Balancing risks of injury and disturbance to marine mammals when pile driving at offshore windfarms ...

• Main Authors: Thompson, Paul, Graham, Isla, Cheney, Barbara, Barton, Tim, Farcas, Adrian, Merchant, Nathan
• Format: Dataset
• Language: English
• Published: Dryad 2020
• Subjects: acoustic disturbance; behavioural response; environmental risk assessment; Renewable energy; Underwater noise; cetaceans; FOS Earth and related environmental sciences; Harbour Porpoises; Harbour porpoise
• Online Access: https://dx.doi.org/10.5061/dryad.34tmpg4hs; https://datadryad.org/stash/dataset/doi:10.5061/dryad.34tmpg4hs

1. Offshore windfarms require construction procedures that minimise impacts on protected marine mammals. Uncertainty over the efficacy of existing guidelines for mitigating near-field injury when pile-driving recently resulted in the development of alternative measures, which integrated the routine deployment of acoustic deterrent devices (ADD) into engineering installation procedures without prior monitoring by Marine Mammal Observers. 2. We conducted research around the installation of jacket foundations at the UK’s first deep-water offshore windfarm to address data gaps identified by regulators when consenting this new approach. Specifically, we aimed to a) measure the relationship between noise levels and hammer energy to inform assessments of near-field injury zones, b) assess the efficacy of ADDs to disperse harbour porpoises from these zones. 3. Distance from source had the biggest influence on received noise levels but, unexpectedly, received levels at any given distance were highest at low hammer ... : Piling noise and Acoustic Deterrent device signals were measured using calibrated broadband noise recorders (Soundtrap ST300HF, Ocean Instruments) moored 2 m above the seabed. An array of moored echolocation detectors (V.0 and V.1 CPODs (www.chelonia.co.uk)) was used to assess variation in harbour porpoise detections in relation to experimental ADD exposure. Data on the timing of piling operations, pile-hammer energies used, and pile penetration depths were provided by the wind farm developer (Beatrice Offshore Wind Ltd). ...