Sound Census

Heres a program from our archives.ambience, Bowhead whale We’re listening to the underwater sounds of Bowhead Whales recorded off the coast of Alaska. For the first time, scientists are using sounds to take a census of these animals. I’m Jim Metzner and this is the Pulse of the Planet.Clark: In the acoustic censusing methods we’ve been using for Bowhead Whales in the Alaskan Arctic, we install arrays of hydrophones underneath the ice during the spring time. The hydrophones are separated by half a mile or three quarters of a mile along the edge of the ice, and when a whale makes a sound, the sound is received on each of the different underwater microphones. Then, by recording those sounds, and then later computing the difference in the occurrence of the sound at the different hydrophones, you can actually back-compute, back-calculate the position of the whale that made the sound.Chris Clark is Director of Cornell University’s Bioacoustic Program.Clark: So once we’ve located a whale, that location from our acoustic information is merged with the sighting information that the visual observers have obtained by looking for them from their perches on top of the ice. And those two types of data, the visual and the acoustic, are combined into a data file, and that is analyzed in order to determine how many whales those represent.More on Bowhead Whales and the acoustic census in future programs. This archival program is part of our thirtieth anniversary celebration. If you want hear more, check out our podcast.

Sound Census

A new way to count Bowhead whales.
Air Date:11/12/2018
Scientist:
Transcript:

Heres a program from our archives.ambience, Bowhead whale We're listening to the underwater sounds of Bowhead Whales recorded off the coast of Alaska. For the first time, scientists are using sounds to take a census of these animals. I'm Jim Metzner and this is the Pulse of the Planet.Clark: In the acoustic censusing methods we've been using for Bowhead Whales in the Alaskan Arctic, we install arrays of hydrophones underneath the ice during the spring time. The hydrophones are separated by half a mile or three quarters of a mile along the edge of the ice, and when a whale makes a sound, the sound is received on each of the different underwater microphones. Then, by recording those sounds, and then later computing the difference in the occurrence of the sound at the different hydrophones, you can actually back-compute, back-calculate the position of the whale that made the sound.Chris Clark is Director of Cornell University's Bioacoustic Program.Clark: So once we've located a whale, that location from our acoustic information is merged with the sighting information that the visual observers have obtained by looking for them from their perches on top of the ice. And those two types of data, the visual and the acoustic, are combined into a data file, and that is analyzed in order to determine how many whales those represent.More on Bowhead Whales and the acoustic census in future programs. This archival program is part of our thirtieth anniversary celebration. If you want hear more, check out our podcast.