Hydrophones under the PTMSC Dock
Orcas are very social creatures.  They communicate with one another using underwater vocalizations.  What can we find out about these remarkable animals by listening in?

With the help of hydrophones, or underwater microphones, we can learn a lot, including which pods are nearby and what they are up to.

Port Townsend Marine Science Center is part of the Salish Sea Hydrophone Network, a team using hydrophones to investigate the communication and movement of killer whales through our inland waters.  The photo on the right shows a diver installating hydrophones under the PTMSC pier. 

When you visit PTMSC you can listen to underwater sounds as they are picked up by our hydrophones. We have listening stations inside the Marine Exhibit and on the outside of the building. Ask one one of our docents show you how to use them.

Or listen right here to vocalizations from an orca superpod recorded on our hydrophones in 2010!

The Salish Sea Hydrophone Network
This growing coalition of scientists, educators, and citizens is working to expand a regional network of hydrophones around the Salish Sea, the area shown on the map to the right that includes Puget Sound, the San Juan Islands and the Strait of Juan de Fuca. The Network currently has five hydrophone stations at the locations indicated. You can listen to real-time sounds from each of them by visiting the website of the Salish Sea Hydrophone Network.  

What kinds of sounds might you hear?  You may hear the sounds of orcas communicating with each other, or you may hear vessel noise from ferries, freighters or small motor boats. Other marine mammals make sounds as well, as do marine invertebrates such as shrimp.  Some sounds resemble those of orcas but may actually be squealing ship noises or logs rubbing together. You have to listen carefully to figure out their source.

Listen to sounds coming from our hydrophones (or others on the Salish Sea Hydrophone Network)
Follow these steps:

  • Go to, scroll down a bit, and you'll see a list of hydrophones and webcams to choose from.
  • To hear sounds from our hydrophone, click on the link LISTEN TO THE PORT TOWNSEND MARINE SCIENCE CENTER.  (On most computers, a free audio player player will automatically open and you should be able to recognize the sound of moving water.)
  • Just listen for a while.  Can you identify any killer whale sounds or human noise sources like ships, boats, pile driving, or sonar? 

Sounds picked up by the hydrophones are recorded automatically and are stored for later analysis. These recordings are processed by computers---and by human listeners.

As the study progresses, we are finding that humans are at least as important as computers in detecting orca calls.  People are often better at recognizing orca sounds, but they aren't always listening; the computer is always listening, but it sometimes misses the orcas.

Take part in hydrophone research! Help us notify researchers when orcas are nearby!
You can contribute to this research by listening to the sounds coming in from our hydrophones. You can do it whenever you have time, and you can use on your own computer.

People all over the world are listening – in their time zones, while others sleep – and reporting their findings.  Together we are compiling data that will give us information about the patterns of vessel noise, as well as insights into the movements of orcas in this area.  PTMSC is using this information as part of its orca community education, raising public discussion about ways we can protect local orca habitat.

Hydrophones on the Water
Portable hydrophones, lowered from a small boat, are also being used to help find out whether marine mammals might be affected by tidal energy projects. Snohomish County PUD is preparing to place several tidal energy turbines in nearby Admiralty Inlet as they look at opportunities for alternative energy generation. In 2010, the PTMSC worked closely with the Orca Network, Sea Mammal Research Unit and The Whale Museum to learn how the endangered Southern Resident Killer Whales use the waters of Admiralty Inlet in the area under consideration for these turbines. 

From historical data, we know that groups of whales travel through Admiralty Inlet about 20 times a year, most frequently in the fall when they are thought to be feeding on chum salmon moving into South Puget Sound. 

During the 2010 study, researchers from PTMSC and their project partners leapt into small boats with an array of hydrophones as orcas came through, hoping to answer a range of questions:  What type of sounds are they making? What depths are they using locally?  Which individual whales can be identified?  Are they traveling, foraging or socializing?  Answers to these questions will help give us as a snapshot of “typical” ways that orcas use this area.  This information will be used to decide where and how tidal turbines will be placed so as to minimize environmental impacts to these endangered animals. 

For more information on the tidal power project in Admiralty Inlet, visit the information page at Snohomish County PUD.