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Powerful Sonar Causes Deafness In Dolphins
Hugh Pickens writes "Mass strandings of dolphins and whales could be caused because the animals are rendered temporarily deaf by military sonar, experiments have shown. Tests on a captive dolphin have demonstrated that hearing can be lost for up to 40 minutes on exposure to sonar and may explain several strandings of dolphins and whales in the past decade. Most strandings are still thought to be natural events, but the tests strengthen fears that exercises by naval vessels equipped with sonar are responsible for at least some of them. For example, in the Bahamas in March, 2000, 16 Cuvier's beaked whales and Blainville's beaked whales and a spotted dolphin beached during a US navy exercise in which sonar was used intensively for 16 hours (PDF). 'The big question is what causes them to strand,' says Dr. Aran Mooney, of the University of Hawaii. 'What we are looking at are animals whose primary sense is hearing, like ours is seeing. Their ears are the most sensitive organ they have.' In the experiment, scientists fitted a harmless suction cup to the dolphin's head, with a sensor attached that monitored the animal's brainwaves, and when the pings reached 203 decibels and were repeated, the neurological data showed the mammal had become deaf, for its brain no longer responded to sound. 'We definitely showed that there are physiological and some behavioral effects [from repeated, loud sonar], but to extrapolate that into the wild, we don't really know,' said Mooney."
Loud noises tear the cilia in your cochlea out by the roots. In humans, and, as far as I know, other higher mammals, they don't grow back (Can someone who knows confirm that this is true in dolphins as well?).
So the word "temporary" might make this sound less bad than it is: Our sonar may only temporarily cause total deafness, but I suspect it permanently degrades hearing.
Sucks to be a dolphin. Reminds me of Douglas Adams' sympathy for whales, whose songs no longer can be heard across the ocean. (I think Douglas talked about this in Last Chance to See.)
you do realize that 99%+ of the time, these terrible nuclear submarines don't even use ANY form of sonar other than underwater microphones don't you?
To a similar (though not as high degree) neither do surface ships.
I didnt think so.
yet another example of a slashtard talking out of their ass with absolutely NO idea what they are talking about.
And yes, I did happen to serve on one of these terrible nuclear submarines.
and in the case of missle subs, it's probably closer to three nines or more.
ssbn subs are holes in the water that strive to make absolutely no noise.
you can hear the original sound wave a lot further off than you can hear the return echo which is always weaker.
and that's before you even throw in the effect of temperature gradients and convergence zones.
another thing to ponder is what was the frequency used?
and does this matter.
the reason i say this is that MOST sonar is low frequency or extremely low frequency, with the exception being high frequency sonar used to search for underwater mines and to penetrate ice fields.
of course, why mention these type things as they will just muddy the waters and potentially invalidate the test.........
(I said potentially, not that they do, i have no idea and based on the report, neither does anyone else)
I spent 7 years in the Navy, and we could hear the sonars be tested in port on ships several piers down. The Navy need better listening equipment, not louder speakers. Whales communicate for several hundred miles with whatever their voice boxes can make, and the receiver can hear it and respond. Nature has done it, why can't we?
> Whales communicate for several hundred miles
That's a pretty lowball estimate (src):
We now have evidence that they are communicating with each other over thousands of miles of ocean. Singing is part of their social system and community.
Your brain is not a computer.