Assessing impacts to marine mammals
A variety of human pressures affect marine mammals in UK waters, many of which resulting from offshore industries. JNCC's Marine Management Team (MMT) provide high quality marine mammal conservation advice to governments and industry in relation to offshore developments and operations.
JNCC's role
The MMT fulfil part of JNCCs statutory role by providing UK regulators with nature conservation advice during the offshore consenting process. This includes reviewing applications with the potential to introduce noise into the marine environment or damage habitats or processes important to marine mammals or their prey. We provide marine mammal advice to regulators and industry during all stages of a development’s life cycle including screening, scoping, environmental survey design, impact assessments and decommissioning. The team also work to identify areas where guidance would be beneficial, and work with regulators and industry to develop them.
Should you have any queries or require advice, you can contact JNCC at OIA@JNCC.gov.uk
Environmental impact assessments
When submitting applications to undertake operations at sea, it is a requirement to consider the potential impacts from the proposal, including to the environment.
This is usually in the form of an environmental impact assessment (EIA). This process assesses the environmental consequences (positive and negative) of a plan or project. An Environmental Statement (ES) is the written material submitted to a regulator or planning authority to fulfil legal requirements such as the EIA Regulations[1], and will contain the results of the EIA. The size of the assessment and level of detail required will depend on the scale of the project, what and where it is and environmental sensitivities.
[1] For example, the Marine Works (Environmental Impact Assessment) (Amendment) Regulations 2017
What to assess
When considering potential impacts to marine mammals, a key consideration is whether there might be any impacts from noisy activities, for example piling, explosive use or geophysical surveys. A noise risk assessment is undertaken, which considers how loud the noise will be, at what distance from the activity could marine mammals be injured or disturbed, what can be done to reduce the level of noise and animal exposure and what impacts could it have at the population level.
Typically, noise modelling is undertaken to estimate distances at which hearing damage may occur. Depending on the results, mitigation may be required to ensure no marine mammals are in the vicinity before the activity begins. Regulators review these assessments and consult with statutory nature conservation bodies (SNCBs) including JNCC before deciding whether to consent the project.
Consideration should also be given to supporting habitats and processes important to marine mammals including those that relate to the seabed, water column and prey, particularly in protected areas. For example, activities that directly impact the seabed, such as dredging/burial, sweeping and deposits, could potentially affect a preferred prey species such as sandeel, making them unavailable to marine mammals as a food source. The links between habitat-prey-predator are poorly understood however and more research is needed to provide the evidence needed to properly assess the risk of certain activities. The seabed is not considered sensitive to noise disturbance however underwater sound has the potential to affect prey fish species, for example noise could disturb fish away from a specific area where marine mammals forage. Noise also has the potential to cause hearing damage to some fish species.
Auditory injury thresholds
Criteria to help predict potential auditory injury to marine mammals were first considered in 2002 when the US National Marine Fisheries Services (NMFS) brought together a panel of scientists to consider the problem of how to assess impacts from noise on marine mammals. This resulted in the publication of auditory exposure criteria in 2007 (Southall et al., 2007). These criteria were updated in 2016 (NMSF, 2018) and most recently in 2019 (Southall et al., 2019).
The criteria introduced the concept of marine mammal hearing groups or frequency weighted hearing groups. This involved categorising marine mammals into groups based on what was known about their hearing. The criteria also presented auditory injury thresholds, representing levels of noise above which it is thought auditory injury may begin to occur.
In 2010, guidance produced by JNCC, Natural England and Natural Resources Wales (formally Countryside Council for Wales) advocated the use of injury thresholds proposed in Southall et al. 2007 when assessing impacts from noise to marine mammals in UK waters (JNCC, 2010). Given the more recent publications updating the criteria, they now consider NMSF 2018 (sometimes referred to as NOAA 2018) and Southall et al. 2019 to represent the most comprehensive and up to date scientific knowledge available to use in assessments of the risk of auditory injury to marine mammals and advise their use in noise assessments.
