Beaked whales are cryptic animals. They spend little time at the surface, and often dive for long periods making them difficult to track. Because of this we do not know as much about the distribution of beaked whales as we do other species; however, since there is a link between low-frequency sonar use and the stranding of these animals, it is important to find out more.
Recent reviews have indicated that under ideal conditions between 23-45% percent of Cuvier´s and Blainville’s beaked whales would be visually sighted during a survey, needless to say that under poor sea conditions these numbers decrease drastically. One way to help us find out more about these animals is the use of acoustic tracking equipment, like the setup that we are using on this cruise.
We are towing a 400 meter cable (photo on right) with four hydrophone units at 200 and 400 meters distance, recording with a sampling rate of 192 k/second, allowing us to monitor a frequency band up to 96 kHz. Since the energy of most beaked whale vocalisations is situated in the 30-50 kHz range we will be able to detect these animals when they are diving and hopefully increase our sighting rate. We are using Rainbow Click (see middle photo, pink dots are beaked whale clicks) and PamGuard programs to monitor acoustic activity.
This helps us in our search of knowledge about these amazing creatures!
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