Motorboat noise doubles predators' chances of capturing fish

Noise from passing motorboats increases stress levels in young coral reef fish and reduces their ability to flee, doubling the rate at which they are captured by predators, a new study has found.
The study is the first to show that real-world noise, in this case the common noise of motorboats, can have a direct consequence on fish survival.
"We found that when real boats were motoring near to young damselfish in open water, they became stressed and were six times less likely to startle to simulated predator attacks compared to fish tested without boats nearby," said Stephen Simpson, from the University of Exeter in UK.

"The combination of stress and poor responses to strikes by predators is why these fish became such easy prey," said Andy Radford, from University of Bristol in UK.
Researchers combined laboratory and field experiments, using playbacks and real boat noise, to test the impact of motorboat noise on survival of young Ambon damselfish during encounters with their natural predator the dusky dottyback.
Rather than being despondent, the team is optimistic about the possibilities for management of noise and its potential impact.

"Unlike many pollutants we can more easily control noise. We can choose when and where we make it, and with new technologies, we can make less noise," said Simpson.

"For example, we could create marine quiet zones or buffer zones, and avoid known sensitive areas or times of year when juveniles are abundant," said Simpson.
Managing local environmental stressors such as noise is an essential first step in protecting the marine environment.
"If we can reduce the effect of local noise pollution we build greater resilience in reef communities to looming threats such as global warming and ocean acidification," said Mark Meekan, from the Australian Institute of Marine Science.
The study was published in the journal Nature Communications.