Powerful Sonar Causes Deafness In Dolphins 323
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."
203 decibels? (Score:5, Insightful)
Experiments like these... (Score:5, Insightful)
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.
Retarded (Score:1, Insightful)
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 dont' need to make dolphins deaf. (Score:4, Insightful)
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!
Re:Experiments like these... (Score:2, Insightful)
Anything that is used for prolonged periods (16 hours) is going to have detrimental effects on the mammals' methods of navigation. Why is it such a terrible crime that the Navy consider what damage it does to its surroundings? Not implying you, it's just their stance is TeRRorisM! our actions can't be hindered.
Re:Experiments like these... (Score:2, Insightful)
I am no PETA freak, but putting 200+ decibels is bound to do permanent damage.
Perhaps the experiment was inhumane. Hypocrisy demonstrated. Point taken.
That does not change the conclusion: military exercises that include sonar cause injury to advanced marine life.
The ramifications should be obvious, but just in case they aren't...
Harming endangered species is illegal, and for good reason...their extinction could have unwanted ecological consequences and will certainly have unwanted sociological consequences for us.
Harming non-endangered, but advanced, animals should be avoided when possible (for moral reasons and also the sociological consequences...nobody wants a PETA riot).
Re:Retarded (Score:4, Insightful)
The reality is that they don't particularly care. They have to, for purposes of public relations, act like there's no problem, like what they're doing is perfectly fine, but the reality is that they could care less if every cetacean in the ocean died tomorrow.
to the "wellduh" taggers (Score:5, Insightful)
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"
Re:Experiments like these... (Score:5, Insightful)
I am no PETA freak, but putting 200+ decibels is bound to do permanent damage.
The document linked on the Bahamas stranding says that source levels were 223 - 235 dB and levels were less than 180 dB at 300 m horizontally and 200 m vertically, so unless the dolphins were EXTREMELY close to the ships when the sonar was turned on the odds of even temporary deafness due to the use of sonar in the wild are quite low. Remember: a 40 dB difference in signal is a factor of 10,000 in amplitude of the pressure wave, so unless the dolphins were within a few meters of the source they would be very unlikely to get anything close to 200 dB.
This is a bit like dropping a 10 kg mass on a person and noticing it causes serious damage, and then arguing that you can say something about the effects of dropping 0.001 kg masses on people based on the 10 kg data.
That's not to say that it isn't plausible that dolphin sonar can be screwed up by powerful sonar, but this experiment just doesn't seem relevant to the question.
Re:Experiments like these... (Score:4, Insightful)
Dolphin stranding in ancient Greece (Score:4, Insightful)
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 [caltech.edu].
Re:Only military? (Score:3, Insightful)
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.
Re:Experiments like these... (Score:5, Insightful)
180 db is still extremely strong. Now, compound that with the fact that the Submarines are moving, pinging and that Dolphins are curious anmials and like to follow ships... and I think you will find that the chances for Dolphins being near one of these ships greatly increased.
Also, I understand the need to defend the human race, military and blowing stuff up, but ask any blind person how much noise pollution hurts and then comment again.
Re:you dont' need to make dolphins deaf. (Score:4, Insightful)
This study represents a "nail in the coffin" type of study, where it is now known unequivocally that 203 decibels will harm wildlife. To logical people, this is what's known as "proof". Knowing this, you can now measure the sound level of the Navy's sonar tests and if it's above 203 decibels, you have direct evidence that the Navy IS harming marine animals. It sounds silly and trivial, but this is how logic works sometimes, you have to prove something beyond a shadow of a doubt, and past a shadow if you want to change society.
Re:Disarmament (Score:1, Insightful)
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.
Re:203 decibels? (Score:5, Insightful)
Couldn't the sonar be replaced by something less damaging? I guess water muffles radio waves, so a water radar is not a good idea. Maybe a very low frequency radar?
The problem with that theory is that you'd need such a low frequency that your wavelength would be hundreds to thousands of miles. The antenna requirements alone would make such a system impractical on a mobile basis. Some of the antennas used for ELF submarine communications systems were up to 20 miles long.
