When European sea bass are exposed to sounds of the construction of offshore structures, they exhibited signs of confusion and stress, according to a study published in Marine Pollution Bulletin.
When researchers from Newcastle University (UK) played recordings of piling sounds and mimicked an approaching predator, the European sea bass they were observing appeared confused, making more turns and did not swim away from the "predator". They also needed more time to recover after being exposed to such sounds.
Lead researcher Ilaria Spiga explained, “Sea bass, along with other bony fishes, rely on a characteristic 'startle and response' mechanism to get away from predators. Exposure to underwater noises can make it harder for fishes to detect and react to predators. It could also impair their own ability to detect food.
Spiga added that man-made marine noise may have an adverse effect on the fish’s reproduction as well. This was because the fish may deliberately avoid such areas due to the noise, which may prevent them from entering spawning grounds or affect communication amongst the community.
Besides construction noises, other elements like offshore construction, shipping and certain onshore activities can also contribute to underwater noise.
The research team are proposing that the duration of underwater drilling and piling be limited, or that drilling be replaced by piling, so that fish can have time to recover from the physiological impact caused by underwater noise.