Our oceans are becoming an ‘acoustic fog’ of noise, created by shipping, sonar and seismic survey equipment, and the impact on wildlife is serious, according to the Whale and Dolphin Conservation Society (WDCS).
Speaking at the UN Environment Programme (UNEP) Convention on Migratory Species, Mark Simmonds, science director of the WDCS, described the effect for marine animals as living in ‘a cacophony of sound’.
‘There is now evidence linking underwater noises with some major stranding of marine mammals, especially deep diving beaked whales,’ he said. ‘However, it also appears that other species may also be affected.’
Low frequency underwater noise has doubled every 10 years since 1950, and the global shipping fl eet is expected to double in size by 2025. New sonar equipment generates sound levels well in excess of those created on land by a jet aircraft taking off, and some seismic survey equipment can be heard 3,000 km from its point of origin.
But in an added twist, the situation is set to worsen as a result of climate change. As CO2 levels rise and the ocean becomes increasingly acidic, the change in sea water chemistry means that low frequency noise may travel even further. Scientists at the Monterey Bay Aquarium Research Institute in the US believe that the ocean may have already becoming 10 per cent less absorbent of low frequency sound waves than it was before the industrial revolution.
If acidity increases in line with climate models, underwater noise pollution could travel 70 per cent further in 2050 than it does today.
The International Fund for Animal Welfare (IFAW) is calling for sonar manufacturers, ship builders, governments and the military to install and use quieter marine technologies and make other efforts to reduce ocean noise levels.
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