Sunday, August 20, 2006

An orca movie

Rather than write about what I've been up to this past week and a half, I thought I'd show you.

The movie I've made is really a 10-minute sound file illustrated with photos. The soundtrack is entirely orca sounds.

I've been listening to them through my hydrophone so I can get a handle on what the southern residents are trying to cope with in their native habitat, sound-wise. Killer whales' chief sensory capacity is through their echolocation -- they can only see about twenty feet underwater with their eyes, but hundreds of yards with echolocation -- and the presence of manmade sound is, after a paucity of salmon, one of the real survival issues they face. The sound interferes with their ability to hunt and to generally communicate. As you can hear, they are very social animals, and vocalize a great deal even while traveling.

One of the samples gives you an idea what they're up against: In the middle of a relatively quiet set of vocalizations, a boat motor fires up and takes off -- completely drowning out any orca sounds at all. It's worth noting that this was not a whale-watching boat -- it was just a fisherman with a 20-foot recreational boat who was watching the orcas for awhile and got bored.

As the sound samples progress, you'll note that the noise levels increase, especially as more boats began surrounding them. In the canyon walls of San Juan Island's western coast, the constant echoes just add to the general din.

Hope you enjoy. Back to our regularly scheduled political commentary later today.

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