The objective of this project was to perform experimental research on effects of pile-driving noise on cod and sole. The study was intended to improve the understanding of the threshold of exposure that lead to behavioural responses in commercially important fish. A further objective was to define the characteristics, the scale and the duration of responses as a function of sound exposure. Finally, the study aimed to interpret the results in light of pile-driving operations in the marine environment. The results of the study shall guide regulatory advice and the implementation of mitigation measures in the construction of offshore wind farms in UK waters.