The hydrophones don’t just pick up Southern Resident killer whales, but also anything else audible underwater. Often, you will hear long stretches of engine noise from a passing freighter, or the louder but briefer transiting of a smaller vessel. Sometimes you can even hear wave action or rain! Most exciting though is to detect other marine mammals.

If you listened to the above clips of Southern Resident discrete calls, you’ll hear an immediate difference in the vibrato calls that are distinct for Bigg’s killer whales.

Bigg’s killer whales aren’t nearly as vocal as Southern Residents, but as their presence in the Salish Sea has increased, they are detected more often on the hydrophones. They are most likely to vocalize after a hunt or when in multi-family social group.
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Bigg’s killer whales aren’t the only population that has increased in the Salish Sea; after nearly 100 years of being hunted to local extinction, humpback whales have also returned. Beginning in 2013, humpback whale song fragments and phrases have been heard on the hydrophones, most often in September-December.

Finally, every year we also get questions about this “heavy breather”, heard after dark on the Haro Strait hydrophones. While usually silent underwater, this is actually a territorial vocalization from a male harbor seal!
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