This post is more sonic than visual. The ocean is often thought of as a silent place, but if you listen closely there are often many small sounds, and sometimes more substantial ones. In October I went down to Octopolis with Matt Lawrence and David Scheel. The octopuses were a little quiet on this trip, but the sea itself was full of activity. In particular, this is the time of the year when whales come to Jervis Bay. The whales are mostly Humpbacks, along with several other species. On one of the days we were there, all through the dives we heard calls.
I’d heard whales under water just once before, and the sound was high and delicate. This time a lot of the sounds were much deeper. There was an insistent hoon sound, a growl-pop, a higher cheep-cheep-cheep, and others. I don’t know if all the sounds were made by whales. There are puffer fish down there, and I’ve heard they make strange sounds, though we’d not heard them before now. There are no other large fish we tend to see, just rays. I’ll update this post as I listen further, and any analysis from readers would be welcome.
The recording is from a GoPro camera left at the site, so there are no bubbles or other sounds made by divers. The depth is about 17 meters. We left this camera near a den a little away from Octopolis itself. After a while an octopus took an interest in it, and the result is an opera by octopus and whale.
For the first 1:15 we hear the hoon sounds, and then they are replaced by a growl-pop. In the background there is a constant slight crackle, something all our GoPro recordings pick up. I’ve been assuming that the crackle is made by crabs and other small animals, perhaps shrimp, though I rarely see them down there and I don’t really know where these sounds come from. In the middle of the video the octopus makes its own acoustic contribution. The growl-pop disappears and comes back. At about 5:15 the first of the high, bird-like cheep series appears (see also Act 2) and the growl-pop is giving way to a higher whoop.
Some weeks ago I was at a conference on the evolution of communication at Duke University, and learned in an excellent talk by Erich Jarvis that mice sing and fish hum. When mice sing it is the male courting females. The sound is too high for us to hear – the sea of sound around us is much richer than our unaided ears can tell us. And when the mice’s songs are slowed down enough, Jarvis said, they sound like whales.
Act 2: the octopus has abandoned the camera, which is now face-down on the sea floor. With nothing to see, it listens.
The cheeps merge into slower ascending high sounds – more like whale songs as I’d understood them to be. Some dolphin squeaks might be mixed in; the area is often full of dolphins. This video runs for about 8 minutes and the image never changes, so I’d suggest leaving it going as a soundtrack.
A few nights ago I went to see Colin Stetson play at Le Poisson Rouge in New York. Stetson is remarkable. He creates a complete sonic world, with about three distinct elements, using just a saxophone, played without loops. The clatter of the keys is amplified as percussion; he plays; and he can sing/roar into the instrument as he plays. One song from the CD he has just released is called “High Above a Grey Green Sea,” (currently streamable on his website). In his comments about this piece at the concert he discussed the sounds of a particular sonically anomalous whale.
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