Man-made noises cause ocean giants to move away from feeding spots
July 2013. Some blue whales off the coast of California change their behaviour when exposed to the sort of underwater sounds used during U.S. military exercises. The whales may alter diving behaviour or temporarily avoid important feeding areas, according to new research.
The Southern California Behavioural Response Study exposed tagged blue whales in the California Bight to simulated mid-frequency (3.5-4 kHz) sonar sounds significantly less intense than the military uses.
Modifying diving bevaviour
"Whales clearly respond in some conditions by modifying diving behaviour and temporarily avoiding areas where sounds were produced," said lead author Jeremy Goldbogen of Cascadia Research. "But overall the responses are complex and depend on a number of interacting factors," including whether the whales were feeding deep, shallow or not at all.
Special tags
The scientists tagged the whales with non-invasive suction cups, which recorded acoustic data and high-resolution movements as the animals were exposed to the controlled sounds.
"The tag technology we use offers a unique glimpse into the underwater behaviour of whales that otherwise would not be possible," said Ari Friedlaender, a research scientist at the Duke Marine Laboratory.
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