'Whales can't even hear naval sonar' says Navy boffin
Enormous CT scanner used to probe spermwhale's noggin
A boffin funded by the US Navy has used a gigantic CT scanner, normally employed for inspecting space rockets, to X-ray the head of a whale. The results apparently indicate that naval sonars can't be the cause of whale beachings, as the mighty cetaceans are unable to hear the relevant frequencies.
The boffin in question is Dr Ted Cranford, whale expert at San Diego State University. He describes what he does in this way:
My work focuses primarily upon the functional morphology of biosonar, particularly sound generation and transmission, but also sound reception in toothed whales. I like to combine technological tools and traditional anatomic techniques to develop new or innovative methods to interrogate the structure/function complex.
One technological tool the doc has put to use is "a giant CT scanner, originally designed to inspect solid-fuel rocket motors".
"After scanning the head of a sperm whale, I subsequently reconstructed it using 3-D computer graphics tools to gain virtual access to the internal in situ anatomic geometry," reports Cranford, whose work is sponsored in part by the Office of Naval Research and the Chief of Naval Operations' Environmental Readiness Division.
Both these organisations have a deep interest in the details of whales' bio-sonar abilities, as it is frequently suggested by environmentalist groups that naval sonar confuses or distresses the mighty creatures - perhaps causing tragic beaching incidents. Similar claims are made with respect to dolphins.
But the ONR announced yesterday that Cranford's latest findings "suggest that mid-frequency active sonar sounds are largely filtered, or 'muffled', before reaching the animal’s ears. The findings also suggest that higher frequencies used by whales to hunt prey are heard at amplified levels without any dampening."
Mid-frequency active sonar has been in widespread naval use since World War II, though it has only been fingered by pro-whale activists as a cause of beaching in recent times - and beachings are rare, whereas sonar is used constantly in exercises. There have been protracted legal struggles between the US navy and environmental groups in the US courts over the issue, and similar allegations have been made regarding beachings in the UK.
Cranford's whale X-rays would seem to cast doubt on the protesters' assertions, at least in the case of whales - though he aims to check out dolphins too.
"These findings are promising," says the doc. "Our next step is to reproduce the study with a similar species for which hearing tests are available, such as the bottlenose dolphin. If we obtain like results, it will help to validate this new discovery."
Other recent research has backed up the idea that mid-frequency sonar could only harm dolphins' hearing in highly unusual circumstances.
This could be good news for whales and dolphins both, as it might mean that media and environmentalist attention will shift away from naval operations and away from beachings - a very minor problem for cetaceans - onto rather more serious problems. Commercial fishing, for instance, is thought to kill 1,000 marine mammals every day.
On the other hand, given the traditionally strong linkage between whale/dolphin activism and dislike of the military, possibly not. ®
Navy funded research finds Navy blameless,
also handsome and excellent lovers!
So what you're saying is...
a) We can't trust the Navy to run a proper study that may find them at fault
b) no-one else has done these studies
So what I'm picking up is that rather than place belief in possibly massaged studies we should put all of our faith in conjecture with not even a whitepaper to back it up? At least with the Navy studies they have to make the conclusion seem like it matches the data. with the greenpeace protesters we don't even get that level of integrety, mostly a "I said so, and you can trust me more than you can trust them." Which is a poor argument biased on flawed logic.
Please do not buy it!!!
First, Ted Cranford uses many untested assumtions in his work and it was brought up during recent conference in Quebec when he talked about beaked whales.
Second, recent study published by Canadian (!) scientists showed that all studies funded by NAVY largely do not find any harmfull effect of any Navy actions on marine mammals. Given that no other studies exist to refute these claims it just slides by default. Who on earth can use such scanner and not be funded by the Navy? C'mon! There is NO FUNDING available to refute any of these claims and that is why Navy funded studies cannot be trusted and should be ALWAYS taken with a grain of salt, these boffins have an agenda and this agenda is to prove to the public that NAVY does not harm any marine creatures.