“In this case, we think the prey fish are more susceptible to noise than the predator fish, but that might be the other way around in other cases,” he said.
Two-stroke outboard motors are extremely common on most coasts with, for example, 12m registered motor boats in the US alone. But, compared to climate change, ocean acidification, pollution and overfishing, cutting noise pollution is easier to deal with in principle.
Simpson said there could be marine quiet zones, where motor boats are excluded or have to use quieter motors. Four-stroke motors are quieter and electric motors are getting more powerful and are much quieter, he said.
Mark Meekan, at the Australian Institute of Marine Science and part of the research team, said: “If we can reduce the effect of local noise pollution, we can build greater resilience in reef communities to looming threats such as global warming.”