Whales 'stressed by ocean noise' (BBC)

[eppur_se_muova]

By Richard Black
Environment correspondent, BBC News

Noise from ships stresses whales nearby, researchers have shown.

Ships' propellers emit sound in the same frequency range that some whales use for communicating, and previous studies have shown the whales change their calling patterns in noisy places.

Now, researchers have measured stress hormones in whale faeces, and found they rose with the density of shipping.

The species studied in the Bay of Fundy in Canada, the North Atlantic right whale, is listed as endangered.
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Aquarium scientists have been studying them in the bay since 1980.

But the new study, reported in the Royal Society journal Proceedings B, came about through chance.
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more: http://www.bbc.co.uk/news/science-environment-16926005

[OKIsItJustMe]

1. New Study Finds Ship Noise Increases Stress in Right Whales

http://www.nicholas.duke.edu/news/new-study-finds-ship-noise-increases-stress-in-right-whales

[font face=Times, Times New Roman, Serif][font size=5]New Study Finds Ship Noise Increases Stress in Right Whales[/font]

Feb 08, 2012

[font size=4]DURHAM, NC – A new study, published today in the peer-reviewed Proceedings of the Royal Society B, offer the first evidence that exposure to low-frequency ship noise may be associated with chronic stress in whales.[/font]

[font size=3]The study, conducted in Canada’s Bay of Fundy, has implications for all baleen whales in areas with heavy ship traffic, and for the recovery of the endangered North Atlantic right whale population.

By analyzing underwater noise levels during a period of reduced ship traffic in the bay following the terrorist attacks of September 11, 2001, and the comparing those data with levels of stress-related hormone metabolites in the fecal samples of right whales before and after the attacks, the researchers were able to show a strong correlation.

“Essentially, the animals’ stress levels dropped when the underwater ship noises did,” says Douglas P. Nowacek, Repass-Rodgers University Associate Professor of Marine Conservation Technology and Electrical & Computer Engineering at Duke University.

“There was a six-decibel decrease in underwater noise in the bay following 9/11, with an especially significant reduction in the low-frequency ranges below 150 hertz. This correlated to reduced baseline levels of stress-related hormone metabolites in samples collected from whales later that fall,” he explains. “In subsequent years, ship traffic – and noise – were higher, along with the whale’s stress-hormone levels.”

…[/font][/font]

http://dx.doi.org/10.1098/rspb.2011.2429

[PamW]

2. What would you have us do?

Noise from ships stresses whales nearby, researchers have shown.

Ships' propellers emit sound in the same frequency range that some whales use for communicating, and previous studies have shown the whales change their calling patterns in noisy places.

Now, researchers have measured stress hormones in whale faeces, and found they rose with the density of shipping.
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What would you have us do? Dump a bunch of Zoloft in the ocean?

PamW

[OKIsItJustMe]

3. I suppose it would be impossible to engineer quieter ships…

http://www.noise-control.com/underwaternoise.php