Humpback Whale Acoustics Russ request archive this posting
By Bruce Rule - Nov 30, 2015
The most rewarding aspect of posting on the IUSSCAA Message Board has been the observation that many of these postings can be recovered by goggling general subject such as SCORPION or the BOREY and YASEN Class Russian nuclear submarines.
Most of the content of this posting has been previously posted; however, I have not seen it become generally available on the Internet; hence, this summary repost with the request that it be archived.
The use of extremely high time- and frequency resolution processing and display technology – probably still significantly better than is currently available to the scientific community – identified the remarkably detailed structure of the Humpback Whale “20-Hz song” as detected over periods as long as 5-6 hours with signal to noise ratios of at least 10 dB. The song had an average duration of 18 minutes separated by two minute breathing cycles. These events so precisely repeated that the suggestion is that an autonomic response was involved. Speed during these transit events was measured at about three knots. During a unique detection event in the South Atlantic, a pulse rate of 2.7 beats per minute was measured when submerged.
The song consisted of as many as 20-30 simultaneously-radiated, extremely discrete (some signal bandwidth of less than 0.02 Hz) resonances with durations of 20-60 seconds, all occurring between about 20 and 22 Hz. The repeatability of these multi-component songs suggested – but was not confirmed – that they may be unique at the refined measurement level to individual whales. One has to have seen these data displays to appreciate how discrete and repeatable these signals can be within the overall 18 minute periods, characteristics consistent with hydraulically induced resonances within bone structures.