Monitoring Noise Levels in the Marine Environment

The European Marine Energy Centre (EMEC) has designed a programme of acoustic surveys to determine the potential impact that marine renewable developments may have on local species and habitats.

This summer, EMEC will deploy a series of acoustic surveys designed to monitor noise levels of marine energy technologies at its ocean energy test sites in Orkney.

The acoustic survey programme will attempt to monitor:

•wave energy converters demonstrated by Mocean Energy and AWS Ocean Energy at EMEC’s Scapa Flow scale wave energy test site, via the European Maritime and Fisheries Fund (EMFF) SEA Wave project; and
•tidal energy technologies demonstrated by Orbital Marine Power and Magallanes Renovables at EMEC’s Fall of Warness tidal energy site, funded by Horizon 2020 projects, FloTEC and MaRINET2.

EMEC will deploy static and drifting hydrophones (underwater microphones) to characterise the acoustic signature of devices during operation. The data will be compared to baseline data collected prior to technologies being present on site, allowing developers to build an acoustic characterisation of their technology.

Marine mammals use a wide band of acoustic frequencies to navigate and communicate. As the ocean energy sector is still in development, it is necessary to establish whether exposure to noise from technologies could result in behavioural changes such as displacement from key habitats, or disturbance at breeding, foraging or social sites.

This is particularly important in Orkney where the local council has signed a Memorandum of Understanding with Crown Estate Scotland which will take forward plans to establish a massive wind renewables facility in Scapa Flow.

You can read about that here: Developing a Deep Water Facility in Scapa Flow “a once in a generation opportunity”

In March 2021 a report was published by the Scottish Government on the use of Acoustic Deterrent Devices (ADDs) by the aquaculture sector. ADDs work by emitting a loud low frequency sound and affect not just seals but other marine life.

the aquaculture sector can no longer obtain a licence to kill seals for the purpose of preventing serious damage to finfish farms or to protect the health and welfare of farmed fish. Alternative and more effective non-lethal measures will therefore be required to address seal interactions with farmed fish in the future.

Aquaculture – ADDs Report
Image credit Noel Donaldson

There is increasing concern that the use of ADDS is not only disturbing to marine mammals but that it damages their hearing. This can affect their: breathing, breeding, nursing young and their means of communication.

The report concludes that there is a need for much more research on the use of ADDs and other devices in the marine environment which emit sound. Given the future plans being proposed for the unique marine environment of Scapa Flow which would become much busier than it even is today, this research by EMEC is crucial to add to the body of data being collected on sound in the marine environment.

EMECs work will measure the acoustic noise of renewable devices. The collection of this data will lead to a better understanding of what noise is emitted, any potential impacts on marine life, and what mitigations could be put in place to protect marine life.

Donald Leaver, Environment & Consents Officer at EMEC said:

“EMEC is at the forefront of monitoring and collecting data for environmental assessments for wave and tidal energy.

“The sector is determined to find new renewable energy solutions to help combat climate change so it’s vital that we understand how new technologies may impact marine life to mitigate any potential impacts.

“Acoustic monitoring will also give confidence to regulators when consenting technologies supporting the continued development of the sector.”

Mocean Energy deploy Blue X at EMEC Scapa Flow wave energy test site (Credit Colin Keldie)

Reporter: Fiona Grahame

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