM