Construction noise harmful to fish

 

Types of piling and drilling sounds emitted during the building of offshore structures are harmful to the health of European sea bass, researchers at Newcastle University have discovered.

As well as experiencing increased stress levels when exposed to this type of construction noise, researchers also found that when recordings of piling sounds were played and an approaching predator was mimicked, the fish showed signs of being confused when encountered by the potential predator - making more turns than usual and failing to escape from the predator.

In addition, exposure to sounds produced by drilling caused the sea bass to actively stay away from these areas; instead choosing to spend more time in what the research team referred to as the ‘safe zone’.

Researchers added that the fish also took more time to recover from exposure to the underwater sounds.

“The sea has turned into a much noisier environment than it once was. The effects we witnessed were only minor, but could possibly disrupt the ability of the seabass to keep ‘in tune’ with its environment,” Llaria Spiga, lead researcher, explained.

“Like many other species of bony fish, a characteristic known as ‘startle and response’ is relied upon heavily by sea bass to allow them to escape from any potential predators.

“Our research has shown that it can be harder for fishes to recognise and react appropriately to predators when exposed to underwater noises, as well as interfering with their innate ability to detect food,” she added.

“Furthermore, if fishes actively avoid areas where man-made marine noises are present, it could cause them to not enter their usual spawning grounds, or at least affect the ability for them to communicate.”

The drilling sound played to the seabass was a recording from the installation of a new tidal barrage on the English Channel, while the piling sound was from a new lifeboat station construction at Swansea Bay.

Sea bass and many other species of fish have a hearing range of 100 -- 1000 Hz, which both piling and drilling sounds overlap with.