A new study suggests that noise pollution from motorboats poses threats to small fishes. Underwater noise subjects these marine animals to great amounts of stress that give predators the advantage.
Noise pollution has been found to affect the ability of larger sea animals such as whales and dolphins to communicate but this new study suggests that underwater noise may also negatively impact small fishes.
In the study published in the journal Nature Communications, a team of international marine biologists found that the rate at which the fishes are seized by predators can increase two-fold when motorboats are nearby.
The noise emitted by passing motorboats surges stress levels among young coral fish and decreases their ability to escape from an impending predator attack. As a result, they are seized more easily.
"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," Dr. Stephen Simpson, from the University of Exeter, said.
The Natural Environment Research Council (NERC) and the ARC Centre of Excellence for Coral Reef Studies funded the study titled, "Anthropogenic noise increases fish mortality by predation".
The team of British, Australian and Canadian scientists conducted both field and laboratory experiments to study predator-prey interactions and bioacoustics to land to their findings. They used real boat noise to test its effects on the survival rates of young Ambon damselfish (Pomacentrus amboinensis) when they are faced with their natural predator, dusky dottyback (Pseudochromis fuscus).
The study shows that if stress and poor responses are combined, predators get the advantage of capturing small fishes, thus reducing the latter's chance of survival.
"Our study suggests that a common source of noise in the marine environment has the potential to impact fish demography, highlighting the need to include anthropogenic noise in management plans," the researchers concluded.
The researchers hope that adequate measures should be undertaken in managing local environmental stressors like noise to avert its negative effects on marine life. This study aims to inform authorities on the effects of noise pollution on smaller fishes, which can be fatal if left uncontrolled.
