NOISE from shipping traffic, wind farms and oil exploration was forcing whales near the UK to shout louder to make their mating calls heard, scientists have said.

Marine biologists studying whales in the seas around Britain found that their calls became 10 times louder over the past 50 years as they battled against sounds from the world's noisiest seas.

“The rumbling noises emitted by ships and marine installations have similar frequencies to those used by whales,” said Peter Tyack, a marine biologist at the Woods Hole Oceanographic Institution in Massachusetts.



“We found that whales are trying to adapt either by emitting much louder noises or by calling at higher frequencies. It’s like they’ve turned from a bass into a tenor."

Whales are renowned for their abilities to communicate using low-frequency noises.



The sound waves are hardly deadened at all by water, so larger species such as blue whales, which emit the lowest frequencies, might communicate over hundreds of miles.

Because the number of most large whale species is now estimated at less than five percent of their natural level, the ability to communicate over such distances could be vital to finding mates - but Dr Tyack and other scientists fear that human-induced noise risks drowning out or ruining the mating songs.

“The whales are not just getting louder. Their messages are getting simpler and repeated more often, just like a human forced to shout,” he said.



“It also means they spend more energy on communicating.”



Originally published as Mating whale calls compete with loud seas