Sound of the sea: Underwater noise pollution from ships plummets during the coronavirus lockdown offering respite for ‘stressed’ whales and other marine life
- The COVID-19 crisis has seen a reduction in shipping traffic around the world
- Experts recording sound off of the coast of Canada have seen noise levels drop
- Researchers are now racing to study how these changes are affecting marine life
- Previous work found that whales alter their songs in response to noise from ships
- Here’s how to help people impacted by Covid-19
Levels of underwater noise pollution from ships have plummeted during the coronavirus lockdown, offering a respite for whales and other marine life.
Researchers studying the changes off of the coast of Canada have called the reduction in shipping something akin to a ‘giant human experiment’.
Around the world, biologists are keen to record the effect that the ambient noise reduction has on life within the oceans.
Previous studies have indicated that noise pollution underwater forces whales to change how the sing and also causes them to become stressed.
The COVID-19 crisis has seen a significant reduction in vehicle, air and ocean-going traffic — with corresponding reductions in both air and noise pollution.
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Levels of underwater noise pollution from ships have plummeted during the coronavirus lockdown, offering a respite for whales and other marine life
Oceanographer David Barclay of Canada’s Dalhousie University and colleagues have been analysing underwater sound recordings taken at two sites near the port of Vancouver — finding a significant drop in low-frequency shipping noise.
‘Generally, we know underwater noise at this frequency has effects on marine mammals,’ Professor Barclay told the Guardian.
At one site, he added, ‘there has been a consistent drop in noise since 1 January, which has amounted to a change of four or five decibels in the period up to 1 April.’
During this time, the port has seen a drop of around 20 per cent in exports and imports, economic data has revealed.
At the second site, meanwhile — located in deeper waters, at a depth of around 9,843 feet (3,000 metres), and around 37 miles (60 kilometres) from the nearest shipping lanes — ambient weekly sound levels fell by around 1.5 decibels.
‘This gives us an idea of the scale over which this reduction in noise can be observed,’ Professor Barclay told the Guardian.
The last time that the oceans fell quiet was in the wake of the terrorist attacks of 9/11, when a reduction in shipping allowed experts to determine that ship noise is connected to chronic stress in baleen whales
‘We are facing a moment of truth,’ marine acoustician Michelle Fournet of Cornell University — who studies humpback whales off of Alaska — told the Guardian.
‘We have an opportunity to listen — and that opportunity to listen will not appear again in our lifetime.’
The last time that the oceans fell quiet was in the wake of the terrorist attacks of 9/11, when a reduction in shipping allowed experts to determine that ship noise is connected to chronic stress in baleen whales.
In the present, Dr Fournet added, ‘we have a generation of humpbacks that have never known a quiet ocean.’
Were it not for the COVID-19 crisis, the present time of the year would be the beginning of the cruise ship season in south-eastern Alaska, with the liners calling at Vancouver before sailing on to the north.
‘What we know about whales in south-east Alaska is that when it gets noisy they call less, and when boats go by they call less,’ said Fournet.
‘I expect what we might see is an opportunity for whales to have more conversation and to have more complex conversation.’