Underwater Sonar Linked To Whale Deaths 187
An anonymous reader writes "A group of scientists have confirmed a link between the sonar used by Exxon Mobil to map the ocean floor for oil and the death of melon-headed whales. From the article: 'A spokesman for ExxonMobil said the company disagrees with the findings. "ExxonMobil believes the panel's finding about the multi-beam echo sounder is unjustified due to the lack of certainty of information and observations recorded during the response efforts in 2008," spokesman Patrick McGinn told AFP in an email. He added that observers employed by the Madagascar government and the oil giant "were on board the vessel and did not observe any whales in the area."'"
Re:Anti-oil propaganda (Score:4, Informative)
Wrong.
http://www.sibleyguides.com/conservation/causes-of-bird-mortality/ [sibleyguides.com]
http://science.howstuffworks.com/environmental/green-science/wind-turbine-kill-birds.htm [howstuffworks.com]
No! Not At All. (Score:5, Informative)
If you read the actual report [iwc.int], you'll see these statements:
"There is no uneqiovocal and easily identifiable single cause of this event,"
"This is the first known such marine mammal mass stranding event closely associated with relatively high-frequency mapping sonar systems,"
"MBES systems (similar) to the 12 kHz source used in this case are in fact commonly used in hydrographic surveys around the world over large areas without such events being previously documented."
"There may well be a very low probability that the operation of such sources will induce marine mammal strandings,"
Re:That's it (Score:5, Informative)
The reason for the doubt is that melon-headed whales beach themselves anyway with surprising frequency.
Re:That's it (Score:4, Informative)
The five-member independent scientific review panel said the vessel's MBES was "the most plausible and likely behavioral trigger for the animals initially entering the lagoon system."
There have been reports of damaged hearing organs in other cases, so you are probably thinking about news that you read about Florida. In this case, the article has no mention of ear damage.
Sorry, but you are wrong... (Score:2, Informative)
As much as you like to pretend wind energy has no cost, it very much in fact does kill birds, including eagles [huffingtonpost.com].
The problem for you and your fellow revisionists is that people can actually see wind farms killing birds. So you can bring up all the studies you like but it doesn't change what actually happens in real life.
Re:Cognitive Errors, Courtesy Exxon (Score:2, Informative)
Just to be clear, you are saying this entire section is wrong?
http://en.wikipedia.org/wiki/Echo_sounding#Hydrography [wikipedia.org]
Although I couldn't find anything definitive on the hearing ranges for this type of whale, it is reasonable that that can hear up to 50 or 60 kHx:
http://www.hmmc.org/MarMammSpp/Peponcephala/Peponcephala.html [hmmc.org]
Beluga whales can hear double that at the high end, and both are well within the range for some of the lower frequencies used for multibeam sounders.
Re:Cognitive Errors, Courtesy Exxon (Score:3, Informative)
Some reference (Score:5, Informative)
Typical sonars are about 160-200 dB re 1 uPa 1 m. The US Navy sonar which caused all the controversy years ago was 226 dB if I remember right. Yes these are loud, but remember it's measured at 1 meter. At 100 meters, it will have attenuated by -40 dB.
Yes those are loud, but I'm a little skeptical of all these claims of sonar harming whales because as most of you know, whales and dolphins use sonar themselves. It's typically 170-190 dB re 1 uPa 1m, with peaks over 220 dB [google.com]. They're at different frequencies though (100+ kHz for dolphins, 10-25 kHz for most depth finders, 3 kHz for the Navy sonar), and higher frequencies attenuate more quickly in the water.
Re:Cognitive Errors, Courtesy Exxon (Score:4, Informative)
Look, as somebody who actually works in this industry
... And whose identity is "Anonymous"
, multibeam sounders operate on very high frequencies, way over what whales can perceive.
And yet, I can take away your hearing by emitting ultrasound if it's powerful enough. You won't hear yourself going deaf, you'll just go deaf. Actually, I can even kill you [wikipedia.org] with exposure of 180dB of ultrasound. But, working (anonymously) in the industry, you'd know that frequency is only part of the equation.
What's hilarious here is that the Slashdot circle-jerkers are already screaming EXXON...BAAAAD!
Statements like these definately add to your credibility. By making juvenile sexual jokes, it's immediately obvious to everyone that this is a man who makes six figures in the field of Oceanography.
But do you know what kind of sonar does make whales' ears bleed?
Yes: The very loud kind. Just like any other animal's ears. In fact, whale's ears are more suseptible to damage due to high decibel emissions than humans because in the human ear, air waves hit a membrane behind which there is a liquid-filled area, thus the energy of the wave can be dissipated; Pressure waves travelling through air are much less powerful than underwater, because of the density of the medium. Whales, unfortunately, have inner ears filled with the same liquid is its surrounding environment, and at the same pressure... meaning there is no transitive barrier to protect them.
The big fucking' spherical and cylindrical arrays you find in the tips of the bulbous dicks of ships and submarines.
Well, without knowing which ship was involved in a 6 year old incident, it's impossible to know whether any phallic-shaped devices were mounted to the ship. However, while lacking your literary ability in the many uses of the word 'fuck', an independent science team, perhaps with less impressive credentials than yours, found the ships' activities were the likely cause [huffingtonpost.com] of the sudden displacement and eventual death of the whales. Oh, and the names of the members of that scientific team were the International Whaling Commission, the US Marine Mammal Commission, the US National Oceanic and Atmospheric Administration, the US Bureau of Ocean Energy Management, ExxonMobil Exploration and Production (Northern Madagascar) Ltd, the International Fund for Animal Welfare, the Wildlife Conservation Society and the Government of Madagascar. They all think you're full of crap, but what would over a hundred scientists know compared to someone who swears like a sailor anonymously on slashdot?