Unless you can change the laws of physics I'm afraid we'll be stuck using sonar for the foreseeable feature. If you accept that then you have to accept the fact that the Navy needs to practice with it before they need it in an actual shooting war. Sucks that it apparently harms marine life but what can you do?
Re:203 decibels? (Score:5, Insightful)
Sucks that it apparently harms marine life but what can you do?
Stop human beings from killing each other over nothing, obviating the need for submarines and therefore sonar?
I like to start small and work up.
Re:Dolphin stranding in ancient Greece (Score:5, Insightful)
Re:Experiments like these... (Score:4, Insightful)
Why is it such a terrible crime that the Navy consider what damage it does to its surroundings?
What makes you think they don't already or that the damage to those surroundings is more important than our ability to keep the sea lanes open in the next shooting war?
Re:203 decibels? (Score:5, Insightful)
Stop human beings from killing each other over nothing, obviating the need for submarines and therefore sonar?
Good luck with that.
Re:Experiments like these... (Score:5, Insightful)
I think you're both essentially right.
If the dolphins were further away, the sonar would be far less damaging, but it could still interefere with their navigation.
It's also very possible that the dolphins were following the ships and exposed to deafening decibel ranges.
This study (like most studies) is just a stepping stone to narrow down criteria/goals for other studies...we need to A) Determine the effect of lesser decibel levels and B) Gather real observational data on how often dolphins and other marine life venture very near to naval vessels.
Ultimately results of these studies should just regulate situations on when active sonar is used, where you can train with it, etc, because active sonar is necessary until something better is developed. Despite the very slim chances of nuclear war, as tragic as it is, I'm willing to sacrifice a few hundred sea critters (I wold hope it's a much smaller number though) just to know that we can effectively track and destroy nuclear missile subs (as well as the many other uses for sonar). That's just my opinion and you can call me a barbarian for it if you like.
Re:Experiments like these... (Score:3, Insightful)
A couple of things: submarines don't use active sonar if they can possibly help it - active sonar is very helpful in locating someone, but it's even more helpful in announcing your presence to everyone out to well beyond the range the active sonar can detect someone.
Dolphins don't spend a lot of time down where the subs routinely travel.
And a dolphin might very well be curious about a ship, and head toward it. But unless they're dumb as posts, they'll turn away before the sonar reaches the "deafening" level.
Re:203 decibels? (Score:3, Insightful)
Or passive sonar. Active sonar (pinging) is like standing in a dark field with a huge omnidirectional beacon. You'll probably see someone else standing around by the light reflected off them, but they'll certainly see you first.
Passive sonar is like hiding in a dark corner of the field watching everyone else stumbling around with flashlights. Their lights may not be very bright (i.e., the ships' engines and hulls may be very quiet), but they always make some noise, which your super-sensitive passive sonar will pick up.
Re:Experiments like these... (Score:4, Insightful)
Because the design purpose of a Navy is to kill people and break things?
Or are you really suggesting that they should spend more time finding ecologically friendly ways to sink ships and kill people?
Re:Temporary damage and singing under water... (Score:2, Insightful)
So 200 sounds extreme
Well yeah, it is. Comparing it to 185 is pointless since decibels are measured on a logarithmic scale.
Re:203 decibels? (Score:4, Insightful)
If they issued the ping day and night every minute or so, the dolphins would maybe understand to stay away from the dangerous areas.
So would our enemies.
Re:Experiments like these... (Score:2, Insightful)
Becasue a species must watch out for themselves first.
I'd personally kill every Dolphin myself if it would save a human life.
You're kidding, right? Or are you really that sick and disgusting?
Re:Experiments like these... (Score:4, Insightful)
Re:Dolphin stranding in ancient Greece (Score:3, Insightful)
Remember: this is /.
So please stop making complete and utter sense.
But continue blaming Windows.
And it's bark "UP" the wrong tree, not "AT", OP.
Contradicition: (Score:3, Insightful)
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 [oceanmammalinst.com] are shown to hemorrhage from sonar.
Falcon
Re:Experiments like these... (Score:2, Insightful)