Whales, squid, fish, crabs and shellfish are all suffering from the rising din being made by propellers, engines and subsea drilling, prompting demands for quieter ships and the introduction of “quiet areas” in the seas.
Hundreds of marine biologists from across the world are gathering this weekend in Glasgow for the International Marine Conservation Congress, organised by the Society for Conservation Biology. They will hear mounting evidence of the widespread damage to animals being done by underwater noise.
Over the last half-century low frequency noise in the oceans has increased by at least 20 decibels. Most of the noise comes from ships, which are carrying three times the weight of cargo they did in 1970, amounting to more than 80 per cent of all the world’s freight transport.
A series of expert studies from three continents have shown a large variety of ways in which noise can harm wildlife. Squid and octopus were found to suffer “massive acoustic trauma” destroying hair cells vital for balance and orientation.
Scallop larvae were delayed and deformed by noise, the internal organs and ovaries of snow crabs were bruised and eels showed signs of stress. In another study, noise killed the eggs and young of sea hares.
“The oceans already face a multitude of threats,” she added. “By adding yet another stressor like human-generated noise, the consequences could be severe.” It was also a problem that could be addressed “relatively easily” by building quieter engines, she argued.
Matt Wale, a researcher at the University of Bristol and then Edinburgh Napier University, has discovered that playing ship noise to shore crabs affects the way they behave. It can distract them from food, delay them hiding from predators and make them breath faster, resulting in “elevated risks of starvation and predation”.
A study in Nova Scotia’s Bay of Fundy by the New England Aquarium in Boston, US, concluded that North Atlantic right whales suffered “chronic stress” from ship noise. Another study by the Pennsylvania State University, US, showed that right whales have to call louder as ocean noise levels rise.
Dr Rob Williams, a Canadian marine scientist who recently completed research at University of St Andrews, discovered that in busy shipping lanes whales could be deprived of 90 per cent of their opportunities to communicate with members of their family. Killer whales also reduced the time they spend feeding by up to 25 per cent when boats were around.
“We know that noise affects communication, hunting success and behaviour of individual animals,” he said. “That could affect the whales' ability to have or nurse calves.”
He urged the adoption of “quiet marine protected areas” and economic incentives to build quieter ships using technologies developed by navies. “Preliminary calculations suggest that the noisiest ten per cent of ships produce 80-90 per cent of the noise,” he said. “We don't need to ask everyone to quiet their ships, just the noisiest.”
Lang Banks, the director of WWF Scotland, pointed out that noise pollution could cause long-term damage to marine species. “To address the potential threat we need to see quieter ships as well as action to reduce noise levels from shipping in especially critical habitats,” he said.
The UK Chamber of Shipping welcomed accredited scientific research that helped understand the problem. “The impact of noise from shipping on marine life is a highly complex, emotive and much misunderstood subject,” said the chamber’s chief executive, Guy Platten.
“Industry, government and environmental groups recognise that as old ships are decommissioned, and new ships come into service, significant progress will be made in reducing the noise impacts from shipping.”
UK Oil and Gas, which represents the offshore industry, described research as “inconclusive” and did not sound keen on quiet zones. “The first priority is to better understand the various sources and cumulative levels of sound energy the industry produces in the marine environment,” said a spokeswoman.
Ship noise could drown the love song of toadfish
“The males will actually court females by singing to them, and their song is so loud you can hear it just standing next to the water's edge at night. It's spectacular.”
But she is worried that this timeless ritual, and the procreation which depends on it, may be at risk. The increasing noise made by ships could mask the toadfish’s mating call - and threaten its survival.
Cullis-Suzuki is a marine biologist from British Columbia in Canada. She has been researching the impact of ship noise on a species of toadfish called the plainfin midshipman in the northwest Pacific for the University of York in England.
“These highly vocal fish communicate by humming, grunting and growling, and their low frequency calls overlap with boat noise, showing the potential for boats to mask fish communication,” she says.
“Boat noise also appears to cause increased movement in these fish, which likely corresponds with increased stress levels, energetic costs, and ultimately, could impact on reproductive success.”
She stresses that noise does not impact all species in the same way, and that there are complex interactions that must be taken into account, like the relationships between predators and prey. “Our studies are showing just how complex and unpredictable responses can be in the marine environment,” she says.
LIsten to short recordings of the plainfin midshipman (thanks to Sarika Cullis-Suzuki):
The damage being done by noise pollution at sea
researchers / finding
Technical University of Catalonia, Spain / squid, octopus and cuttlefish suffer “massive acoustic trauma” destroying hair cells vital for balance and position
University of La Laguna, Spain / noise causes deformities and developmental delays in scallop larvae
Fisheries and Oceans Canada / snow crabs exposed to noise suffer bruising to internal organs and ovaries
Curtin University, Australia / underwater air guns cause severe and extensive damage to the ears of pink snapper fish
University of York, England / ship noise could mask the mating calls of toadfish
University of Bristol, England / noise kills the eggs and larvae of sea hares
University of Bristol, England / noise can slow the reactions, disrupt the feeding and increase stress in shore crabs
St Andrews University, Scotland / whales lose up to 90% of their opportunity to communicate with family members in busy shipping lanes
The Pennsylvania State University, US / North Atlantic right whales call louder when ocean noise levels rise
New England Aquarium, US / evidence that ship noise causes “chronic stress” in North Atlantic right whales
University of Bristol, England / eels exposed to noise breath faster and respond slower to predator attacks