Orcasound is a citizen science project (and app) enabling you to listen to livestreams of audio from underwater microphones off Washington's San Juan Island.
Mostly, you'll hear ships moving through Haro Strait and other boats in the area. But if you listen long enough, you might be treated to some whale song. From Atlas Obscura:
(Lead researcher Scott) Viers developed OrcaSound because he saw an opportunity for engaged citizens to help fill gaps in the study of orcas. The whales have long been well-observed in the summertime, when the weather cooperates and the cetaceans are more accessible to scientists and the Coast Guard, who observe them by boat. But questions have lingered about their lives during other times of the year. Now, in any season, listeners can notify scientific authorities to alert them to the presence of whales, so they can rush out like first responders to collect important data. The orcas have been facing a food crisis in recent years, so their fecal matter can help scientists get a sense of what they're managing to eat, and what their stress levels are like. Having citizens on the line is also an exercise in preparing for the worst, like an oil spill. In such a case, there will be multiple (ear) witnesses to attest to where the whales were at the time.