The Irish Times view on the sound of the oceans: quiet please
Sound pollution is causing as much damage to marine life as overfishing, pollution and the climate crisis
Sound can travel thousands of miles and link animals across ocean vastnesses and in darkness, and many species are impeccably adapted to detect and communicate with sound. Photograph: Padraig Whooley/ CWW
A man-made cacophony reverberates across our ocean floors – the roar of ships’ propellers and engines, seismic tests, piles driven deep, dynamite fishing, the rumble of trawls on the seabed, platforms drilling, and even speedboats. Sound pollution is causing as much damage to marine life as overfishing, pollution and the climate crisis, scientists say. But is being dangerously overlooked.
On the Great Barrier Reef alone noise from motorboats has led to double the marine life mortality from predators. Since 1970 the overall number of marine animals has declined by about half.
An international study in Science collates the largest synthesis yet of evidence on the effects of oceanic noise pollution. Its conclusion, that humans have made the ocean an unbearably noisy place for marine life, drowning out natural soundscapes and threatening species, raising stress levels or forcing their displacement. Species affected include those as simple as zooplankton and jellyfish.
Sound can travel thousands of miles and link animals across ocean vastnesses and in darkness, and many species are impeccably adapted to detect and communicate with sound. Sealife uses sound to catch prey, navigate, defend territory and attract mates, as well as find homes and warn of attack.
Dolphins call one another by unique names. Toadfish hum. Cod honks to coordinate spawning. Bearded seals trill. Humpback whale songs can resemble a violinist’s melodies. Sperm whales, dolphins and porpoises use sonar to echolocate prey. Shrimps produce a “snap” sound to stun prey. Drowning out such sounds is transforming entire ecosystems.
There are alternatives. Propeller redesign can significantly reduce noise. Half of shipping noise comes from just 15 per cent of vessels, while one study shows that cutting the speeds of noisy boats in the Mediterranean from 15.6 to 13.8 knots cut noise by half. Electric motors are another possiblity. Seabed seismic testing can replace sending noise waves through the whole water column.