Offshore construction using gravity-base foundations indicates no long-term impacts on dolphins and harbour porpoise

• Published in: Marine Biology
• Main Authors: Potlock, Kelsey M., Temple, Andrew, Berggren, Per
• Other Authors: Biological and Environmental Science and Engineering (BESE) Division, Red Sea Research Center (RSRC), School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK, Office of Protected Resources, NOAA Fisheries, 1315 East West Highway, Silver Spring, MD, 20910, USA
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer Science and Business Media LLC 2023
• Subjects: Harbour porpoise; Lagenorhynchus albirostris; Phocoena phocoena
• Online Access: http://hdl.handle.net/10754/692886; https://doi.org/10.1007/s00227-023-04240-1

There are concerns about the short- and long-term effects on cetaceans from offshore construction using pile-driving. Gravity-base foundations and anchored floating turbines are alternative installation methods that may have less impact on cetaceans. In this study, we investigated the response of dolphins (Tursiops truncatus and Lagenorhynchus albirostris) and harbour porpoise (Phocoena phocoena) to the construction of wind turbines using gravity-base foundations off Blyth, Northumberland, United Kingdom using cetacean echolocation recorders (C-PODs). Data were collected at nine sites across 3 years (2016–2018) before, during and after construction. Generalised additive mixed models were used to investigate temporal, environmental, and anthropogenic drivers of dolphin and porpoise occurrence from 143,215 h (5967 days) of C-POD data. The models explained 27% and 30% of the deviance in dolphin and porpoise occurrence, respectively. Overall, the results showed no long-term effect on the dolphin occurrence from the construction of the gravity-base wind turbine array. In contrast, porpoise occurrence increased by 32% and 75%, respectively, in the years during and after construction, compared to the before-construction year. Other predictors of dolphin and porpoise occurrence included month, hour of day, tidal currents and vessel sonar activity. Our findings indicate that wind turbine installation using gravity-base foundations had no long-term effects on the occurrence of dolphins or porpoise and may represent an offshore construction methodology that is less impactful to dolphins and harbour porpoise than impact pile-driven turbine installation methods. These results are important for future offshore energy developments; however, further studies are recommended to investigate potential species and location variations. Funding for this study was provided by EDF Renewables (BOD/PR/0081). We would like to thank EDF Renewables for both facilitating and funding this project. We thank the crew of the RV Princess Royal , ...