European protected species
Marine European Protected Species (EPS) are those listed on Annex IV of the Habitats Directive and whose natural range includes any area in Great Britain. In UK waters, these consist of cetaceans (whales, dolphins and porpoises), turtles and the Atlantic Sturgeon.
The Habitats Directive is transposed into UK law under the Habitat Regulations (HR) for England and Wales (as amended) and The Conservation of Offshore Marine Habitats and Species Regulations 2017, which make it an offence to kill, injure, capture or disturb European marine protected species. Similar legislation exists for Scottish and Northern Ireland inshore waters.
JNCC, Natural England and Natural Resources Wales (previously the Countryside Council for Wales) provided draft guidance regarding the protection of cetacean EPS from injury and disturbance. This guidance provides a resource for marine users, regulators, advisers and the enforcement authorities when considering whether an offence of deliberately disturbing or injuring/killing a cetacean EPS is likely to occur or has occurred as a result of an activity.
In addition, JNCC have developed mitigation guidelines covering key activities, adherence to which is considered to minimise the risk of committing an injury offence.
Related publications and data sources
JNCC have helped develop a number of tools to assist in assessing potential impacts to marine mammals in UK waters and developing mitigation protocols:
- Guide to population models used in marine mammal impact assessment (August 2017). Provides an overview of the main types of approaches used in the assessment of population level consequences of impacts to marine mammals before exploring specific examples in more detail.
- Management units for cetaceans in UK waters (January 2015). Agreed management units for the seven most common cetacean species in UK waters, providing an indication of spatial scales at which impacts of plans and projects alone, cumulatively and in-combination, need to be assessed.
- Using the Interim PCoD framework to assess the potential impacts of offshore wind developments in eastern English waters on harbour porpoise in the North Sea (June 2017). A population assessment model is used to investigate potential cumulative effects that could arise from the currently planned 12 years of English wind farm construction.
- Evidence base for application of acoustic deterrent devices (ADDs) for marine mammal mitigation in coastal and offshore waters (March 2019). Provides a summary of available evidence regarding the effects of acoustic deterrent devices.
- Joint Cetacean Protocol. Project built on datasets utilised in Reid et al 2003 to produce robust estimates of cetacean density, distribution and population trends in UK waters.
- Site Information Centres provide background information and conservation advice including guidance regarding management of activities within offshore protected sites, including those designated for marine mammals.
Other useful links
Atlas of cetacean distribution in north-west European waters. Reid et al 2003.
SCANS lll: https://scans3.wp.st-andrews.ac.uk/
Special Committee on Seals (SCOS): Special Committee on Seals – SCOS | SMRU
UK Cetacean Stranding Investigation Programme: http://ukstrandings.org/
Offshore Renewables Joint Industry Programme (ORJIP): http://www.orjip.org.uk/
The E&P Sound and Marine Life Joint Industry Programme: http://www.soundandmarinelife.org/
References
Southall, B. L., Bowles, A. E., Ellison, W. T., Finneran, J. J., Gentry, R. L., Greene, C. R., Kastak, D., Ketten, D., Miller, J. H., Nachtigal, P. E., Richardson, W. J., Thomas, J. A. and Tyack, P. 2007. Marine mammal noise exposure criteria: initial scientific recommendations. Aquatic Mammals, 33, pp. 411-521.
JNCC 2010. Joint nature Conservation Committee, Natural England and Countryside Council for Wales. October 2010. The protection of marine European Protected Species from injury and disturbance: guidance for the marine area in England and Wales, and the UK offshore marine area.
NMFS 2018. 2018 Revision to Technical guidance for assessing the effects of anthropogenic sound on marine mammal hearing. National Marine Fisheries Service, U.S. Dept. of Commerce, NOAA Technical Memorandum NMFS-OPR-59, 167 p.
Southall, B.L., Finneran, J.J., Reichmuth, C., Nachtigall, P.E., Ketten, D.R., Bowles, A.E., Ellison, W.T., Nowacek, D.P., and Tyack, P.L. 2019. Marine mammal noise exposure criteria: updated scientific recommendations for residual hearing effects. Aquatic Mammals, 45, 125-232.
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