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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."
Wow. I think if you expose me to a 203 decibel sonar, it's not just my ears that would go poof.
Experiments like these are like putting people next to a jet engine to see if their hearing gets damaged. I am no PETA freak, but putting 200+ decibels is bound to do permanent damage. I know they said it is temporary, but that might be like my "temporary" hearing loss from the Boston show a few months back. Yes, I could hear fine afterward* but I wonder what incremental loss I might have had from all that loudness.
*I have higher pitch loss that apparently came from shooting a lot many years ago without hearing protection.
This post brought to you by your friendly neighborhood MBA.
I can't believe the military is still playing dumb and pretending they aren't aware their sonars are affecting marine life.
Must be nice to be in a permanent state of denial.
You don't need to actually make dolphins deaf to know if they will be deaf! Not only is that cruel, it's unnecessary.
It's common knowledge that exposure to 200+ decibels will make anything deaf. And this Dr. Mooney is an idiot.
If it makes them deaf in a lab, it fucking works outside the lab!
They're using their grammar skills there.
My wife is a wildlife conservation researcher, and specifically works with animals in the Delphinidae family (which include dolphins). There's a lot of stuff she, and others, have to - must - verify, even if it seems to be a "wellduh."
The alternative would be that science just thinks correlation = causation. Is that what we want? "Well, Navy ships used sonar, and these whales stranded themselves...must be related. Case closed." Instead, someone did actual science showing that sonar causes real deafness in these animals. And someone wants to harsh that?
I say instead that there should be a tag, "abouttimetheyverified"
Classic Greek authors tell us that in the ancient Greece, dolphins and whales were already found stranded on the shore. This was a windfall for the locals, who were not eating meat very often. They saw it as a divine gift and thanked Poseidon for it.
So considering that the Greek galleys didn't use sonar, we need to stop barking at the wrong tree and find the cause of this phenomenon. My money is on a parasitic disease that affects the brain.
Fantasy: http://ferrisfantasy.blogspot.com/
what do you think?
the military probably uses less sonar in day to day operations than the rest of the scientific community does.
after all, how can you plot out that wreck without side scanning sonar?
how can you map those undersea ridges and trenches without using some sort of down firing sonar?
the truth of the matter is, sonar as used by the military is mostly a passive system.
it's kinda like sitting out in the woods while hunting. you don't go around making a lot of noise because it can be heard further away than you can hear the animals you're hunting.
which, depending on the animal, either allows them to flee undetected or allows them to hone in on your location and find you and kill you.
it's the same reason military jets don't just fly around with their search radar on, because it can be detected a long way off, and with some simple geometry and two reception points, they know where the jet now is.....
and then they can use a less detectable method to eliminate that jet.
like say an infra-red heat seeking missle instead of one that requires radar guidance.
Random unstructured Tourette's-style musings rarely translate well in a written medium (even on Slashdot).
There's no doubt something valuable in your post, but unless you write out your thoughts in a coherent form, we won't know what it is.
So 200 sounds extreme
Well yeah, it is. Comparing it to 185 is pointless since decibels are measured on a logarithmic scale.
http://www.underwatertimes.com/news.php?article_id=48723961015
That study used fish. Fish are not mammals but dolphins, porpoises, and whales are.
Not that I personally believe it don't effect them, though we may not know how to tell.
Marine mammals are shown to hemorrhage from sonar.
Falcon
Should there be a Law?