London: A new research by scientists has determined that blue whales have had to increase their ‘singing’ to cope with noise pollution from ships.
Man-made noise such as ships’ engines has caused hearing loss in whales.
It has also caused other behavioural changes, including forcing the creatures to strand on beaches because they are unable to navigate.
The endangered blue whale uses sonar to navigate, locate prey, avoid predators and communicate.
However, in recent years, the increasing use of hi-tech sonar by ships, the noise of propellers, seismic surveys, sea-floor drilling, and low-frequency radio transmissions have made oceans noisier.
According to a report in the Telegraph, new research has shown that the whales are having to ‘chatter’ more often and for longer periods to communicate the location of prey and to mate.
Zoologist Lucia Di Iorio, of the University of Zurich, analysed the song of blue whales recorded by microphones during seismic explorations in the St Lawrence estuary off Canada’s north east coast over an eleven day period in August 2004.
“We found that blue whales called consistently more on seismic exploration days than on non-exploration days as well as during periods within a seismic survey day when the sparker was operating,” she said.
“This increase was observed for the discrete, audible calls that are emitted during social encounters and feeding,” she added.
The study provides the first evidence that blue whales change their calling behaviour when exposed to sounds from seismic surveys.
“This study suggests careful reconsideration of the potential behavioural impacts of even low source level seismic survey sounds on large whales. This is particularly relevant when the species is at high risk of extinction as is the blue whale,” added Dr Di Iorio.