Quote:
Originally Posted by TLAM Strike
The ACTUV used MF and HF sonar, LF Sonar is what had a negative effect on whales.  |
You're not right, the problem with cetaceans is more about signal power than frequency. HF sonar is less harming because is rapidly absorbed by water, so is not likely to harm nearby cetaceans because they will likely be detected first at those distances, and active sonar use is forbidden in most of the navies when cetaceans are present. LF and MF sounds travel further and then the possibility to reach cetaceans out of visual or passive sonar range increases a lot.
MF sonar range is less than LF, but its accuracy is better so, what to do to increase detection range? Increase the signal power, and that's what can harm cetaceans.
Other reason about active sonar harming cetaceans is not the "direct hit" of active sonar over them, but the sudden and unexpected loud sound, that can scare the animals when deep-diving, forcing them to interrupt the action, surfacing too fast and thus suffering decompression injuries.
Yes, I study cetaceans (and sometimes I even get paid for it).
Edit: of course I'm talking about peace-time periods.