Wednesday, 15 October 2014

A whale of a yarn about noise

The stress that noise can cause is known to most of us but what about the impact on whales? Not a subject of general discussion but made fascinating by Peter Brannen writing in that wonderful journal Aeon.
An example:
The march of commercial shipping had come to a halt as the world recoiled from the dreadful spectacle of crumbling skyscrapers and plane-shaped earthen scars. But underwater, the acoustic fog that had settled on the oceans for decades had lifted. The researchers found themselves in the middle of an unprecedented, if tragic, experiment. The melancholy days after 9/11 on the Bay of Fundy were a brief return to life in the pre-industrial oceans. As Parks’s team was recording the marine soundscape, Rosalind Rolland of the New England Aquarium was collecting faecal samples – floating whale poop – and measuring them for stress hormones. While Parks’s recordings testified to an ocean silenced by tragedy, Rolland found that the whales’ stress hormones had plummeted as well. The whales, it seemed, had finally relaxed.
Maybe it is the years I spent gazing at migrating whales in the sea below my home in Eden but these whale stories fascinate me. One other thing I learned from this beautifully offbeat article concerns the number of years a whale can live. Writing how hydrophones anchored to the continental slope off California have recorded a doubling of background noise in the ocean every two decades since the 1960s, Brannen notes:
For whales, whose lives can be measured in centuries, the dramatic change to the environment is one that could be covered in the biography of a single whale. As a testament to that longevity, in 2007, during a traditional whale hunt, indigenous Alaskans pulled a bowhead whale out of the water with a harpoon embedded in its blubber that had been made in New Bedford, Massachusetts, in the 1800s – a type of weapon that might have been familiar to Herman Melville.
‘It’s very likely that the individuals that were being recorded in 1956 were the same ones being recorded in 2000,’ Parks said. ‘Some of these whales were born before there were motorised vessels in the water at all.’
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