Noise pollution makes fish vulnerable to predators: study

Noise from human construction projects such as windfarms and spreading cities can disrupt schools of fish, making certain marine species vulnerable to predators.

Human activities, like transport and construction, generate a lot of noise that travels faster in water than in air.

Cohesion and coordination in fish schools are essential in helping some animals avoid predators and exchange information socially.

For the study, researchers from University of Bristol in the UK played back recordings of pile-driving, used in the construction of marine infrastructure like windfarms and piers, to small schools of seabass.

As many as 450 fish were tested in shoals of four individuals each in an aquarium.

The fish became less cohesive and coordinated during the playbacks, compared to when only normal ambient sea sounds were played to them.

"By using state-of-the-art computer tracking software, we were able to measure and analyse the movement of individual fish and the shoal as a whole in great detail," said Christos Ioannou from the University of Bristol.

"This is one of the few studies to explore how pollution from human activity impacts schooling behaviour in fish," said Ioannou.

The changes in the fish's behaviour when exposed to noise suggests they may be more susceptible to predators, as schooling behaviour is so useful in avoiding being eaten, researchers said.