Evidence base for application of Acoustic Deterrent Devices (ADDs) as marine mammal mitigation (Version 2: February 2020) 2020

Abstract

Subsea noise produced by anthropogenic activities in coastal and offshore waters has the potential to cause injury or death to marine mammals. To reduce this risk, mitigation solutions have included the deployment of acoustic devices in proximity to the noise-producing activity, to deter animals from potential injury zones. There is also the potential to use acoustic devices for collision risk mitigation.

Acoustic devices have been applied across various marine industries. The range of applications for these devices (i.e. different industries, intended purpose, or different target species), has led to a wide variety of available technologies on the market. Whilst most emit medium to high frequency sounds, the acoustic characteristics of each device differ in terms of the sound levels produced, frequency range, temporal pattern/duty cycle and harmonics. In addition, there are also differences in the method of deployment and operating functions.

Extensive reviews of devices are available, however, a single report, collating and summarising the evidence around their effectiveness was considered useful and enables the information to be processed readily by Statutory Nature Conservation Bodies (SNCBs) when advising regulators on the use of acoustic devices to deter marine mammals from areas where there is a risk of injury or death. The report reviews evidence on the effectiveness of acoustic devices at deterring a range of marine mammal species. This includes a coarse assessment of the risk of injury from ADDs themselves, with a general conclusion that the risk of injury is likely to be low for all devices, although this is context dependent. The report also provides a summary of the key relevant legislation and regulations pertaining to the protection of marine mammals in the UK.

Note: Version 1 of this report was published in 2018 and was entitled 'Guide for the Selection and Deployment of Acoustic Deterrent Devices'. Following from feedback from manufacturers, Version 2 contains the following changes:

• Title was changed to better reflect the content, i.e. specification and evidence review rather than a guide on how to choose and deploy ADDs.
• The specifications of some ADDs were corrected or completed as well as some of the names. In some instances, ADDs have had name changes whilst keeping the same specifications. This had led to some mistakes which have been amended in the new report.
• A series of references that had not previously been considered were added.
• The evidence scoring was clarified and the evidence associated with each ADD was reviewed which led to a couple of scoring changes.
• Section 4 on legislation and regulations was updated.
• Changed ADD numbering in report tables and database to match the appendices to make it easier to refer to the specifications in the appendices.

Note: This report is a ‘live’ document and the intent is for it to be updated periodically in line with additional information on the acoustic deterrents described herein, and on the basis of new technologies that become available.

Whilst every effort was made to ensure that the information in it is complete, accurate and up-to-date, no guarantee is provided and JNCC shall have neither liability nor responsibility to any person or entity with respect to any loss or damage arising from the use of this report. We will act on any inaccuracies that are brought to our attention and will do our best to correct them in subsequent versions.