Porpoises Avoid Offshore Pile Driving Up to 9 Miles
A study at the Dogger Bank C wind farm in the North Sea measured how far harbor porpoises stay away from construction noise.
Updated on Nov. 5, 2026 in Environmental
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Researchers used 27 passive acoustic monitoring moorings over 5.5 months at the Dogger Bank C offshore wind farm in the North Sea. The average effective deterrence range during unmitigated piling was 14.4 km, or roughly nine miles.
Why it matters
Conservation planning for offshore wind depends on knowing how far from a construction site harbor porpoises will stay away. As offshore wind development expands, accurate disturbance estimates for marine mammals become more important.
The study used 27 passive acoustic moorings over 5.5 months and estimated an average effective deterrence range of 14.4 km for unmitigated piling. Bubble curtains can greatly reduce that zone, but the extraction does not quantify the reduction.
The players
Dogger Bank C offshore wind farm
An offshore wind installation in the North Sea that served as the site of the monitoring study.
The details
Porpoise activity was strongest nearest to construction and declined sharply within about the first 10 km. Piling longer than one hour was generally associated with a higher probability of response than shorter piling, and detections were lowest near active hammers.
Timeline
Monitoring ran for 5.5 months at Dogger Bank C.
Porpoise avoidance effects typically dissolved within 24 hours following hammer strikes.
Roadmap
Empirical data from Scottish offshore wind sites already show similar avoidance thresholds for unmitigated monopiles, and this Dogger Bank C study extends that pattern to the North Sea. As offshore wind expands, these deterrence distances will shape how developers plan construction and mitigation.
Findings like these help determine how far construction zones must extend to protect marine mammals from noise. Developers may need mitigation such as bubble curtains to shrink the area where porpoises avoid active sites.
The takeaway
Mitigation measures such as bubble curtains can substantially reduce the distance over which porpoises avoid offshore piling. Planners should weigh these options when scheduling long piling operations near sensitive habitat.
Further reading
Explore more on Environmental research into how construction noise affects marine life.
Source note: This article includes information reported by Ecoportal.
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