They look playful but a dolphin has a happy face regardless of what they may be feeling. Research strongly suggests marine mammals are highly susceptible to engine noise and beaching may well be down to interference with their sonar signals. Plenty of articles out there but this one from
the Guardian has credible information...
Today, ocean waters are a tumult of engine noise, sonar and seismic blasts. Sediments from human activities on land cloud the water. Industrial chemicals befuddle the sense of smell of aquatic animals. We are severing the sensory links that gave the world its animal diversity. Whales cannot hear the echolocating pulses that locate their prey, breeding fish cannot find one another amid the noise and turbidity, and the social connections among crustaceans are weakened as their chemical messages and sonic thrums are lost in a haze of human pollution.
In air, we hear only a low groan from passing vessels. The sound is mostly transmitted down, below the waves, and the aerial portion is quickly dissipated. Under the surface, the sonic violence of powered boats travels fast and far through the pulse and heave of water molecules. These movements flow directly into aquatic living beings. Sound in air mostly bounces off terrestrial animals, reflected back by the uncooperative border of air to skin. Our middle-ear bones and eardrum are specifically designed to overcome this barrier, gathering aerial sound and delivering it to the aquatic medium of the inner ear. Sound, for us, is focused mostly on a few organs in our heads. But aquatic animals are immersed in sound. Sound flows almost unimpeded from watery surrounds to watery innards. “Hearing” is a full-body experience.
Since 2017, the Port of Vancouver has enacted a
voluntary slowdown of shipping traffic headed through the Haro Strait. For 30 nautical miles, large vessels slow, adding about 20 minutes to the ships’ voyages. Ship noise increases with speed, and so dialling back the throttle lessens the cacophony in a place where the southern resident whales often feed. More than 80% of vessels have complied with the project.
I'm not sure the UK has any policy in regard to protecting marine life like that but it's something that should be taken into consideration as shipping in the Channel increases year on year.
webapp.navionics.com
