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WCVM researcher Maud Ferrari was part of a study recently published by Nature Communications. Submitted photo.

Motorboat noise increases risk for fish

Noise from motorboat traffic makes some fish more than two and a half times more likely to be eaten by predators, according to an international team of researchers including biologists from the University of Saskatchewan (U of S).

"Previous laboratory work has shown that noise can reduce foraging success with fish and crabs," said Doug Chivers, U of S professor of biology. "This is the first study to show that real-world noise such as that from motorboats can have a direct consequence on fish survival."

Chivers, along with Maud Ferrari with the Western College of Veterinary Medicine and colleagues from the United Kingdom and Australia, looked at the behavior of the ambon damselfish, a 10-centimetre, bright yellow denizen of Australia's Great Barrier Reef, and its natural predator, the dusky dottyback.

The researchers simulated predator attacks both with tanked fish and at field sites on the reef. They found that when the sound of motorboats was around, the damselfish were six times less likely to startle from a simulated predator attack. They were also about 20 per cent slower in getting out of the way, allowing the simulated predator to get 30 per cent closer before they fled.

What this means for different species of fish and other aquatic wildlife will depend on the animals in question.

"The winners and losers in other predator-prey interactions will depend on various factors," Ferrari said. "Also, different species may be more or less sensitive and tolerant to noise, and of course different sorts of water craft produce different noise levels."

University of Exeter marine biologist Stephen Simpson led the work which is published in Nature Communications. He explained that unlike looming challenges of ocean acidification and climate change, noise is a problem well within the reach of humans to remedy. Marine quiet zones or buffer zones and steering activity away from known spawning sites, are just a couple of options.

"If you go to the Great Barrier Reef, there is a lot of noise from motorboats and diving equipment in some places," Simpson said. "But unlike many pollutants, we have control over noise. We can choose when and where we make it, and with new technologies, we can make less noise."
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