The global extent of marine renewable energy developments (MREDs) has been researched and considered in relation to their potential impacts on cetaceans. There is currently an unprecedented expansion of MREDs, focused on European waters, with large-scale developments covering thousands of square kilometres being planned. However, data on the likely impacts of these developments on cetaceans is lacking or, at best, significantly limited.
This research highlights the rapid expansion of MREDs, particularly in Europe, and more recently in China and off the east coast of the USA. Offshore wind farms continue to be the technology developing most swiftly; wave and tidal energy devices are mostly still in the testing phases, with the majority of operational sites being used to test the technology.
Information about the location of offshore wind farms is readily available; however information on wave and tidal sites is much more difficult to obtain, probably due to the fact that these are relatively new technologies and still being developed. It is likely that this report under-represents the actual extent of wave and tidal energy sites globally.
Around the UK many of the sites where MREDs are being built are within or adjacent to areas that are critical habitats for cetaceans; the impacts of these developments on cetaceans are not fully understood. The limited research conducted so far has shown the potential for MREDs to cause behavioural changes in harbour porpoises (Phocoena phocoena), which leave the area during construction and in some instances did not later return to their usual numbers. Even where areas have been recolonised, it is not clear if these are the same animals returning or new animals moving into the area. The significance of such disturbance is not understood.
Data on protected and critical areas for cetaceans outside the UK have been difficult to obtain, however, there will be other important areas for cetaceans that overlap, or are adjacent to, MREDs.
The limited available information on the impacts of MREDs on cetaceans indicates a significant risk of negative consequences, with the noise from pile driving highlighted as a major concern with the potential to cause physical harm. Marine renewables devices may impact on cetaceans in ways ranging from collisions to habitat displacement due to the effects of noise and disturbance.
Some have suggested that MREDs may have ecological benefits but these have yet to be fully assessed.
More strategically, and as an essential first step, research is required on a wider scale to identify critical habitats for cetaceans. This would enable governments and developers to avoid such areas or apply stricter protection and help ensure that the deployment of marine renewables will not threaten cetaceans.
The need for urgent and joined-up research into the impacts of MREDs on cetaceans, and the wider marine environment, is clear. Research is required to understand the short and long term impacts and should be conducted well ahead of developments to establish baselines as well as during construction, operation and decommissioning as well as years after decommissioning. To enable the impacts to be fully understood, adequate baseline data of cetacean populations is required, against which any changes can be measured. This will enable the impacts to be fully assessed, managed and mitigated.
This report highlights the fact that the impact assessment process is currently based on only very limited knowledge on both cetacean populations and the impacts of MREDS on the marine environment.
As the data are limited it is highly unlikely that conclusions on the impacts of a particular development on cetaceans, and the wider marine environment, are reliably based. As a result, developments are being consented in areas that are critical for cetaceans without giving adequate consideration to the potential wider and longer term consequences, and without appropriately focused research. With appropriate research on critical habitats for cetaceans, and the impacts of MREDs on cetaceans, these decisions will be more reliably based and allow relevant mitigation measures to be identified.
There is an urgent need for governments, developers and other stakeholders to engage in wide-ranging ecological research to help fully understand, and mitigate, the impacts of MREDs and aid good decision making. The expansion of the industry must be in step with understanding of the known and potential impacts on the marine environment.
WDC makes the following critical recommendations in order to ensure the development of this new industry, which assists with climate targets, is undertaken without impacting cetaceans and other mobile species:
- Until the impacts of MREDs can be fully assessed and mitigated, further developments within, or that may affect, areas that have already been identified as important for cetaceans must be avoided.
- Areas of critical habitat for cetaceans need to be identified in advance of leasing rounds to avoid developing potentially sensitive areas. For example, many shallow waters in northern Europe are important calving and nursing areas for harbour porpoises, which are also favourable sites for wave and tidal developments. This will also avoid costly changes in plans, unwieldy environmental constraints or delays.
- To enable any impacts of MREDs on cetaceans to be fully understood, adequate baseline data of cetacean populations, over a minimum of 2 years, and preferably more, ahead of development is required, against which any changes can be measured.
- There is clearly a requirement for further research on the impacts of MREDs on harbour porpoises and also on other cetacean species, their prey and their habitats in order to help understand and mitigate the impacts of MREDS on cetaceans. The research needs to be sufficient to detect impacts and cover all stages of the lifetime of the MREDs, pre-construction, during construction, operation and decommissioning as well as several years after to be able to evaluate their impacts on cetaceans and also consider the cumulative effects. For new devices, this needs to be conducted at the testing phase before wide scale deployment. For devices that are already operational, or have been approved for use, the impacts on cetaceans and other marine wildlife need to be studied at various sites to fully assess any impacts.
- Baseline data is also required on strandings to develop a reference point from which any increases in strandings rates due to MREDs can be understood.
- Sharing of the results of the research into both critical habitat areas for, and the impacts of MREDs on cetaceans is essential. Data needs to be made available to developers and governments to enable mitigation measures to be identified. To enable this there needs to be improved information and datasharing facilities.
- Until mitigation measures to reduce the noise of pile driving are tested for effectiveness, the best method is to avoid pile driving altogether and use alternative foundations. Strategic investment in alternative techniques is urgently required.
- International standards for and auditing of impact assessments need to be developed, this is particularly important for an industry that is dramatically expanding in some sea areas.
- MRED designers, developers and the consenting authorities need to consider the potential impacts on cetaceans for the entire life of the development from exploration, through construction and operation to maintenance and decommissioning, during all seasons of the year.
- Cumulative impacts from all developments in a region need to be considered when a site is being considered for development, taking into account the trans-boundary nature of cetaceans.