New research has shown that acoustic deterrent devices (ADDs) can be effective at protecting marine mammals from offshore wind construction.
An MCR researcher deploys a microphone (Credit: MCR)
Led by the Carbon Trust and the Offshore Renewables Joint Industry Programme (ORJIP), the project demonstrated that minke whales showed a clear response to ADDs. The devices, which emit a high-frequency noise at the upper limit of human perception, are more commonly used to deter seals and porpoises from commercial fishing grounds. Researchers are now exploring their effectiveness around wind farm construction, where the percussive pile-driving required for foundations can be damaging to marine mammals.
The study, carried out by Marine Conservation Research (MCR) in Faxaflói Bay in southwest Iceland, gauged the response of numerous minke whales to ADDs using video range tracking (VRT). The researchers employed a Lofitech Seal Scarer which, according to the manufacturer’s website, uses a pulse generator and an amplifier that transmits random bursts of audio frequency signals to the transducer, where they are converted into intense sound. On all 15 occasions of ADD deployment, the whales were observed to move away from the device once it was activated, and also exhibited faster swimming speeds.
A Seal Scarer acoustic deterrent device used in the project (Credit: MCR)
“The results from this research are really exciting and are a result of many organisations working together to help shed light on this important area,” said Olivia Burke, manager of the ORJIP ADD project at the Carbon Trust.
“The findings will help increase industry and regulator confidence in the use of ADDs to actively manage the protection of marine mammals during the piling phase of construction.”
Funding for the project came from a trio of northern European energy companies in the shape of Innogy (Germany), Ørsted (formerly Dong, Denmark) and Statoil (Norway). According to them, successfully deterring marine mammals from offshore wind construction sites not only protects the animals, it also prevents delays to the builds.
“This is an important project and we have proactively engaged and supported the ORJIP ADD programme in order to ensure our projects look after the safety of these important species,” the three energy companies said in a joint statement. “We are pleased to see that these trials have increased the evidence base proving the efficacy of ADDs in deterring marine mammals.”