Where the action is: underwater noise and its effects on sea bass larvae (Dicentrarchus labrax) at a piling platform

The pile-driving of monopiles has triggered a range of ecological questions regarding the impact of anthropogenically generated low frequency impulsive underwater noise on marine wildlife. This study tackles the impact of pile-driving on fish eggs and larvae which form the basis of fish populations and are an important prey for pelagic predators. Given that their transport is primarily current based; they are exposed to underwater noise present in the water column
One of the aims of the OffNoise project is to determine if pile-driving causes 100 % mortality at the piling source itself. The first opportunity to conduct an experiment was the piling activity during the construction of the Northwind NV offshore wind farm in June 2013. From the piling platform, sea bass (Dicentrarchus labrax) larvae were lowered into the sea and exposed to a complete piling event, at a distance of 40m from the pile-driving source. Simultaneously to each repeat, the underwater sound pressure and particle motion were recorded. Mortality and respiration rates were monitored, cortisol samples taken and surviving larvae were reared in the lab to examine effects on development and growth. As a control, the same procedures and measurements were done during a piling pause.