"In cities, human lockdowns during the coronavirus pandemic have offered some respite to the natural world, with clear skies and the return of wildlife to waterways. Now evidence of a drop in underwater noise pollution has led experts to predict the crisis may also be good news for whales and other sea mammals.

Researchers examining real-time underwater sound signals from seabed observatories run by Ocean Networks Canada near the port of Vancouver found a significant drop in low-frequency sound associated with ships.

David Barclay, assistant professor of oceanography at Dalhousie University, the lead author of a paper reviewing the phenomena, examined sound power – a way of measuring “loudness” – in the 100 Hz range from two sites, one inland and one farther offshore. He found a significant drop in noise from both.

“Generally, we know underwater noise at this frequency has effects on marine mammals,” Barclay said."

Karen McVeigh reports for the Guardian April 27, 2020. [2]