Citizen scientists can help notify researchers when orcas are in the Salish Sea, a network of coastal waterways located between the southwestern tip of Canada's British Columbia and the northwestern tip of Washington State.

The Salish Sea Hydrophone Network is looking for volunteers to help monitor the critical habitat of endangered Pacific Northwest killer whales by detecting orca sounds and measuring ambient noise levels. Volunteers are especially needed to help notify researchers when orcas are in the Salish Sea, which encompasses the waters of Puget Sound and the surrounding area.

Sponsored by a coalition of organizations, including the National Oceanic and Atmospheric Administration (NOAA) and the Whale Museum in Olympia, Wash., the network consists of five hydrophones, microphones used underwater for recording or listening to underwater sounds. Each hydrophone is hooked up to a computer to analyze the signal and stream it via the Internet.

Even though software is used to distinguish animal from other underwater sound, human ears do a better job. So volunteers monitor the network from their home computers anywhere in the world, and alert the rest of the network when they hear whale sounds. Sometimes boats or onshore monitors are deployed to observe the whales while they are making sounds. Researchers hope to learn more about the uses of orca communications and whale migration patterns.