Have you even seen a fucking multibeam? The transducer array is roughly the size of a shoebox.
You must have very big feet then [noaa.gov]. That's a picture of the NOAA's multibeam echosounder, an ER60 [kongsberg.com]. It is a low-power model, and in this case is being used to track the migratory movements of fish, and is of limited range. The kind that several sources have indicated were used by ExxonMobile inject high pressure air into the water; These are considerably larger, and more powerful, than these systems, which modulate a diaphram. It's the difference between your laptop's speakers, and a pneumatically-driven organ like those seen at older churches. Needless to say, the organ is much louder.
Idiots. I'm surrounded by goddamn idiots!
Yeah... I know this feeling well. Look at how often I get downmodded for providing factual and relevant commentary, instead of simp
Re:Sorry, but you are wrong... (Score:5, Informative)
There are now approx' 200,000 bald eagles.
"Only nine bald eagle collisions with turbine blades have been recorded nationally" Ever?
So, what is your point?
"Of 1,428 individuals from across the range necropsied by National Wildlife Health Center from 1963 to 1984, 329 (23%) eagles died from trauma, primarily impact with wires and vehicles; 309 (22%) died from gunshot; 158 (11%) died from poisoning; 130 (9%) died from electrocution; 68 (5%) died from trapping; 110 (8%) from emaciation; and 31 (2%) from disease; cause of death was undetermined in 293 (20%) of cases."
Windmills are the least of their problems.
Man-made structure/technology Associated bird deaths per year (U.S.) :-
Feral and domestic cats : Hundreds of millions [source: AWEA]
Power lines : 130 million -- 174 million [source: AWEA]
Windows (residential and commercial) : 100 million -- 1 billion [source: TreeHugger]
Pesticides : 70 million [source: AWEA]
Automobiles : 60 million -- 80 million [source: AWEA]
Lighted communication towers : 40 million -- 50 million [source: AWEA]
Wind turbines : 10,000 -- 40,000 [source: ABC]
Re:Exxon's Response (Score:5, Informative)
As a shipboard oceanographic technician... (Score:5, Informative)
I spent three years sailing on the Scripps Institution of Oceanography research vessels, mostly the Revelle, and the Melville. One of my primary responsibilities was operating the multibeam sonar [wikipedia.org] and other acoustic instruments. Working on ship is interesting, it's sort of like college, where you live in one small floating building housing the dorms, labs, cafeteria, and plant, with 40 people, except you cannot leave the building for 50 days at a stretch. It's like being on a reality show living and working with scientists of all types, and some other colorful characters.
None of the 50 or so marine biologists that I ever sailed with ever had the slightest concern about the multibeam's impact on marine life. And belive me they were very interested in sonar's effects on marine mammals. Anytime we would perform SEISMIC survey ops [wikipedia.org] we were required by law to have a marine mammal observer on watch. If they sighted any whales in the area, we shut down the air guns. In the old days they used sticks of dynamite, now they use 3000psi air guns. Loud.
Bear in mind our ship cost up to $50,000 per DAY to operate. And that's just for the ship, crew, and technicians, not the scientists and who or what ever they bring. Commercial vessels probably cost much more to operate; the greatest cost is diesel; ships burn thousands of gallons per day; we bought ours from the Navy. But the MMO's were professional scientists and took their jobs seriously and we respected them and I would call them my friends. The idea that any of the other acoustic instruments could harm marine mammels was never broached. Another time I sailed with a large group of marine biologists who were basically pinging whales with high powered sonar to see what would happen because they were concerned with high powered sonars effects on whales. They never brought up any of the ships other acoustic instruments.
It's possible that MB has an effect. You could hear our MB all over the ship. We ran a Simrad EM-120 [google.com] at 12khz, which I can hear pretty well. It sounded like a really loud bird chirping. And sometimes you could even hear the tinkling echos off the seabed. I can see how it MIGHT annoy whales. And I bet the commercial ships run a much higher-power sonar. They drag like 12 airguns when we drag one or two. I think a lot of it also depends on where you're operating. Most of the ocean is surprisingly empty and devoid of higher life forms. Perhaps greater percautions are needed close to whale populations. It's just surprising because as a member of the oceanographic community I for one was not aware that this issue was even on the radar (no pun intended).
MB sonar is generally a "good thing". We can only get very coarse bathymetry via satellite. MB is necessary to map the seabed in any detail and seabed maps are critical to earth science. I just hope this doesn't turn into some sort of sonar hysteria where we are unecessarily restricting good scence based on bad science.
Re:As a shipboard oceanographic technician... (Score:2, Informative)
Sigh. The irony continues. If you read the original report, air guns were NOT involved. The popular press has confused discussion of the echosounder survey with a seismic survey in the area, which was several days *after* the stranding and therefore eliminated as a possible cause. Both of them are discussed in the report. Only one of them is relevant because it was occurring before the stranding.
Re:That's it (Score:4, Informative)
We can only use overwater sonar from now on.
It's called a Sodar [wikipedia.org], and I've written software for them.